# which frequencies?



## dimmie (Jun 5, 2006)

hey all,

I recently bought myself a BK monolith to acompany my kef eggs. And the time has come for me to do some room eq. Because I have quite some boomyness going on, and I want to get a BFD in the near future.

So I guess first thing's first, I need to know where the spikes are in the bass department, so I guess I'm gonna need to create a map of my room. 

Can somebody tell me what frequencies to meassure?, is it smart to take every frequency ranging from say 20 hz. to 150 hz. which is the crossover I want to use. Because I've also heard somebody say to work with octaves.:blink: 

Thanks,

dimitri


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## Sonnie (Apr 11, 2006)

Hey dimmie and welcome to the Shack!

You might would consider using 80hz for your x-over.

As far as response measurements I would dive into to the Room EQ Wizard and take some sweep measurements from 20-200hz (which will actually measure 10-400hz) but then you can view what we all consider the normal 15-200hz and see what your response looks like.

Download and install REW... follow the HELP files step by step and then check out the REW Tips sticky thread in this forum here. That should give you a good start.


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## dimmie (Jun 5, 2006)

Sonnie said:


> Hey dimmie and welcome to the Shack!
> 
> You might would consider using 80hz for your x-over.
> 
> ...


thx sonnie,

should I change it just for measurements?, because I like my sound a whole lot better at this x-over.


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## brucek (Apr 11, 2006)

> should I change it just for measurements?, because I like my sound a whole lot better at this x-over.


No, measure with the crossover in plcae that you like. Measure with the sub only to equalize.

You also may find that once your sub is equalized, that a lower crossover may sound better. Any crossover higher than 80 can result in localization of the subwoofer itself, which many find objectionable....

brucek


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## dimmie (Jun 5, 2006)

brucek said:


> No, measure with the crossover in plcae that you like. Measure with the sub only to equalize.
> 
> You also may find that once your sub is equalized, that a lower crossover may sound better. Any crossover higher than 80 can result in localization of the subwoofer itself, which many find objectionable....
> 
> brucek


You're right, I know. with this crossover I have to keep the sub right next to my front three speakers. sound from my sub is VERY directional now, but as long as I keep it close it's pretty good.

I'll get around to the REW and start learning then, and post any questions that may come up.

thanks guys,

dimitri

p.s. has the BFD been discontinued?


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## brucek (Apr 11, 2006)

> p.s. has the BFD been discontinued?


It appears the 1124 was not available for a while, but that problem seems to have disappeared...



> sound from my sub is VERY directional now, but as long as I keep it close it's pretty good.


Yeah, you're losing stereo soundstage from your mains also.

brucek


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## dimmie (Jun 5, 2006)

Ok....

Am I right when I think I have to connect my pc to my spl meter?....because I figured I could just take my spl meter, take meassurements at different frequencies, write them on a piece of paper and enter those values into a computerprogram which would give me a graph, telling me which frequencies I have to alter using my bfd?.

Or do I have to move my pc downstairs and have it actually take those meassurements physicly?.

I am setting up my home theatre, not a pc soundsystem.

:dontknow:


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## brucek (Apr 11, 2006)

> Am I right when I think I have to connect my pc to my spl meter?


Depends on the accuracy you want.

The use of tones and SPL meter combined with an excel chart are available for download here here. Download the excel chart that matches the type of meter you will use and then download some tones and you're ready to go..

The more advanced method that most everyone here uses now is with a PC and a program called Room EQ Wizard (REW) and is also available on the downloads page...

Take your pick.

brucek


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## Otto (May 18, 2006)

brucek said:


> Take your pick.
> brucek


Hi dimmie,

brucek is right when he says "take your pick." However, if I were in your shoes, I'd be happy to carry a PC and monitor (a CRT, even!) to the site. It's worth it.



dimmie said:


> I am setting up my home theatre, not a pc soundsystem.


Correct. This is much more important than setting up a pc soundsystem... :yes: 

Go for it!


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## dimmie (Jun 5, 2006)

Can somebody tell me what kind of cable I'll be needing for the spl to pc connection?. If I leave my pc where it is right now, I'll need about 10 meters of it. Is that gonna be expensive?.

I'll also have to check if I've got the right input on my mainboard as I don't have a seperate soundcard, but onboard audio on the mainboard. I've got a standard line in jack, will that be sufficient?.

How do I run the sweep?, do I burn it on cd?, and play it on my dvd player?. Or do I have to send a signal from my pc to my amp with yet another cable?.

questions...questions

Help would be appreciated:T 

dimitri


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## brucek (Apr 11, 2006)

> If I leave my pc where it is right now, I'll need about 10 meters of it. Is that gonna be expensive?.


That's really too long. You will pick up too much noise. Drag your PC over to the system and get a sensible length set of cables....

Here's a wiring diagram:












> I've got a standard line in jack, will that be sufficient?.


Yep.



> How do I run the sweep?


Read all of this. Your questions will all be answered..

brucek


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## dimmie (Jun 5, 2006)

thanks again,

:T

What are the benefits over the connections that you exampled, and the one which doesn't include the amp in the chain(as seen on the supplied help files).

I would like to keep it as simple as possible as I'm starting to break out in sweat after doing some reading. I understand that in the second schematic one also meassures main speaker response. but as I want to equalize the sub foremost, won't that be enough for the moment?.

I'm just trying to keep the start as simple as possible, because it all sounds pretty pro to me.

dimitri

tell me if I'm wrong of course


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## brucek (Apr 11, 2006)

> What are the benefits over the connections that you exampled, and the one which doesn't include the amp in the chain


None. Actually you're at a bit of a disadvantage in that configuration because you don't have the bass management employed - which you want so you're able to track a standard crossover target in REW. 

Then after you equalize with the sub only, you add the mains and check for phase problems and any negative interaction around the crossover frequency. You can't do this if you feed the BFD directly.



> because it all sounds pretty pro to me


No, it's easy.

brucek


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## Sonnie (Apr 11, 2006)

Hey dimitri... it just looks intimidating because it's a lot of info. I thought the same thing and procrastinated using it for a while. I even think brucek procrastinated a little too in the beginning... not even close to being intimidating to him though. lol

We were somewhat encouraged by Bob (Malice) and brucek jumped in feet first and started to report back how easy it really was and actually I think he was having a lot of fun with it. I looked and thought... uh huh... that program is for the smart ones only.

I finally sat down and just took it one page at a time... HELP FILE! It really lays it out nicely when you do one step at a time. Once you've done it all once you'll look back and realize how easy it really is. It's really and truly not as bad as many people think.

Remember that we are here to help you if you run into a stumbling block.

I run from my soundcard output into my front inputs on my receiver so that I get the 80hz crossover included on my measurements. Not a necessity but an option and then you know how your x-over is effecting the response too.


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## dimmie (Jun 5, 2006)

I'll have to get some cables then....

:T


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## JimP (May 18, 2006)

I would be very careful about the assumption that you want a flat response across your sub frequency range into the crossover and above. Yes, you do want to eliminate wild peaks and dips, but beyond that, adding some SPL to the full sub range and a bump at 35 dbs can do more to improve your total sound than adding more woofage.


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## dimmie (Jun 5, 2006)

So, make the connection as stated in the example and let the amp(x-over) run along?.

I can measure first without the BFD right?, just to get a room response picture before I purchase the BFD?. It'll be some weeks before I can buy one.


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## brucek (Apr 11, 2006)

> I can measure first without the BFD right?,


Yep..


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## dimmie (Jun 5, 2006)

:T :T :T


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## dimmie (Jun 5, 2006)

hey guys,

I'm about to start measuring, but I was wondering if the line in/out plug which I use to connect my sub cable to my pc both have to be the double one showed in the schematic or that I can use two single ones?. I have to go shop for them this week, hope I can get them easy.

thank you


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## brucek (Apr 11, 2006)

> but I was wondering if the line in/out plug which I use to connect my sub cable to my pc both have to be the double one showed in the schematic


Yes, they do have to be stereo like the diagram......


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## dimmie (Jun 5, 2006)

why?, if I'm not using the second one?.

thanks

dimitri


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## brucek (Apr 11, 2006)

> why?, if I'm not using the second one?.


Because the soundcard uses stereo jacks. You can't put a mono plug into a stereo jack and expect the connection to be correct...


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## dimmie (Jun 5, 2006)

ok

:sn:


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## dimmie (Jun 5, 2006)

Another silly question.

I'm about to get some cables, but I'm wondering. Are those subwoofer cables?(in the diagram) and would 5 meters each be good?.

Thanks guys,

dimitri


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## brucek (Apr 11, 2006)

> I'm about to get some cables, but I'm wondering. Are those subwoofer cables?(in the diagram) and would 5 meters each be good?.


Those are standard coaxial interconnect cables with RCA type connectors shown in the diagram.
There is no such thing as a subwoofer cable - that's a marketing term.
No problem with five meters - you've got to reach between your computer and your receiver.

brucek


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## dimmie (Jun 5, 2006)

So, what people call a sub-cable isn't suitable?. Is there a difference between a "sub" cabel and a coaxial one?.

It's because I'm working with english terms here that make it confusing for me. I use coaxial cable myself for both my tv signal to my plasma, and my digital connection between dvd player and amp.


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## brucek (Apr 11, 2006)

> So, what people call a sub-cable isn't suitable?


Yes, a cable labelled sub-cable is fine. 



> Is there a difference between a "sub" cabel and a coaxial one


It's not that there is a difference between a coaxial cable and a sub-cable. A sub-cable is a coaxial cabel labelled for a sub. The labelling as such is meaningless.

brucek


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## dimmie (Jun 5, 2006)

Ok, thanks again bruce.

:T


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## Guest (Aug 22, 2006)

For decently cheap "computer to sub" wires look for the longest car stereo rca's as you need with female rca couplers in the middle if you need multiple wires to reach. You'll be running two wires anyway so they're both right there in the car stereo rca set.


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## dimmie (Jun 5, 2006)

Here it is...

look ok?


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## eddthompson (Aug 19, 2006)

Just a note on the cross over, i thought that the kef eggs being pretty small would struggle with the crossover at 80hz, but according to http://www.kef.com/KHT/KHT2005.2/sat_specs.htm they go down to 80hz, so it may be worth trying around there.

edd


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## brucek (Apr 11, 2006)

> Here it is...
> 
> look ok?


Yep...

brucek


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## dimmie (Jun 5, 2006)

eddthompson said:


> Just a note on the cross over, i thought that the kef eggs being pretty small would struggle with the crossover at 80hz, but according to http://www.kef.com/KHT/KHT2005.2/sat_specs.htm they go down to 80hz, so it may be worth trying around there.
> 
> edd



I already experimented somewhat with 80 hz. but I liked 150 hz!! a lot better. a low x-over takes a lot of clarity away from the keffs. It's set to 100 now. the only three options on my amp by the way. we'll see what the bfd is gonna do for me.


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## dimmie (Jun 5, 2006)

brucek said:


> Yep...
> 
> brucek


We'll get there someday, youll see:T


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## eddthompson (Aug 19, 2006)

dimmie said:


> I already experimented somewhat with 80 hz. but I liked 150 hz!! a lot better. a low x-over takes a lot of clarity away from the keffs. It's set to 100 now. the only three options on my amp by the way. we'll see what the bfd is gonna do for me.


Well, they are still small cones, by producing a lot of base the mid range could be affected quite badly.

only 3 options, pretty inflexible, hopefully, the sub can be cleaned up all the way to 150hz, and integrated better with the mains, but it will still be pretty directional, which isnt to much of a problem with it right at the front.

edd


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## dimmie (Jun 5, 2006)

I hope so....


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## dimmie (Jun 5, 2006)

Another question guys....

Does anybody have any tips what the best way is to install the mic.(splmeter)?. My thought would be to use an iron rod, screw it in the wooden part of the window and attach the meter to that(directly behind me), . another option would be to hang it from the ceiling from a string, but the attached cable would mess up the mic. being in the same place all the time.

I just figure I can't use a tripod, because I'd have to move the couch away and change the room response?.....

dimitri


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## dimmie (Jun 5, 2006)

Hereá a pic. of the area.


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## brucek (Apr 11, 2006)

> I just figure I can't use a tripod


Put it on the couch seat on a tripod in the position where you sit and point it toward the ceilng.


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## dimmie (Jun 5, 2006)

Which input on the amp should I use?, Because I can't find an "aux in", only cd in, phono in, md/tape in.

Will one of these do?.

I got the pioneer vsx-908 rds reciever.


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## brucek (Apr 11, 2006)

> Will one of these do?.


Yep, CD in will do fine...............

brucek


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## dimmie (Jun 5, 2006)

Ok bruce

have yourself a nice weekend.

Maybe I'll get around to do some meassuring this weekend, if not, next weekend, as I got a 2 week vacation a week from now.

dimitri


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## dimmie (Jun 5, 2006)

What's the difference between the beh. dsp 1124 and the 2496?

And which one has the preference?.


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## brucek (Apr 11, 2006)

The 1124 is preferred. It has 10 presets and the 2496 has one.............


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## dimmie (Jun 5, 2006)

Ok bruce, it just seems the 1124 is pretty hard to come by in holland....


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## brucek (Apr 11, 2006)

If you don't mind a single set of filters, then go for the 2496.......

I use two presets myself. One for music without a house curve, and one for movies.

I get lazy and usually leave the single movie preset on all the time unless I really want to do some critical listening to a new CD on my overly expensive CD player. 

Once I've listened and the CD gets moved from the CD player to my Sony jukebox (which I love), then I go back to the movie preset.

If I had to live with one preset, it would be fine.

I'd be interested how many peple actually use more than one preset on a regular basis???

brucek


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## Guest (Aug 31, 2006)

doh.. and i jsut ordered a 2496 too. 2496 looked newer and was slightly more expensive... although Its doubtful If I would use more than one preset anyways.


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## eddthompson (Aug 19, 2006)

brucek said:


> I'd be interested how many peple actually use more than one preset on a regular basis???
> 
> brucek


I was going to apply a few different curves, then set new curves based on output volume, ie, one curve for 60db, 65, 70, 75, 80, 85,90.

More just to see how room responce changes with volume :R 

edd


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## dimmie (Jun 5, 2006)

Well, I guess I'll go for the better and cheaper option. and trie to find a 1124. gives me more options for less money. While doing exactly the same thing, right?.


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## brucek (Apr 11, 2006)

> More just to see how room responce changes with volume


If you want to see this, then have a *single* set of filters and use REW to do a response at the different volume levels....

brucek


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## eddthompson (Aug 19, 2006)

i havnt had the time run sweeps or to set the filters yet, ive got a new subwoofer on order so im being lazy.

my theory is at 75 db you need to kill a peak by 3db, at 90db, the peak is even larger, so it needs more cut :R could be wrong though.

I got my bfd 1124 used for £50, no idea what that is in euros, about $90, total bargin for how much it improves the sound.


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## brucek (Apr 11, 2006)

> my theory is at 75 db you need to kill a peak by 3db, at 90db, the peak is even larger, so it needs more cut


In reality likely not, but in perception it may indeed be so. The frequency response of hearing at low sound pressure levels drops off rapidly for both low and high frequencies. This weakness was the idea behind the "loudness" button you might see on some older receivers. Compensation today for such a response curve with respect to sound level could easily be ameliorated within a DSP, but I don't suspect that's being done too often.

brucek


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## dimmie (Jun 5, 2006)

I'm gonna take first meassurements tonight, when setting the input volume and the measurement level, should I use the speakers or the sub to meassure?, as asked in the little dialogue box?...

dimitri


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## brucek (Apr 11, 2006)

> should I use the speakers or the sub to meassure?,


SUB


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## dimmie (Jun 5, 2006)

Well.....

I think I have the measurement level, input volume, spl calibrated and so far no problems.

I'm now tackling the soundcard calibration measurement, and the first part was ok, a pretty straight line with a roll off at the beginning and end. with a rimple at the end. 

When I checked the calibration, I got the message that the highest level in the measurement is -21,7?.

And apparently that's too low....What is the smartest thing to do now?, I don't want to turn up the amp any further, as it is already at 0.


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## brucek (Apr 11, 2006)

> When I checked the calibration.............


Are you referring to the checking of the soundcard calibration, in that it was successful before doing any more measurements?

If so, did you select a TAB *other than the soundcard tab to do this* as is specified in the Help files?

brucek


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## dimmie (Jun 5, 2006)

Yes I did, when I made the soundcard calibration measurement all looked ok. After that the help file tells you to select the left channel and check if the calibration was succesfull. I then get the message that the highest level in the measurement was too low(-21.7).


I hope I'm being clear enough, in my questioning.


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## dimmie (Jun 5, 2006)

The red line in the "left"graph is around the 67 db. point. Which means it's too low right?, My real question is: Shouldn't this red line be around 75 db.?. And What's the best way to get it there?. Which volume should be changed?.

thanks


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## dimmie (Jun 5, 2006)

I've upped the soundcard volume a bit, and now the red line reads about 75 db. But the previous measurements have been made with the soundcard volume in the middle. Should I leave the soundcard volume as it is now?, and start from the beginning, or can I just continue to room response measurements?. I'm afraid that my measurements will be off now. Because I've changed the soundcard output volume.

EDIT; I've upped the measurement level to -12 db. which gives me a straight red line at 75 db. The soundcard output is back in the middle now. Iguess I'm ready to start measuring. just have to set the target level, right?.


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## dimmie (Jun 5, 2006)

Here's the first one, I can't realy make heads or tales from it......

Hope it will make some sense to you.


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## dimmie (Jun 5, 2006)

And after restarting the program, and measuring again, I got this.

:coocoo:


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## brucek (Apr 11, 2006)

Set the vertical scale from *45db to 105dB* and the horizontal scale from *20hz to 200hz*.

Measure the sub only with the crossover set to your normal crossover and the mains shut off...

brucek


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## dimmie (Jun 5, 2006)

brucek said:


> Set the vertical scale from *45db to 105dB* and the horizontal scale from *20hz to 200hz*.
> 
> Measure the sub only with the crossover set to your normal crossover and the mains shut off...
> 
> brucek


Can I shut the mains off in REW?, or do I have to disconnect them?


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## brucek (Apr 11, 2006)

> Can I shut the mains off in REW?, or do I have to disconnect them?


REW is simply a signal generator that feeds your receiver, just like a CD player. It has no control over your systems speakers.

If you have a seperate amplifier for your mains, shut it off. If not, remove your speaker cables (with the power off) to the mains and don't allow then to short together. Obviously you'll have your receiver in stereo mode, so that no other multi-channel speakers will be on besides the mains.

brucek


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## dimmie (Jun 5, 2006)

Here's the next one, looks a lot better.

One question though: When I close REW and start it up again later, do I have to make new calibrations before I begin?. or does the program remember these?.

I didn't calibrate anything today, before I ran the sweep.

Is the dotted line the soundcard response?.

thanks,

dimitri


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## brucek (Apr 11, 2006)

> When I close REW and start it up again later, do I have to make new calibrations before I begin?


Yes, since all the variables that control the setup have changed.... i.e. receiver levels, soundcard levels, microphone positioning etc.

REW will of course remember your soundcard calibration because it will load the file you created for it. You don't ever have to do that again.

Once you've done it a few times, the REW setup takes seconds...



> Is the dotted line the soundcard response?.


Yes, you can turn that off the display with the same buttons you used to turn off the display of the RS meter calibration file graph.

brucek


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## dimmie (Jun 5, 2006)

Ok, I'll start from the top again and see what changes.

I'll even make a new soundcard calibration file because I had some trouble yesterday with the output volume and played with the volume controls. It turned out I had to select the soundcard itself and not the java engine. because java didn't give me the proper volume(I think). 

Or would you say that's not nescessary and the soundcard is properly calibrated?. Maybe you can tell just by looking at the graph.


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## brucek (Apr 11, 2006)

Looks fine in the frequency area you're using it.........


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## dimmie (Jun 5, 2006)

Ok, I'll leave that as is.

I calibrated and came up with this one.

What's your verdict bruce?, pretty big dip at 29 hz?.......will this be a problem, or is this a treatable response graph?. It doesn't show how low the monolith goes, does it?.

I guess I'll start reading my BFD manual, I'll have to get some rca/phono to jack plugs tomorrow. 

Is there anything else I need to do before I start filtering?.

Dimitri


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## brucek (Apr 11, 2006)

> What's your verdict bruce?, pretty big dip at 29 hz?.......will this be a problem, or is this a treatable response graph?. It doesn't show how low the monolith goes, does it?


The response is pretty good. The peak at 46Hz is the one that would cause a bloated sound. The BFD will take care of all the peaks without any problem. The dip at 29Hz is too narrow to notice. It does tend to drop off at 30Hz though. Do you have it in a corner - that would be best to bring that bottom end up. That monolith shouldn't be down that far at 20Hz (~-10dB)...

brucek


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## dimmie (Jun 5, 2006)

brucek said:


> The response is pretty good. The peak at 46Hz is the one that would cause a bloated sound. The BFD will take care of all the peaks without any problem. The dip at 29Hz is too narrow to notice. It does tend to drop off at 30Hz though. Do you have it in a corner - that would be best to bring that bottom end up. That monolith shouldn't be down that far at 20Hz (~-10dB)...
> 
> brucek


I have it in a corner, and I'm sitting in the opposing corner. 

I'll add a photo.


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## brucek (Apr 11, 2006)

Looks like a large room with vaulted ceilings...

Your satellite mains are quite small, what do you have the sub crossed at - 80Hz?

brucek


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## dimmie (Jun 5, 2006)

It's approx. 5 meters wide, 7 meters long and that's not counting the kitchen which takes a piece out of that space(as you can see in the second picture). I'm basicly in an L shaped room. The ceiling is about 2.5/3.0 meters high.

I've got the x-over set at 100 hz. now which is the middle option on my amp(80/100/150)

Should I measure all three?, I liked my sound the best at 150hz. really. But I did lose a lot of my stereo soundstage that way.

Dimitri


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## brucek (Apr 11, 2006)

> I've got the x-over set at 100 hz


Yeah, that's probably best, but the reason I asked is because to me it looks like the crossover is at 80Hz in your graph, both the subs response and REW setting?

Here's a 100Hz crossover set on REW - it looks different than yours......












> I liked my sound the best at 150hz. really. But I did lose a lot of my stereo soundstage that way.


Yeah, no doubt, given the size of the mains. But, as you say, you will lose a lot of separation. You'll have to decide...

brucek


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## dimmie (Jun 5, 2006)

Maybe I've made another mistake, because the "cut off" in the filter panel is at 80, this is the selected x-over right?....So it should be set at 100 for these readings?.......

dimitri


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## brucek (Apr 11, 2006)

> the "cut off" in the filter panel is at 80, this is the selected x-over right?....So it should be set at 100 for these readings?.......


Yes, it should be set at 100Hz in REW if the selected crossover in your receiver is set at 100Hz. This then displays and uses a 100Hz target for REW to adjust its filters.

Ensure your receiver is at 100Hz also...

brucek


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## dimmie (Jun 5, 2006)

ok thanks again bruce.

I'll make 3 new measurements tomorrow, with the right setting in rew, at the three x-overs.

See what that does, I'm a bit worried about the -30 hz levels though....

We'll see tomorrow.

dimitri


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## dimmie (Jun 5, 2006)

Well here they are.....

The measurement level had to be changed a bit, The amp is at +3 now.(instead of 0) so they look a bit different. Tell me what you think bruce!.


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## brucek (Apr 11, 2006)

Well, they're all showing the same peaks and valleys - just extended crossover points. That's fine, but the reason to test multiple crossovers (before filtering) would presumably be to make a decision based on the capabilities of your mains.

To make this crossover decision, you need to connect the mains and do the exact same measurements over to see how the mains integrate at the different crossovers.

Once you've done that and decided on a crossover to use, then disconnect the mains and get on with the filtering process.....

brucek


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## dimmie (Jun 5, 2006)

Ok, thanks bruce, I'll connect them and make the new measurements.

dimitri

p.s. When setting the input volume on the bfd, I only get 2 green led's. It won't go into the yellows and reds. Even when I turn up the lfe channel volume on the amp, is it possible that my amp doesn't produce enough bass. Would seem strange to me because it's a 110 watt amp....


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## dimmie (Jun 5, 2006)

Ok, with the mains included....


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## brucek (Apr 11, 2006)

> When setting the input volume on the bfd, I only get 2 green led's


What signal are you sending the BFD to produce the 2 green LED's ?

Are you adjusting the subwoofer output trim level of your receiver to increase/decrease the level to the BFD ?

The standard procedure is to play a DVD like U571 and push the BFD IN/OUT switch to show "input level" in the LED's and then turn the receiver volume as loud as you would likely have it, and then adjust the receiver subwoofer output trim to see the Yellow LEDS come on in explosions etc...



> is it possible that my amp doesn't produce enough bass. Would seem strange to me because it's a 110 watt amp....


Realize that the signal going to the BFD and then the subwoofer is a line level signal and has nothing to do with the power associated with the power amplifiers that feed the rest of the speakers in your system. The power associated with a subwoofer is derived from its own internal amplifier, not your receiver. The level from your receiver is controlled by the volume conntrol and the trim level.

brucek


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## brucek (Apr 11, 2006)

> Ok, with the mains included....


I would suggest using the 150Hz crossover. The mains appear to not be capable of extending low enough to support the 100hz cross.....

brucek


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## dimmie (Jun 5, 2006)

brucek said:


> What signal are you sending the BFD to produce the 2 green LED's ?
> 
> Are you adjusting the subwoofer output trim level of your receiver to increase/decrease the level to the BFD ?
> 
> ...


I have the lfe output set at minimum on the amp channel(-10) and I've got the sub gain set at about 10%, because I get excessive bass output really fast, due to the power of the monolith and the nature of my rooms response(I guess). If I want to even out the sub and mains I have to trim down the sub channel. This is probably the reasion the BFD is getting a weak signal. I also have a bass peak level manager on the amp, which controls the maximum amount of bass released by the amp. Which is set pretty rigidly also. 

I just played a movie to check the led's reaction, attack of the clones, with some explosions. turned up the amp pretty high, with a maximum of 2 green led's.

I tried turning the lfe channel adjuster up to 0(and even higher), with no real improvement on the BFD. 

Will a crossover of 150 hz. on the amp give me more power on the BFD?(stronger signal)?, because I tested on 100 hz. x.

Dimitri


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## brucek (Apr 11, 2006)

> I have the lfe output set at minimum on the amp channel(-10) and I've got the sub gain set at about 10%, because I get excessive bass output really fast,


Ignore the level of the subwoofer amplifier itself until you get the level of the receivers output to the BFD set. Simply turn up the LFE output and turn down the subwoofer amp. You need the input level to the BFD set first. Then bring up the level of the sub amp itself to suit..



> Will a crossover of 150 hz. on the amp give me more power on the BFD?(stronger signal)?


 The input to the BFD does not translate to power levels. It understands voltage levels. A higher crossover will provide more signal at the frequencies up to 150Hz, but not more level. If you need more level turn up the subwoofer output level on the receiver.

brucek


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## dimmie (Jun 5, 2006)

brucek said:


> Ignore the level of the subwoofer amplifier itself until you get the level of the receivers output to the BFD set. Simply turn up the LFE output and turn down the subwoofer amp. You need the input level to the BFD set first. Then bring up the level of the sub amp itself to suit..





> Will a crossover of 150 hz. on the amp give me more power on the BFD?(stronger signal)?





> The input to the BFD does not translate to power levels. It understands voltage levels. A higher crossover will provide more signal at the frequencies up to 150Hz, but not more level. If you need more level turn up the subwoofer output level on the receiver.)?
> 
> brucek



I'm away tomorrow and I'll be back sundaynight. maybe I'll report back to you on sunday.

have a nice weekend

:T


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## dimmie (Jun 5, 2006)

Was I supposed to use the correctional values for the radioshack meter?, I was under the impression that you only needed these for manual(non-REW) measurements. But they just came to mind.

I also realised that the amp I'm using(pioneer vsx-908/110 watts) has a bass peak manager utility. Which controls the maximum amount of bass that the amp delivers. So I connected the bfd in the chain and as I turned up the max. bass peak level on the amp, the green leds turned yellow and eventually red. Should I just turn it up all the way on the amp?. And let the BFD handle all the bass management?. Or should I allow it just to hit the red led?, and let the amp cut everything above that?.

:T


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## brucek (Apr 11, 2006)

> Was I supposed to use the correctional values for the radioshack meter?,


Yes.



> I also realised that the amp I'm using(pioneer vsx-908/110 watts) has a bass peak manager utility. Which controls the maximum amount of bass that the amp delivers.


Shut it off or set it at maximum level, and then set up the input level to the BFD as described in the BFD guide.

brucek


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## dimmie (Jun 5, 2006)

I guess it's back to the drawing board. But it's ok. I'll put the bass peak at max. on the amp.

A friend of mine on the av forums told me I probably have a phase issue at the crossover piont, because I have a dip preceding and after the crossover. What's your opinion on that?, You can find the graphs a few posts back.

If there is a phase problem, Should it be handled now or after the sub is EQ'd?


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## brucek (Apr 11, 2006)

> You can find the graphs a few posts back


Are the graphs really valid since you didn't use a calibration file for the meter?



> If there is a phase problem, Should it be handled now or after the sub is EQ'd?


As much as possible before, then eq the rest.

brucek


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## dimmie (Jun 5, 2006)

brucek said:


> Are the graphs really valid since you didn't use a calibration file for the meter?
> 
> 
> 
> ...


I'll take new measurements tomorrow with a calibrated spl meter. at the three x-overs. with the mains included. for a possible phase problem. 

I already experimented by changing the sub distance in the receiver menu. at various setting. I'll do that again tomorrow. My initial setting turned out to be the best tonight, I'll see what happens tomorrow.

Dimitri

p.s. do you have to set a target level even when you've gone through the calibration procedure at startup?


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## brucek (Apr 11, 2006)

> do you have to set a target level even when you've gone through the calibration procedure at startup?


You need a target level to calculate filters


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## dimmie (Jun 5, 2006)

I'll be measuring my sub alone first, and then team it up with my mains. and measure three x-overs. Should I recalibrate when I start using the mains also?. Or is the sub calibration sufficient for all measurements?, sub alone and sub+ mains?.

dimitri


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## brucek (Apr 11, 2006)

> Should I recalibrate when I start using the mains also?.


No, one calibration per session............


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## dimmie (Jun 5, 2006)

Ok, here they are.

Sub alone/sub+mains 80 x/sub+mains 100 x/sub + mains 150 x.

What should I do next?, start creating filters for the sub?.


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## brucek (Apr 11, 2006)

Well, it doesn't look like there is much difference between the three responses when I line them up?

Hopefully you actually changed the crossover in your receiver. If so, then I guess using 80Hz would be best.










Just read the sections in the help file on creating filters and also read this post and carry on.

brucek


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## dimmie (Jun 5, 2006)

> Hopefully you actually changed the crossover in your receiver


I know what you mean bruce, they look pretty much alike. But I did change it...

I actually programmed one filter just for the **** of it, and it worked pretty good. I'll post it tonight and I;ll get on to the other ones too.

dimitri


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## dimmie (Jun 5, 2006)

I made some emasurements tonight, and noticed something strange.....

These have been taken right after eachother with the same settings.

Do you have an idea of what's happening bruce?


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## brucek (Apr 11, 2006)

> Do you have an idea of what's happening bruce?


No. Just ignore the anomoly and re-measure and then set your filters.


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## dimmie (Jun 5, 2006)

Ok, I detected the peaks and applied two auto filters and one manual, because of a small peak that remained. But after this I guess it's time to start adressing the dips.... 

What should the next step be?.


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## brucek (Apr 11, 2006)

> What should the next step be?.


Well, that's up for debate. 

I see you've used a target of 150Hz. Why did you choose that and not 100Hz?

Either way, You've done a good job, although I might add a filter to reduce the peak at ~80Hz somewhat.

As far as the dips are concerned, I'm not a big fan of using gain when using a parametric amplifier, since it reduces headroom in the unit itself. A small amount can be tested on dips to see if it's effective. Don't ever go over +5dB....

brucek


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## dimmie (Jun 5, 2006)

Headroom won't be a problem(for the sub), is there nothing I can do to get my response better than it is now?, I figured this was just the starting point....

Are all the remaining low points in my graph basicly non-treatable?

I'll trie 100 hz. if you thinkÏ'll get better results that way, or even 80. My goal was to treat the subs response as far as I could. All the way up to 150 hz.


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## brucek (Apr 11, 2006)

> Headroom won't be a problem


Really, how have you determined that?



> My goal was to treat the subs response as far as I could. All the way up to 150 hz


That's not the way it's really done. You choose a crossover first, taking into consideration the low end response of your mains. If they're capable you choose 80Hz. If they're not, you can go as high as 100Hz. After that the sub is far to localizable.

Set your crossover and create the filters to get the best response for that target. Add the mains and tweak anything around the crossover - that's it.

If you have a bunch of dips, them's the breaks - not much you can do except add a little gain - and I mean a little. Every dB of gain comes off your headroom or reduces dynamic range....

brucek


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## dimmie (Jun 5, 2006)

I was under the impression that headroom referred to the sub....I was pretty confident that I had enough on the sub to play with. But you're referring to the bfd?, Ok I didn't know.

Have you ever seen a graph as bad as mine?, weak below 30 hz., weak between 50 and 80 hz. those are important freqencies I believe...

I'll trie to go for 100 hz. x-over..see what happens.


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## dimmie (Jun 5, 2006)

I'll trie it at 100 hz. x-over. see if I can get better results that way.

I put the mic. in the middle of the room, and came up with this. probably a better location to sit, right?.

Maybe I should measure the keffs first, to see how low they'll realy go. and then choose my crossover


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## brucek (Apr 11, 2006)

> I put the mic. in the middle of the room, and came up with this. probably a better location to sit, right?.


Well, it's usually the worst you can choose.....

100Hz cross looks like it's good - I would leave it there.

Do you have problems with the way your systems sounds now after applying the filtering?

brucek


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## dimmie (Jun 5, 2006)

Just another thought.....

I started to raise to gain on the sub, and further decrease the gain on my three filters(for the peaks). I fgured that the more I reduced the gain on my peaks, the closer they would get to where my dips are. And it seems to work.

Here my latest graph.

Is there any fault to my way of working now?, because the graph looks a h*ll of a lot better now....

I do have one question though: The behringer doesn't seem to apply double filters on the same frequency, because when I upped the sub's gain I developed new "peaks" and by adjusting my excisting filters I put them down to my target level again. bringing them closer to the low points in the graph.


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## dimmie (Jun 5, 2006)

brucek said:


> Well, it's usually the worst you can choose.....
> 
> 100Hz cross looks like it's good - I would leave it there.
> 
> ...


I feel that the bass is not what it should be, I feel I'm realy missing some stuff in the bass department. The boom has reduced!, that's a fact, and I can turn my system all the way up now with proper bass at high volumes, which has been a problem lately(because of the amp's bass management). which I turned off now. So I feel I've gained quite a lot already, and if you look at the above, maybe even more!......

Thanks brucek,

dimitri


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## brucek (Apr 11, 2006)

> Is there any fault to my way of working now?, because the graph looks a h*ll of a lot better now....


It's fine as long as you don't go too far with it. 

You're simply changing the level in relation to the target. Think of it this way. If you did a measurement and all the signal was below the REW target, then no filters would be suggested. If you increased the gain of the subwoofer amp and the signal was somewhat above the target, then REW would suggest filters for all the peaks. While these filters would solve the peak problem, you've lost headroom in your subwoofer amplifier by turning it up. If the amp has lots of headroom your fine. 

Maybe work on that peak at 80Hz a bit...... and perhaps the one at 38Hz.....

brucek


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## dimmie (Jun 5, 2006)

brucek said:


> It's fine as long as you don't go too far with it.
> 
> You're simply changing the level in relation to the target. Think of it this way. If you did a measurement and all the signal was below the REW target, then no filters would be suggested. If you increased the gain of the subwoofer amp and the signal was somewhat above the target, then REW would suggest filters for all the peaks. While these filters would solve the peak problem, you've lost headroom in your subwoofer amplifier by turning it up. If the amp has lots of headroom your fine.
> 
> ...


That was the next thing I wanted to ask you.....I already tried to fix the peak at 80 hz. but no amount of cut will decrease it....

Can peaks be as stubborn as dips?, 

I've got loads of headroom on the sub, it's pretty powerfull. I believe I'm not even using 25% on it right now, with the lfe channel on the amp set to -5. I believe I've increased the cut on my excisting filters about - 7 db.

I've been testing with "the incredibles" and the bass seems a lot more tight and in place. Whenever I take a reading on the spl meter, it's a lot more stabile, in the unequalized situation it's all over the place when I take a reading. 

Any tips on the 80 and 38 hz. ?

Dimitri


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## brucek (Apr 11, 2006)

> Can peaks be as stubborn as dips?,


Nope. You must not have had 80Hz selected or the filter was not in PA mode. Be sure you had 80 and not .80 selected.



> I've got loads of headroom on the sub,


Yep.



> Any tips on the 80 and 38 hz


hehe, enter filters at those frequencies and cut......remeasure and see how you did....that's it.

brucek


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## dimmie (Jun 5, 2006)

Will do.....

:T


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## JohnM (Apr 11, 2006)

dimmie said:


> I already tried to fix the peak at 80 hz. but no amount of cut will decrease it....


That resonance is probably being driven by your main speakers so filtering the sub won't help, could confirm that by turning off the sub and re-measuring. Try inverting the sub phase to see if that makes the overall response better or worse.


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## dimmie (Jun 5, 2006)

Thank you for that one john, I'll give it a go tonight.

Dimitri


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## dimmie (Jun 5, 2006)

Here's the latest one....

I'm now using 8 filters, the bass is pretty ok now, but I feel that the integration with the satelites isn't what it should be. What's the best way to get fix this problem?.

thanks again

dimitri

p.s. I'm also just randomly inputting filters, should the lowest one be the first?.


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## brucek (Apr 11, 2006)

> I'm also just randomly inputting filters, should the lowest one be the first?.


Doesn't matter.



> What's the best way to get fix this problem?.


What problem? Looks like you've equalized the subwoofer - job done.



> I already tried to fix the peak at 80 hz. but no amount of cut will decrease it?


You didn't say how you eliminated your pesky 80Hz problem that you said wouldn't respond to a filter..

brucek


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## dimmie (Jun 5, 2006)

> You didn't say how you eliminated your pesky 80Hz problem that you said wouldn't respond to a filter..


Well...just like you said, I had the .80 selected, and not 80.:T 

But after having tested with different material, I've concluded that I don't really like my bass response now with the 8 filters. It looks good on paper but a house curve doesn't have to be a flat line right?...

It sounds really "engineered" now. and not dynamic at all.

I guess I'll test some more and see what happens. Any tips would be appreciated.

Dimitri

p.s. I've got 2 filters on now, with better "perceived" results.


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## Guest (Sep 17, 2006)

What you'll find is the response will vary depending where you sit the room. You've only eq'ed for one position so anywhere out of this zone will be all over the place. In some cases it can actually be worse than before in other seats. This is where having room treatments helps smooth things out so it's not as different in all the seats.


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## brucek (Apr 11, 2006)

> Well...just like you said, I had the .80 selected, and not 80.


Yeah, it's a really common mistake. I blame the BFD for its poor indicators. Since your crossover was 100Hz, it wasn't likely your mains causing the problem because they have much less effect at 80 Hz than the sub itself... Glad you found it.



> a house curve doesn't have to be a flat line right?...


A house curve isn't a flat line at all. It's a curve. In fact, I would suggest that your dislike of the sound has to do with the fact that your sub is at exactly the same level as your mains. Turn it up a few dB and see if it sounds better..

brucek


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## dimmie (Jun 5, 2006)

Does the amount of filters used have a possible negative effect on your sound?, which would you say is better: using a lot of filters and getting a smoother curve or less filters and getting an almost as smooth curve?. I just felt that, to achieve a 2-3 db. cut, with an extra filter, will cost you more than you will gain.... 

I've tried the two testtones: 32 and 100 hz. to see if the perceived volume comes close, but no, not even with the wide cut at 366hz. as described in the house curve thread.done just for the **** of it.

I came up with this one last night.

p.s. from a h 100 hz. up it looks pretty bad also, can I do anything about that?.


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## brucek (Apr 11, 2006)

> which would you say is better: using a lot of filters and getting a smoother curve or less filters and getting an almost as smooth curve?. I just felt that, to achieve a 2-3 db. cut, with an extra filter, will cost you more than you will gain....


Good question - it depends I guess. 

Each filter comes at the expense of a modified phase at its frequency that may cause more problems than the cut or gain solved. It all depends on your system. You be the final judge. I find most people on these forums frigg around too much with a dB here and there and it doesn't matter a **** because if they move a foot one way or the other it's all different.

The big bonus comes from reducing those large wide peaks caused by resonances. Once that's done the rest is just for fun....

Again I say... looking at your graph (which is really good), I would recommend turning up your subwoofer amp a few dB and see if it sounds better. Then you're done. Live with it for a while.



> p.s. from a h 100 hz. up it looks pretty bad also, can I do anything about that


Joint the club. Some people find certain room treatments solve specific problems, but I think most people have a graph above 100Hz that looks like yours.... It's the low frequency peaks that cause all the trouble......

brucek


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## dimmie (Jun 5, 2006)

I'm gonna screw around a little more, see what happens....

Thanks a million for your help brucek.:T 

They're not paying you enough.........probably nothing:thumbsdown: 

:T :T :T 

p.s. maybe look at the crossover point dip, see if it's a phase problem.


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## dimmie (Jun 5, 2006)

I just played with the sub distances in the amp menu.....

can it be that the measured distance isn't right at all?.....it seems to be.

Taking into consideration the extra ms that the behringer uses I measured 3.9 m. 3.6 for the sub + 0.3 for the behringer.

Here are the graphs.

I'm sorry but I don't know how to make them all visible underneath eachother.


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## brucek (Apr 11, 2006)

> can it be that the measured distance isn't right at all?


The mesaured distance is no doubt correct. Once set, we normally then adjust the subwoofer phase control to correct to the best resulting signal around the crossover region.

If you don't have a phase adjustment, you can substitute a time delay adjustment on the sub which will act as a reasonable approximation for a phase adjust.

You have demonstrated this in your graphs in that as the time changes the crossover region gets better.

brucek


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## dimmie (Jun 5, 2006)

brucek said:


> The mesaured distance is no doubt correct. Once set, we normally then adjust the subwoofer phase control to correct to the best resulting signal around the crossover region.
> 
> If you don't have a phase adjustment, you can substitute a time delay adjustment on the sub which will act as a reasonable approximation for a phase adjust.
> 
> ...



I do have a phase switch ofcourse, I'll take the measured distance and play with the phase. But I also realized that I entered a new filter at that point, which I totally forgot about yesterday. So I'll have to turn it off and see what I can do with phase alone.

The least dip at the x-over point is the best phase, right?.

thanks

dimitri


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## brucek (Apr 11, 2006)

> The least dip at the x-over point is the best phase, right?


Yep, and as you've noticed, after you set the best phase, if it's only a switch and not variable, then you might tweak the distance a little if its effective in removing more of the problem. Usually before you play with either phase or distance, it's best to move the sub around to different locations, but this is sometimes not possible because of WAF or layout..


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## dimmie (Jun 5, 2006)

It's a variable. As soon as I get a chance I'll work on it.

Moving the sub right now, is not an option. Taking into consideration that I have baby-twins and everything fragile in the house has to have some barrier in front of it:surrender: . It's pretty safe where it is, and it's not in the way. 

Dimitri


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## dimmie (Jun 5, 2006)

Hey bruce,

I've been adding some extra filters, I'm at 10 now. 

Is 12 filters the maximum amount?, because I'd like to trie and experiment with house curves. But I think my response is not smooth enough to do this(I think).

Bass response is pretty good now, but I'd just like to give it a go.

:T


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## brucek (Apr 11, 2006)

> Is 12 filters the maximum amount?


Yeah, 12 is the limit. Most people can get the response they want in that amount......


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## JohnM (Apr 11, 2006)

If you are keen you can loop the output of one channel to the input of the next and have 24 filters.


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## dimmie (Jun 5, 2006)

Yeah, I think I understand.

Just connect input 1 to input 2........e voila!.

I'm starting from scratch to see if I can apply filters more effectively now, and hope I won't need 2 channels.


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## dimmie (Jun 5, 2006)

five filters.


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## brucek (Apr 11, 2006)

> five filters


Yep, good job. Whenever I read someone ask about using more than 12 filters, my reaction is, "try harder"....

That's a really good response. Now to add a house curve, the easiest method for you would be to turn up your subwoofer amplifier a few dB and then use a few filters (including the ones you're using if necessary) to slowly drop the area from ~40Hz to ~90Hz if possible.

Something like the target shown below:


---------------------









---------------------

brucek


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## dimmie (Jun 5, 2006)

Ok, thanks for your time. and the graph.:T 

I'll get around to it tomorrow

for now.....:snoring:


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## dimmie (Jun 5, 2006)

8 filters, I guess this is as flat as I can get it with this number.

The waves in between 15 and 30 hz. aren't gonna be annoying, are they?. I wouldn't know any material at these frequencies to test it.

Now on to the house curve.


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## dimmie (Jun 5, 2006)

Brucek,

Regarding the input level on the BFD, mine is probably set too low. Because of my sub's power, the best way to set it up is by turning down on the av amp, and adding extra gain on the sub itself. Because if I set the av volume at say: 0 or +5 the sub will always be too loud, even at it's lowest gain.

And the bfd probably needs at least 0 on the av amp for it's input(probably higher) 

I'm asking this because I was reading your review on the BFD and you mentioned that the quietest signal might not be processed properly when the input level is set too low. 

The most led's I've seen are 2 maybe 3 green.

thanks

dimitri


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## brucek (Apr 11, 2006)

> 8 filters, I guess this is as flat as I can get it with this number


The response using 5 filters would have been quite sufficient. You don't need to get it ruler flat. It's just not neccessary.



> Because of my sub's power, the best way to set it up is by turning down on the av amp, and adding extra gain on the sub itself. Because if I set the av volume at say: 0 or +5 the sub will always be too loud, even at it's lowest gain.


I don't really understand why the subs volume doesn't dial down to zero? You should be able to completely control its level with the gain dial.



> The most led's I've seen are 2 maybe 3 green


Even when you play a bass heavy DVD at the loudest you would ever listen? Be sure to be monitoring the BFD's input LED's and not the output LED's.

brucek


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## dimmie (Jun 5, 2006)

> The response using 5 filters would have been quite sufficient. You don't need to get it ruler flat. It's just not neccessary.


ok, back to five.





> I don't really understand why the subs volume doesn't dial down to zero? You should be able to completely control its level with the gain dial.


I checked again yesterday, with the filters it's easier to control the sub.





> Even when you play a bass heavy DVD at the loudest you would ever listen? Be sure to be monitoring the BFD's input LED's and not the output LED's.


I'll recheck, weith the BFD in bypass

I made a start with the housecurve..


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## dimmie (Jun 5, 2006)

Which would you say is the best phase?.....

Is the area past 100 hz. important?

these are from 0 to about 75 degrees approx. in five steps


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## brucek (Apr 11, 2006)

I like door number three.

Why don't you filter that peak at 78Hz.............


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## dimmie (Jun 5, 2006)

I already did, but I bypassed that filter to get a clear crossover picture.

Thanks. 

I'll get on to the house curve.


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## dimmie (Jun 5, 2006)

Man, I can't get that crossover response back...I changed some things yesterday.

A big dip at about 150 nhz. which won't go.....


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## dimmie (Jun 5, 2006)

I'm upping the volume on the sub, for the housecurve.

And this is what happens.....the region from 100 hz. and up rises with the sub volume.....

Cross is at 100 hz.......

It seems it's still the sub after 100 hz.

any idea?


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## brucek (Apr 11, 2006)

> any idea?


lower the crossover to 80Hz and up the volume....... retest


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## dimmie (Jun 5, 2006)

Here's 80 and 100 hz. cross respectively.

I think you're right ken.......at 80 hz. x-over it seems the sub level is unaffected after 80 hz.

Is this normal for a 5.1 receiver?...

Thanks

Dimitri


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