# Looking for Input - First Run at REW



## YW84U (Apr 29, 2007)

Good Evening All,

Well, I managed to pick up an ECM8000 and a Xenyx802 at a Boxing Day sale, and thought it was the perfect time to start my calibration journey! 

A bit of background on my setup:

Dedicated HT:
12ft 6 in wide
19 feet long
90 in high

Speakers are Paradigm Monitor 7 mains, Paradigm CC270 Centre, Paradigm ADP-170 surrounds with a Paradigm PS-1000 Sub, located in the front left corner of the stage/proscenium (yes, bad, bad, bad...). The entire front stage (minus the screen) is filled with mineral wool for bass-trapping, plus I have 2" OC703 panels at all first reflection points on walls and ceiling. A Sony STR-DE945 AVR drives the speakers with the xo at 90hz, and a Sony STR-345 driving 4 Aura bass shakers in the sofas. Both the Sub and the Shakers are through a BFD.

My mission is to use REW / BFD and anything else I can get my hands on to tweak and improve the audio! Looking at Wayne's hard-knee house curve and/or variants as well. I am planning on taking measurements for all 6 seating locations, and setting up the filters on the BFD according to which seats are occupied (Setting 2 = seats 1&2 occupied, setting 4 is four people, etc.). I will be using the left engine to PEQ the sub, and the right will be used as a 40hz low-pass for the shakers on all of the settings....

I've setup REW, calibrated the Soundblaster Live External SC, used the ECM8000 cal file from the site, set levels and taken some baseline measurements (no BFD) of all six positions in the room :yay:

Here's a pic of the room layout, so the seating 'numbers' make sense:











And what follows are my very firstest measurements :help:

Seat 1









Seat 2









Seat 3









Seat 4









Seat 5









Seat 6











It appears to me that 4 and 5 are not too terrible to start with, but seat 3 is the worst of the bunch  Methinks that once I start to apply the filters, Seat 3 is going to lose no matter what! What I've observed is, that guests generally fill seats 3 & 6 last - usually the first seat they head to is #5 and they're scared to sit in #1 :scratchhead:

Now, to begin designing filters to address multiple locations, am I better off to use the 'average' function in REW for different combinations (ie - if seats 4&5, 1& 2 are used, then 'average' those readings and filter for the average)?

I'll also have a ton of questions in regards to integrating the mains (once I get a feel for setting up the sub), and am also looking at taking full range measurements down the road.

Any suggestions or advice that could help me towards auditory nirvana is greatly appreciated!

Thanks in Advance,


----------



## atledreier (Mar 2, 2007)

About the seats being filled, have you ever voluntarily sat at the first row of a theater?  And seat #1 is like 'in the middle of nowhere', so people will be scared to sit there as well... That's psychology for you...

About the measurements, they don't look half bad for a first run, actually.

Seat 2 and 3 have a null, that will be hard to do much about, but it's pretty narrow.
The area from 50Hz to x-over will be filled in a bit with the fronts, so don't worry about it. Do some sweeps with the fronts engaged as well.


----------



## brucek (Apr 11, 2006)

> About the measurements, they don't look half bad for a first run, actually


An understatement. 

I don't want to suggest this after all your fine work, but I wouldn't use the BFD at all. Those plots over that area of seating are completely acceptable and don't require equalization. Any minor changes in one position would upset the others. You have a fine average response.

Use REW to examine and tweak the crossover area when you add your mains. Often, you'll need to adjust the sub phase to get the smoothest transition.

My only suggestion would be to consider a larger sub to replace the one you have (don't simply add a second). A 15" sub would fill that room a bit better and offer lower extension.....

brucek


----------



## YW84U (Apr 29, 2007)

brucek said:


> ...... You have a fine average response


Wow, I have to admit I didn't see that coming!!! I was dead certain that I would be suffering some amount of grief due to the sub being stuffed into the corner! I was looking at the first measurements and thought I had a lot of peaks and so forth - wondering where to 'go from here'...


Originally when I laid out the room, I measured off the distances for the seating by placing each of the seating positions along 5ths or 3rds of the length and width (I made a grid of taped lines, kinda what Les Nessman from WKRP would have done :coocoo . I had understood that this would also help with improved response - was there any merit to this?

Here's a snapshot of seat 1 with the mains added and no BFD (taken with the RS SPL last week, not the ECM)










I really wish I were able to go to a 15", but the space is really tight on the stage and I don't even have much wiggle room left. The other options I've left myself is to put another PS-1000 or similar size sub in the opposite side of the stage, or do an IB by using the adjacent room (unfinished laundry/furnace). The thought of lower extension is rather appealing...

When it comes to integrating with the mains, what would be the key things to look for when interpreting the graphs? Is there something that would indicate how much to adjust the phase, or would it be a little more trial and error? One more quick question - once the mains are introduced, would it be too late to introduce a house curve of some flavor?

Thanks again for your responses!!!!!!


----------



## brucek (Apr 11, 2006)

> The other options I've left myself is to put another PS-1000 or similar size sub in the opposite side of the stage, or do an IB


An additional (similar or same) sub will simply add headroom, not extension...... go with the IB, or maybe an SLLT......



> When it comes to integrating with the mains, what would be the key things to look for when interpreting the graphs?


Watch at and around the crossover frequency for dips and peaks. The best method is to take a few measures with a phase adjustment between each measure and look at the 90Hz area (and below and above somewhat) and see which position of phase gives the best results. You can also look at different seating positions also to see if you've messed up......



> once the mains are introduced, would it be too late to introduce a house curve of some flavor?


No problem, but looks to me as though you have an OK house curve there already at most positions. The house curve would require the introduction of the BFD into the system. Personally, it doesn't look like you need one. Why introduce ADC/DAC's, level and dynamic range problems if it's not needed?

More often than not a room will offer up a common resonant peak of various amplitudes over a wide range of listening positions. Even though each listening position offers its own unique response, there can be a common resonance that shows up if you lay all the measures on top of each other using the All Measured or Averaging tabs in REW. Then it's very beneficial to use a BFD to counteract that common mode. You simply don't appear to have that problem with your room (no doubt due to your careful planning). Overall, each position looks fairly good. I just don't see the need to get into EQing your sub when your goal is a decent response over a wide listening area. There are tradoffs to adding EQ. When you don't need it, then avoid it.....

brucek


----------



## YW84U (Apr 29, 2007)

Thanks Bruce! 

I'm still astounded that no serious audio issues arose from the build - I was convinced from the outset that some tweaking would be required. I'm almost disappointed in a way that the BFD is kind of moot :mooooh:, I guess I was secretly looking forward to applying all of the knowledge I was absorbing from the forums here :reading: It's sure good to have a third-party remind you that sometimes you do more harm fixing things that "ain't broke".

If anything, the BFD can still serve as a low-pass for the bass shakers, but boy its sure tempting to start dialing something in for the sub just 'cause "it's there".

I'll post some measurements with the mains when I get back next week, and perhaps lean on you all for some guidance (I've never played with phase before).

SLLT? Thought I was just starting to grasp the concept of IB.....hah! you made me Google :bigsmile:
Just read some quick blurbs on it, and it may be worth looking at in the new year as well (I just don't yet know how to 'fit' one of these into the current design).

...must.... resist......EQ.........


----------



## brucek (Apr 11, 2006)

> If anything, the BFD can still serve as a low-pass for the bass shakers, but boy its sure tempting to start dialing something in for the sub just 'cause "it's there".


Yeah, it can do the shakers LPF for sure. Don't run your sub through the other channel unless you want to add some filters. You can play around and try some filters, but I would suggest you won't be happy at every position.....

The best SLLT thread is Rodnys IB makeover.

brucek


----------



## clubfoot (Apr 12, 2007)

I notice you have a stair well off to the side of seat 4. Ever thought of putting an air tight door there,...it may surprise you?! Not at the top of the stairs, but the bottom.


----------



## YW84U (Apr 29, 2007)

Too late! :bigsmile:










Have a sealed solid-core door at the top already.......I'd originally considered putting it at the bottom, but felt it would interfere with the placement of the surrounds as well as it would make passage more difficult (you'd have to lean/reach down to the doorknob from about the third stair up or so). Twas a bit of a tradeoff ......


----------



## Wayne A. Pflughaupt (Apr 13, 2006)

Nice looking room there, Tom – love the rack. Why oh why don’t they make the BFD in black? :mooooh: If you want something that matches the rest of the gear and don’t mind doubling what you paid for the BFD, you might try to find a Yamaha YDP-2006.

Regards,
Wayne


----------



## brucek (Apr 11, 2006)

Yeah, the BFD is indeed the most overwhelming and garish front panel of any equipment I own. It really screams to be seen. A nice black panel with a dim feature sure would have been nice.....

brucek


----------



## clubfoot (Apr 12, 2007)

YW84U said:


> Too late! :bigsmile:
> 
> Have a sealed solid-core door at the top already.......I'd originally considered putting it at the bottom, but felt it would interfere with the placement of the surrounds as well as it would make passage more difficult (you'd have to lean/reach down to the doorknob from about the third stair up or so). Twas a bit of a tradeoff ......


That explains allot  I also use solid core doors and they work great. Beautiful theatre you have there.


----------



## YW84U (Apr 29, 2007)

brucek said:


> ....the most overwhelming and garish front panel of any equipment .....
> brucek


:bigsmile: Garish is 'the' perfect word!!! I almost thought of painting or powdercoating it myself (who really needs the printing/button labels anyways?), and putting some window tint overtop of the display..

Wayne - ixnay on the Yamaha....I looked at the prices and nearly swallowed my Thyroid :yikes: Plus, harder to justify seeing as Bruce pointed out earlier that my BFD might even be moot at this point :spend:

I'm looking forward to getting back soon and taking a few more measurements. I've managed to create an adapter for the ECM8000 so I can now mount it on one of my camera tripods (too cheap to buy a mic stand) and get it closer to where everyone's ears will be sitting.

I'm very interested to see how the mains factor into the equation, and whether I might look at more/different treatments to improve it just that little bit extra

BTW - Happy New Year everyone, and wish you the best of 2008!!


----------



## Wayne A. Pflughaupt (Apr 13, 2006)

YW84U said:


> Wayne - ixnay on the Yamaha....I looked at the prices and nearly swallowed my Thyroid :yikes: Plus, harder to justify seeing as Bruce pointed out earlier that my BFD might even be moot at this point :spend:


Where in the world are you looking? I got mine off eBay for under $200 delivered. I thought that was pretty good for a unit that sold new for more than $1500... :scratch:

But like you said, if you really don’t need it... 

Regards,
Wayne


----------



## YW84U (Apr 29, 2007)

I only did a quick Web looky, and saw M.S.R.P. $2,239.74 :unbelievable:

And some used Craigslist ones for $500-$600!!

I didn't really look too hard :sad:......... but $200 is certainly a lot easier on the HT budget, though!


----------



## YW84U (Apr 29, 2007)

Alright.....

So I've now taken some full-range measurements using the ECM8000, trying to see how the mains integrate with the sub. These graphs also include the BFD in the chain, with some minor filters added.

Seat 1









Seat 2









Seat 3









Seat 4









Seat 5









Seat 6









I hope I have the graph limits set right for the full response... as well, I have these at 1/3 smoothing - is that correct? I'm not sure if I've already stumbled upon some form of house curve or not as well.

Has anyone any feedback or suggestions for any areas that may require some attention? Is there anything glaring that would suggest that I adjust the phase or level of the sub? I'm also still a little unsure if I should setup some BFD filters (different that what I have) to tweak for certain seating arrangements 

Any input is greatly welcomed!


----------



## Ivaols (Dec 29, 2006)

Looking at your graph I would say that the sub is too high in level compared to the mains...

How is this sounding? Do you feel that the sub is integrated?


----------



## brucek (Apr 11, 2006)

I want to sit in seat 4...................

Yeah, when you do full range measurements you need to turn on smoothing to see the underlying trend of the response.

Well, maybe your sub is a bit high, but some like a bit more bass.

brucek


----------



## clubfoot (Apr 12, 2007)

I like seat #4 as well 

Now is a good time to tweak the low end response of your mains and center by adjusting their location and orientation so that they blend in smoothly with the sub.

I would also drop the sub level, but that's just me.


----------



## ktaillon (Apr 3, 2007)

I ran some full range graphs also and received the high level on the sub. I ran test tones to find everything was in order.

I believe the problem is when you run just the two front speakers with the sub. It needs to be kicked down about 10db( which I do for 2.1 music listening.)

I ran another full range set of graphs but set the receiver to output to all 5.1 speakers. The levels are right on the money, the graph shows correct level throughout the full range.


----------



## YW84U (Apr 29, 2007)

ktaillon said:


> I believe the problem is when you run just the two front speakers with the sub. It needs to be kicked down about 10db( which I do for 2.1 music listening.)


I think that this may be the case - I recall when I did the check levels, that it seemed off and I had tried turning down the input from the mic but had ended up returning it to the original setting......... I should take some full range ones without the BFD and drop the sub level a bit and see what they look like. Weekend project! :bigsmile:


----------



## Wayne A. Pflughaupt (Apr 13, 2006)

YW84U said:


> I only did a quick Web looky, and saw M.S.R.P. $2,239.74 :unbelievable:
> 
> And some used Craigslist ones for $500-$600!!
> 
> I didn't really look too hard :sad:......... but $200 is certainly a lot easier on the HT budget, though!


Here ya go, Tom. 


http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=180209928776&ssPageName=ADME:B:SS:US:1123 

Regards,
Wayne


----------



## YW84U (Apr 29, 2007)

Thanks for thinking of me Wayne!! Alas, methinks I may have a tough time flying that one past the Ministry of Finance & Household Effects though.......perhaps as time passes, I might be able to Adopt-a-Yamaha :bigsmile:

I've still yet to get around to doing some more measuring/tweaking....my plan tomorrow is to address the rest of the rack (and hopefully subdue the garish-factor of the BFD). I picked up some 1/16 aluminum yesterday, and will attempt to make some custom black faceplates for the racked equipment. Hopefully, the BFD will hide a little better in a sea of black :daydream: I'm curious as to whether closing off the face of the rack will have any acoustical impact. I've also been wondering if adding some bass trapping in the equipment and storage areas would add any benefit as well....

Cheers,


----------



## DrWho (Sep 27, 2006)

To properly integrate the sub and mains, I do three measurements...
1) Sub Only
2) Mains Only
3) Sub + Mains

Using the tab that shows multiple measurements at once, you want to find where the 'sub only' and 'mains only' responses overlap. At this frequency, you want the 'Sub + Mains' to be +6dB. 

So ideally, the sub and mains cross each other at 80Hz and both are 6dB down at 80Hz. The Sub + Mains should measure 0dB down at 80Hz...if not, then you need to adjust the phase/time-alignment of the subwoofer in order to maximize the +6dB.

If your subwoofer's volume is set too high, then the acoustical crossover point is going to move higher in frequency. So even if you set a 80Hz crossover point in the receiver, it's possible for the acoustic responses to cross at say 100Hz or even 150Hz depending on how much you've got the sub cranked.

But ya, the same rules always apply...adust the phase/time alignment until you get +6dB at the acoustical crossover points - even if it doesn't result in a "flat" response. Acheiving a flatter response is better done by moving the crossover frequency around.


----------

