# My REW Graph - Leave as it is or try to improve?



## Medrep1 (Apr 29, 2009)

Hi,

After having some advice recently, I have now decided to use my sub for music as well as movies. I therefore re-run REW to get the most flattest response I could.

With reference to the graph, the kit used is a Sunfire HRS12" sub, B&W803D main L&R, and an antimode 8033. Xover is as 60hz, (including centre and rears). Without the antimode the room suffers a huge 15db peak at around 30hz?

I would like to know what your thoughts are on the graph please, and whether it is worth tweaking further? I am a slight novice re REW, but not adverse to learning

The sub is currently placed in a room 4.7mx3.3m, and situated at front wall, between centre and right speaker.

If anything, I would like to up the 40-60hz range, but have tried phase and distance settings but run out of any more improvements? This is where I start to become fustrated and lose the plot......:hissyfit:

The processor is rotel and does not have any form of EQ etc. The result below is from just pure relentless positioning and the antimode 8033.

Thank you for looking.

Regards

David


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## Medrep1 (Apr 29, 2009)

Ooops, here it is!


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## robbo266317 (Sep 22, 2008)

I cannot see your graph. Can you attach it again?

Ok I see it now


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## robbo266317 (Sep 22, 2008)

That's not a bad response except a bit of a peak at 150 Hz.

Why do you want to boost the 40-60 range?


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## Medrep1 (Apr 29, 2009)

Thanks.

I just assumed that the 'punch' is around that region, and that if I could get it a few db higher it should more evident? If you think its a pretty good response then that puts my mind at rest really......

I have managed to drop that 150hz peak slightly with positioning the mains, but lost the graph, but also the lower FR started to suffer slightly. Would you have any suggestions on this, maybe room treatment?

Bottom line is that im a noob who's looking for some reassurance that im not missing out too much musically re my graph?

Thanks!


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## robbo266317 (Sep 22, 2008)

I haven't played around with room treatment yet.
Have a seaerch through some of the other posts eg http://www.hometheatershack.com/forums/home-audio-acoustics/24513-need-some-advice.html


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## glaufman (Nov 25, 2007)

Not a bad response really, but why is it dropping off so much after 200Hz?


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## Medrep1 (Apr 29, 2009)

Thanks for the link. Ill take a closer look later!

As far as the drop off after 200hz, the sweep is set at 250hz max, would this be the cause? Other than that im not sure? Should I set the sweep higher?

My laptop died a few days ago, so after buying a new one yesterday, im currently getting to grips with this new windows 7 business and trying to re install REW and calibrate everything etc?

Ive yet to set the parameters for REW, let alone do a new sweep. Should hopefully have a play around tonight?

If there are any suggestions please tell me!:dontknow:

So the consensus is that the graph is not bad? Good news then!

Thanks.

David


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## recruit (May 9, 2009)

That is a fairly good response David :T and the mains are adding in the 150hz region as they are very capable speakers but with some slight adjustments in positioning may help, boosting is generally not advisable with cuts being the preferred method and that is after you have found the best location for the sub in the beginning.

BTW - nice to see you over here :wave:


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## hybris (Jan 25, 2009)

Have you tried the LIFT25 and LIFT35 features on the antimode to see if that modifies the sound to your liking? You could also try simply increasing the volume on the subwoofer maybe 3dB?


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## robbo266317 (Sep 22, 2008)

hybris said:


> Have you tried the LIFT25 and LIFT35 features on the antimode to see if that modifies the sound to your liking? You could also try simply increasing the volume on the subwoofer maybe 3dB?


Yep, that's definitely worth a go. 

Or you could try Wayne's house curve. (again you will need to search for it, Oh and you need a BFD)


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## glaufman (Nov 25, 2007)

Medrep1 said:


> As far as the drop off after 200hz, the sweep is set at 250hz max, would this be the cause? Other than that im not sure? Should I set the sweep higher?


That shouldn't have that effect. A quick guess might be that you're mains weren't actually running during the sweep, and the sub ws running without the xover engaged, in other words it looks like it could be the top end of the sub's natural response, but that's just a guess.

You could try running a longer sweep, and if the graph comes back up at higher freqs then you know it's a "real" acoustic effect.


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## Medrep1 (Apr 29, 2009)

> That is a fairly good response David and the mains are adding in the 150hz region as they are very capable speakers but with some slight adjustments in positioning may help, boosting is generally not advisable with cuts being the preferred method and that is after you have found the best location for the sub in the beginning.


Great, this is basically what I was seeking, just some reassurance that im going in the right direction. Good to speak to you again, its a small world is the AV one!:bigsmile:

I did try the LIFT options, but they just seemed to excacerbate the rooms 35hz peak. It was to my liking, as it gave me 'more' bass at the bottom end, but I thought the whole point was to acheive a flat response, given the capabilities of the kit???

This then brings me on to a few questions, if I may ask for some further advice?

1) My response drops off at around 18hz, the sub is rated from 18hz onwards. Should I be happy with this, or should I corner load the sub (as per antimode recommendations) to use the room's natural own gain for better LF extension?

2) Should we always aim for a flat response, because after doing some reading I came across the house curve method. I havent completely got the idea yet, but have half a clue! and do I really need a BFD to achieve a house curve?

Bass is pretty good, at around ref level, which borders on uncomfortable SPL levels. Im assuming a house curve gives you that better bass feel through low to high SPL levels. I cannot get my head around this, where we should try to achieve a flat response, but a house curve it totally acceptable:huh:

I know I need to read into this myself, but do others here have their views on house curve vs flat response, and in what scenario what you apply either?

I do find all of this very interesting btw:coocoo::T

Thanks all!

David


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## Medrep1 (Apr 29, 2009)

> That shouldn't have that effect. A quick guess might be that you're mains weren't actually running during the sweep, and the sub ws running without the xover engaged, in other words it looks like it could be the top end of the sub's natural response, but that's just a guess.
> 
> You could try running a longer sweep, and if the graph comes back up at higher freqs then you know it's a "real" acoustic effect


The mains were definitately running? Does it matter if you use the Sub cal tone or speaker cal tone when running the sweep? It was set as full range in the settings menu?

When you say longer sweeps, am I assuming more runs, or at a greater frequency range?

Sorry!:dontknow:

Thanks


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## glaufman (Nov 25, 2007)

Medrep1 said:


> The mains were definitately running? Does it matter if you use the Sub cal tone or speaker cal tone when running the sweep? It was set as full range in the settings menu?
> 
> When you say longer sweeps, am I assuming more runs, or at a greater frequency range?
> 
> ...


No, the sweep is separate from the cal tones. When I say a longer sweep, I mean a greater frequency range.
If we see the grph come back up, then what we see is just a dip... if it doesn't come back soon, then something's wrong.


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## Medrep1 (Apr 29, 2009)

Ok, thanks. I will have a crack later.:T


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## glaufman (Nov 25, 2007)

The difference between desiring flat vs house curve response is largely personal preference.


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## Medrep1 (Apr 29, 2009)

That answers my question then.....!

Seen as it has taken me so long to achieve this reasonably flat response, I think i'll try living with it for a while before tweaking again? The sound is certainly different.

Bass is quite dry and tight, tending to sound more like thuds/bangs rather than booms and rumbles. Im also happy that there is not so much apparent ringing at the listening position, it was making me very uncomfortable. The bass during films now have that 'who's knocking outside' sensation, but not so much of the chair shaking rumble I used to experience?

Its the strange feeling if something missing from the bottom end, and possibly a lack of real sub bass as the sub is now placed mid wall. Originally it was corner placed, with antimode, with no final eq'ing, so god knows what the response was like. Probably a huge peak from sub 18hz to 40hz?

All I want to acheive is to hear what the director intended, but with options of house curves/flat responses etc, its just confusing me more?


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## recruit (May 9, 2009)

Many years ago when I was using a BFD for EQ I did use a house curve as my preferred option over a flat response, but now with my current sub and set up I do prefer a flat response with the sub approx 4-5db louder when setting up with an SPL meter.


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## Medrep1 (Apr 29, 2009)

> Many years ago when I was using a BFD for EQ I did use a house curve as my preferred option over a flat response, but now with my current sub and set up I do prefer a flat response with the sub approx 4-5db louder when setting up with an SPL meter.


I feel this is where I become confused? If I were to measure my REW flat response graph, using an spl meter, then my sub averages around 1-2db's lower than the mains, centre and rears.

If I were to up the db level on the sub, then surely the flat response would be lost, negating all the hard work?

Or am I wrong?


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## recruit (May 9, 2009)

No not really, don't forget your ears are less sensitive to bass at the lower end and is felt rather than heard so it makes sense to up the bass a good few more db to your preference, with a house curve you are deliberately creating a curve to achieve a certain response in room, with a slant from say 20hz to your cross over point.

I always feel that if the sub and speakers are perfectly integrated then a flat response is IMO better, but you can try different curves if you wish for experimenting and then choose which you prefer.


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## Medrep1 (Apr 29, 2009)

Ok. The further irony is that from looking at some graphs of various house curves, my pre eq'd response was very similar, and I had to drop the sub overall by quite a bit to get it level with the mains.

The peak induced by my room from the low end is horrendous, so its naturally giving me that form of curve, just an overly exaggerated one:blink:

I cannot see though how a house curve can be accurate for music? Ill up my sub by a notch and reduce all other channels by the same. I know from memory this will give me a very similar house curve?

Not to go too off topic but im hving real problems trying to get REW enabled correctly on this new Windows 7 laptop?

Is there a link etc that would talk me through it? Im currently trying to calibrate the subwoofer levels (just completed soundcard) and the OS volume is either too much or too little.

Im also having to use a y phono splitter for the 3.5mm jack to stereo phono lead to go into the radioshack spl meter. Before I could just use the red or white phono jack straight into the spl meter?!? If I use just one of the phono's then only one of the PEAK RMS Meters are activated?

Sigh...............lol


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## hybris (Jan 25, 2009)

I would consider putting on some music at what you think is a normal / comfortable listening level, then just increasing the level of the subwoofer (not reducing the other speakers) until things sound right / you think it is enough bass - and then possible reducing it 1-2dB again (it's easy to get carried away). 

Then measure again and see how that looks. I wouldn't be surprised if that end up with a quite decent housecurve. You could also play with moving the crossover up from 60hz to 80hz to acheive the correct curve.

The point of a house curve is to get what is perceived as the correct amount a bass to YOUR ears, specifically at lower levels. Very few people listen at reference levels (it's LOUD), and when you listen to volumes lower than that with a frequency response that measures flat it usually sounds too thin.


And to your question about 18hz response - With a curve looking as good as yours do now, I wouldn't move my sub anywhere, and most people would be more than happy with flat response to 18hz


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## glaufman (Nov 25, 2007)

Judging by your description of changing connections, I'm guessing this is a new computer, not just the new OS?


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## Medrep1 (Apr 29, 2009)

Yes, its a new laptop with windows 7 installed.

I have got as far as calibrating the soundcard, but when trying to calibrate the sub with the SPL meter, only one of the VU meters was activating. I have found a way around this by using a y phono adapter into the SPL meter, so both red and white phone jacks are utilised into the meter, and then the 3.5mm jack end of the cable is going into the laptop. (I hope this is right, as my old laptop use to work with just either the red or white phono input into the SPL meter?)

The next hurdle, if my above step is correct) is trying to calibrate everything between REW and the OS volume control? The Laptops OS volume commands are alien to my last laptop, therefore I cannot follow the guide in the sticky section? 

Basically the sweeps are too low, and I cannot get the balance set up bewteen laptop volume and REW?

Any help greatly appreciated, as im lost and spent hours trying to figure it out?

I know I need to mute certain things and adjust volume with others, but its very confusing?

Thanks!


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## hybris (Jan 25, 2009)

You don't need the y phono adapter. it is okay that only one vu meter is active.

Windows 7 issues: I assume you've found the output volume control (just click the speaker icon on your taskbar). To locate the recording volume you can right click the speaker icon and select "recording devices". This will reward you with the following window:









Now right-click the input device you want to use (in my case that's the one called "Line") and select properties. You will get this window. Select the "levels tab". From here you adjust the recording level.









Also make sure you take a look at the "listen" tab, and uncheck the "listen to this device" setting.








Hope that helps


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## Medrep1 (Apr 29, 2009)

Fantastic, thank you! Just a few more queries if you dont mind?

1) I dont have a 'LINE IN' tab, only EXTERNAL MIC, INTERNAL MIC and STEREO MIX. Im assuming EXTERNAL MIC is equivalent to the LINE IN you show?

2) I also have an additional tab in the LEVELS TAB (mine says MICROPHONE, not LINE?), which states MICROPHONE BOOST. Should this, and the LINE/MICROPHONE volume be set as max?

3) And lastly, sorry, I have options for what sample rate it should be set at. Should it be 2 CHANNEL, 44100HZ CD QAULITY

Cheers:T


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## hybris (Jan 25, 2009)

Medrep1 said:


> Fantastic, thank you! Just a few more queries if you dont mind?
> 
> 1) I dont have a 'LINE IN' tab, only EXTERNAL MIC, INTERNAL MIC and STEREO MIX. Im assuming EXTERNAL MIC is equivalent to the LINE IN you show?
> 
> ...


1) External mic is probably the mic input on your laptop, so yes. It's not all mic inputs on modern laptops that work very well with the radioshack, but if you get proper levels you should be allright.
2) set the level to whatever works while doing the soundcard calibration process as well as the check levels process in REW. 
3) Yes that should work just fine.


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## Medrep1 (Apr 29, 2009)

Thanks for taking the time to reply, much appreciated.:T


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