# REWing the Cinemar Theater



## mcascio (Dec 5, 2010)

I'm looking for some guidance from the pro's. I'm openly in the dark on this new venture into REW.

I believe I've calibrated everything properly.

I set my Onkyo to Direct mode with just the F, L and SUB playing while running this sweep.

I'm just interested to see what these graphs actually mean and what I can do to improve the room acoustics within the existing design of the room.

My current build thread is located here:
http://www.hometheatershack.com/for...cinemar-home-theater-construction-thread.html

Thanks for any input you guys can provide.


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## cuzed2 (May 18, 2011)

Mario,

I'll be following along to see If I can also learn - hope you don't mind 
I tinkered with REW last year, and have probably forgotten more than I had learned.

(P.S> believe we have spoken in the past on AVS, I'm your neighbor from that corrupt county just south of your location, Cook Co IL)


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## Wull (Apr 7, 2010)

Can you run 3 sweeps, one for each speaker and Sub separately?

By the way, you have an amazing cinema.....


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

mcascio said:


> Thanks for any input you guys can provide.


Unfortunately we can’t tell much from your frequency response graph because its vertical scaling is too expansive – see here:

Getting Graphs Ready to Post

As far as room acoustics, we have a separate Forum for that. You’ll get better advice than we can provide on this Forum.

Regards, 
Wayne


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## ahmed sihabudin (Dec 11, 2010)

anybody can help me please?
I used Lu7R0n SL-4012 SL meter. how to calibrate this SL Meter?


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## Zeitgeist (Apr 4, 2009)

ahmed sihabudin said:


> anybody can help me please?
> I used Lu7R0n SL-4012 SL meter. how to calibrate this SL Meter?


I'd recommend creating a new thread; You'll get more responses.


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## NotBananas (Apr 4, 2012)

Back in my younger days of the 60's when I just started in audio, the first thing I learned is to get the frequency response of the speaker in an anechoic chamber (see: http://en.wikipedia.org/wiki/Anechoic_chamber) that the manufacturer sometimes furnished. Fortunately in those days we only had to deal with one pair of speakers. The purpose of this is to get base performance of the individual speaker system, when mostly only two way speakers (woofer & tweeter) existed, without any interaction from it's environment. Basically this was to get the resonant frequency and the frequency response of them.

Obviously everyone knows (or should know) that the environment has a huge role in the way the sound is heard. This is due to an infinite number of factors such as room resonance, reflections, interactions with other speakers, furniture, your listening location, external noises, etc.

I constructed many speakers of different types and sizes: bass reflex, acoustic suspension, horn loaded, electrostatic (yes I made my own using Saranwrap and it worked), etc. These efforts further reinforced the fruitless quest for the absolute sound (no reflection of the magazine of the same name) that everyone was striving for.

In the next 50 years (has it been that long?) I came to the conclusion that no matter how many measurements you make, no matter what type of speakers you have, no matter where they are positioned, no matter what's driving them (tubes, MOSFET solid state, hybrid, etc.) there's no way to guarantee the sound will be ideal and what you like.

This is because of the infinite combination of everything making up the total sound experience.

The reason for the long comments above is that no matter what type of measurement system you use, no matter how many charts and graphs you create, it's has only a minimal effect to improve the sound experience using these tools. They may give you pretty waterfall graphs, log charts of the frequency response, etc. but none of these have anything to do with the sound you are going to be happy with. Having gone through all of this myself using the scientific methods of trying to get the ultimate sound and then failing to achieve Nirvana. All the efforts and expense may have helped in identifying some areas needing improvement, like standing waves in a particular spot (but it's only at one test frequency), dead spots, etc.

As a result of all these years of experimenting, rather than trying to scientifically establish what should be, I kept adding a little to the speaker system over a period of a year, tweaking all the positions, and letting my Yamaha receiver decide the correct setting for each one. Note that all the subwoofers have a built in amp, not sucking power from my receiver. Now my HT room has a total of 19 speakers as shown below:


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## HTip (Oct 10, 2011)

As Wayne said, the graph is not quite right, but what I can tell from these is that the volume of your subs is too low. Without subs you should try to get a flat response between 80 (depends on x-over) and 200 Hz set at 75dB.

For correct response with the subs the correct order is placement (in your case not an option ), timing (distance to sweet spot, depends on sub having DSP or not), phase (best SPL output and you cannot tell where the subs are) , level (volume of the subs should also have an average of 75dB) and optionally EQ/DSP.

Look forward to your next graphs...


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## Barleywater (Dec 11, 2011)

Basic response and waterfall is fairly typical. Response <40Hz shows total lack of bass extension. Peaks and dips >40Hz is classic boundary/room mode behavior. Tweaking speaker location, listening position, EQ and possibly room treatments can smooth this out.

Regards,

Andrew


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## mcascio (Dec 5, 2010)

Sorry guys. Just getting caught up. Chris from M&K was kind enough to spend 2 hours with me on the phone to help setup my Onkyo for better more accurate room measurements.

Here are the results from just the subs one at a time.


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## Barleywater (Dec 11, 2011)

Looks like classic sub with no bass extension and usual boundary interactions/room mode behavior using default 500ms IR window. Don't fall into those narrow deep notches, fixing them is highly over rated; to see this try measurements with microphone at different locations, such as in middle of room, or an inch from the floor near a wall. This will build some perspective. Also try IR window of 50ms.

Without bass extension EQ, sub isn't delivering nearly what it is capable of.

Regards,

Andrew


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

That’s honestly some of the worst response I’ve ever seen from corner loading. It’s not unusual to see a null or two (i.e. narrow and deep), but not a whole slew of them like what you’re showing. Not to mention (as Andrew noted) really poor extension for subs of this caliber. Are their openings in the wall near those corners? Can you show us a floor plan or pics of the room?

Regards, 
Wayne


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## hjones4841 (Jan 21, 2009)

That looks more realistic. When I saw your first graph, assuming that you had calibrated REW's SPL meter, I thought the volume was too low and the graph might be showing HVAC fan blower noise.

Be sure to visit our Home Audio Acoustics forum for advice on adding room treatments - they make a lot of difference, especially bass traps.


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## paulspencer (May 11, 2007)

I'm a little surprised by the comments. Aren't we talking firstly about an already treated room? With traps already built in?

Your waterfall plot indicates that the room has some damping already. I'd be interested to see the 2D decay plots, specifically in a similar manner to what I showed here:

http://www.hifizine.com/2011/06/bass-integration-guide-part-1/

Given that you have the bass set flat, I expect you would find it to be a little lean. Normally it sounds better with a house curve where the bass runs at a higher level, and this is especially true in a room that is well damped in the bass. You are also lacking some extension, which tends to suggest that your sub isn't up to the task. You've invested a great deal in the room, it looks spectacular - perhaps time to look at the sub side of things?

I'd also be interested to see the reverb time plot. But perhaps that's an issue for another area of the forum. If you have another thread, let us know.


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## HTB2015 (Nov 24, 2010)

Just wondering what happened here? I was looking forward to seeing the solution.

-Jared


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## mcascio (Dec 5, 2010)

Sorry Jared.

I dropped the ball. I need to rekindle this. I've just been enjoying the theater for now - plus just got a new projector.

I did fill the lower half of all my speaker columns yesterday with R19 insulation which should make a small bit of improvement in the room hopefully.

I wanted to provide some more details and diagrams to the thread to help those helping me out.


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## HTB2015 (Nov 24, 2010)

mcascio said:


> Sorry Jared.
> 
> I dropped the ball. I need to rekindle this. I've just been enjoying the theater for now - plus just got a new projector.
> 
> ...


No shame in enjoying that theater! Looking forward to the new measurements insulated columns.


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## mcascio (Dec 5, 2010)

Hi Everyone.

I finally picked up UMM-6 microphone...so got around to taking some measurements. I've since also added two more DIY subs to the front of the room:
http://www.hometheatershack.com/for...-dual-dayton-rss460ho-18-flat-pack-build.html

Here are some measurements:


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## dougc (Dec 19, 2009)

Looks like a phasing issue between your 2 subs at 48 and 65 maybe. Could you do some sweeps with each one individually? Is there any possibility of turning one at a 90 or 180 degree angle? Mine looks very similar. I could add a sub to the right rear of the room to smooth those modes, but that directly interferes with our domestic harmony.


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## angryht (Nov 23, 2006)

Just a quick observation, mcascio. I just took a quick look at you responses and I noticed you mentioned you had your Onkyo in Direct Mode. For my Onkyo, SR606, when it's in Direct Mode, it does not send the signal to the sub(s). Again, not sure if it's an issue and maybe your receiver is different, but I know when I was doing some measuring, it took me a while to realize that the signal was not going through the sub.


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## mcascio (Dec 5, 2010)

dougc said:


> Looks like a phasing issue between your 2 subs at 48 and 65 maybe. Could you do some sweeps with each one individually? Is there any possibility of turning one at a 90 or 180 degree angle? Mine looks very similar. I could add a sub to the right rear of the room to smooth those modes, but that directly interferes with our domestic harmony.


Thanks. I'll have to run them independently and post results.

I actually have a total of 4 subs in the room now.

My M&K and HSU sub have phase options. I don't believe I can do anything with my Daytons and the Behringer EP4000 amp.


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## mcascio (Dec 5, 2010)

angryht said:


> Just a quick observation, mcascio. I just took a quick look at you responses and I noticed you mentioned you had your Onkyo in Direct Mode. For my Onkyo, SR606, when it's in Direct Mode, it does not send the signal to the sub(s). Again, not sure if it's an issue and maybe your receiver is different, but I know when I was doing some measuring, it took me a while to realize that the signal was not going through the sub.


Sorry - I failed to mention. I've actually upgraded to the Denon 4520 about a year ago. Thanks though for pointing that out. I was double checking to make sure whether or not the sub was powered on when doing tests.

I'm using the HDMi port on my laptop with the UMM-6 mic, so I can select the speakers I want to run the sweep on.


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## angryht (Nov 23, 2006)

Good. For me anyway, it drove me nuts until I figured it out; and I thought maybe that would help explain the lack of bass extension in the early posts. 

I also recently got a new UMM-6 but the laptop I currently use does not have HDMI. Good luck and I'll stay tuned.


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## Greenster (Mar 2, 2013)

Mario,
As you know, I have been following your build from day one. In fact you were my first post on here and one that got me so excited about Home Theaters. Thanks. 
It is interesting to see your rooms response. I would expect the HSU to have much better extension. Wow! I am shocked. Also your current DIY sub looks to be much weaker than it shoud be. I cant wait to see what the solution will be to your room. You may have to move your subs to different locations. Have you tested this yet?


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## mcascio (Dec 5, 2010)

Greenster said:


> Mario,
> As you know, I have been following your build from day one. In fact you were my first post on here and one that got me so excited about Home Theaters. Thanks.
> It is interesting to see your rooms response. I would expect the HSU to have much better extension. Wow! I am shocked. Also your current DIY sub looks to be much weaker than it shoud be. I cant wait to see what the solution will be to your room. You may have to move your subs to different locations. Have you tested this yet?


Hi Greenster. Thanks for chiming in. I'm still trying to learn these graphs.

I'm assuming by extension, you mean increase volume levels?

Wouldn't the difference in the graphs be as simple as me adjusting the volume level up on the receiver to produce more volume rather than the levels I did the sweeps at?

I guess what were you hoping to see in an ideal room that the Sub graphs don't show?

Thanks for any schooling you can provide.


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## Greenster (Mar 2, 2013)

Mario, I wish I was smart enough to give you advice. Truth be told, I have learned so much from your build that I feel that I would never be able to repay you. Thanks. As far as your room goes with your subs, I was expecting much better bass response. I was shocked at the HSU graph as well as the sub you built. I was expecting a much stronger looking graph. There are guys on here that really know their stuff when it comes to sound. Paul sent a link which explaines it very well. Also Wayne and Andrew really know their stuff. Good luck. I will be following!


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