Speaker Calibration Software

[Humanzee]

So I'm finally getting a surround sound processor and amp. Yeah for me. I told myself after frying my stereo amplifier in college that I wouldn't buy another receiver until I could afford the one that I really wanted. It has been 10 years.

Anyway, many of the home theater receivers out there have self calibration for things like speaker timing and level adjustment etc. Basically you plug a microphone into the receiver and put it in the middle of the room. The receiver then runs through a self test making all sorts of clicks and spectrum sweeps to do a pretty good job of setting up and balancing your speakers etc.

Even after ten years of being frugal I still can't justify totally splurging on the surround sound processor that I'm selecting. There are many features that I don't need and I've opted to save the extra $500 that would have provided this one feature among others. I have a friend with sound level meter, and I will get it set up regardless. But it got to thinking about the way I'm going to be using this.

I have a microphone, I have a computer with a microphone port. I have optical output sending a signal to my surround sound processor. I should be able to use some software in combination with my mic in and speaker outs to generate some test tones, to accomplish essentially the same thing that the higher end self calibrating receivers do. At least you'd think so eh? Maybe adjust the timings and levels a little in the computer to get it right and then transfer those numbers into the setup of the surround sound processor. Or adjust and retest, adjust and retest.

Anybody, know of any such software that can generate tones and listen with a mic to give you some calibration advice? I looked on the web a little but ....

[stanger89]

Originally Posted by Humanzee

I have a microphone, I have a computer with a microphone port. I have optical output sending a signal to my surround sound processor. I should be able to use some software in combination with my mic in and speaker outs to generate some test tones, to accomplish essentially the same thing that the higher end self calibrating receivers do. At least you'd think so eh? Maybe adjust the timings and levels a little in the computer to get it right and then transfer those numbers into the setup of the surround sound processor. Or adjust and retest, adjust and retest.

I assume you're talking about things like Pioneer's MCACC, and Audessy's MultiEQ. To put it very simply, you're going to have a very hard time getting anything close to those with just a PC and a Mic, and it will probably be a lot of work. Further, you'll have to do all the decoding in the PC, and then you'll have to figure out how to pipe all the PC audio through the filter you'd create.

Anybody, know of any such software that can generate tones and listen with a mic to give you some calibration advice? I looked on the web a little but ....

That said, there are a couple things out there, probably the best one is RoomEQWizard. Despite the name, it's really best used as a diagnostic tool, there's a ton of info about acoustics in the REW forums.

You might want to look into a Behringer Feedback Destroyer (or whatever the hot EQ is) to help tame low frequency resonances in your room, REW will be very useful for that.

Vista does have some room correction features built in, but I've no idea how (well) they work.

[Jesse]

Hi,

You did not say which AVR you were looking at, but the Denon AVR-1708 (msrp $499.99) includes the Audessy MultiEQ and mic.

My Denon AVR-3805 is several years old now and I am still extremely happy with it. First class product.

Have fun whatever you decide on.

HTH

Jesse

[samgreco]

Be careful with just pluging in any mic and expecting it to work correctly. All mics are not created equal.

The receivers that come with mics have been calibrated to that model of mic, so it doesn't have to be a perfectly flat frequency response (read cheaper). So if you plug any mic into a PC mic input, how does the PC know what response the mic has?

RoomEQWizard that stanger mentioned is great if you use it with the devices it recommends, like the Radio Shack SPL meters It knows what it is and calibrates accordingly. Plus the software also takes a sample of the raw, unaffected signal, right from the sound card outputs to compare the original to the room.

Finally, I'm old school; in that I believe that the least EQ you use the better, so I always try to do as much with the room first. Then EQ after. You'd be surprised how much difference moving a subwoofer 1 foot can make.

[Humanzee]

Thanks for the responses, My system will be pretty modest compared to what is available out there for the serious audiophile. I picked out an Outlaw Audio 970 7.1 AVR and 7075 Amp combo with some Hsu Research speakers and sub. They are all quite well rated for their price.

Anyway, I was figuring that regardless of the response time from any off the shelf microphone you would be able to calculate the delay for any one speaker by measuring them all. If you measured them all and the minimum delay was 10ms for each speaker well, then you know that your mic has a delay. What would be important would be the difference between each speaker. Correct?

SPL I can get from a borrowed radio shack meter, but again I would figure that you could get a fairly precise measurement of the difference between speakers with a cheap mic even if it was not accurate, I guess it would need to be omni directional though.

As far as EQ settings I'm not sure what if any things I can change. I think I'll just be able to set speakers to Large or Small etc, cross over points and calibrate volumes between speakers. I'll have to download the user manual and check that out but I doubt ill be able to set an EQ curve for each speaker in hopes of getting a "perfect" response curve.

Ill have to check out RoomEQWizard, It looks kinda fun at the least, thanks for the tip. My room is pretty awkward so I doubt ill be able to move my speakers much. Plus the wife has constrained my speaker placement options a little. I should be able to get them reasonably close to their theoretically ideal spots, geometrically anyway. I plan on doing the subwoofer speaker crawl trick to find a good spot for that. But first I need get my components delivered.

I hope that I don't need to get an external EQ. I'm pretty sure this room will sound better than anything I've owned previously so I doubt I'll get to picky about anything unless I just have some awful resonance or something. It's like my HDTV, Its not the best but its sooooo much better than my old tube TV that its hard to complain about its shortcomings.

Thanks everyone.

[stanger89]

Originally Posted by Humanzee

Anyway, I was figuring that regardless of the response time from any off the shelf microphone you would be able to calculate the delay for any one speaker by measuring them all. If you measured them all and the minimum delay was 10ms for each speaker well, then you know that your mic has a delay. What would be important would be the difference between each speaker. Correct?

Not really, the minimum delay would be the time it takes the sound to get from the closest speaker to the microphone. Any "delay" in the mic itself is really immaterial. And you don't need a mic to figure out delay anyway, you just need a tape measure, and then enter the distance in the pre-pro (it calculates delay from that).

SPL I can get from a borrowed radio shack meter, but again I would figure that you could get a fairly precise measurement of the difference between speakers with a cheap mic even if it was not accurate, I guess it would need to be omni directional though.

You really owe it to yourself to get an SPL meter, they're not very expensive and they're just one of those tools it's good to have. On top of that, you can use the RS SPL meter as the mic for many of the softwares out there as there are calibration files available for that meter.

As far as EQ settings I'm not sure what if any things I can change. I think I'll just be able to set speakers to Large or Small etc, cross over points and calibrate volumes between speakers. I'll have to download the user manual and check that out but I doubt ill be able to set an EQ curve for each speaker in hopes of getting a "perfect" response curve.

Probably not with that AVR, but I'm not familiar with it's capabilities.

Ill have to check out RoomEQWizard, It looks kinda fun at the least, thanks for the tip. My room is pretty awkward so I doubt ill be able to move my speakers much. Plus the wife has constrained my speaker placement options a little. I should be able to get them reasonably close to their theoretically ideal spots, geometrically anyway. I plan on doing the subwoofer speaker crawl trick to find a good spot for that. But first I need get my components delivered.

Actually REW is probably a much better/more efficient way to find a good spot for the sub.

I hope that I don't need to get an external EQ. I'm pretty sure this room will sound better than anything I've owned previously so I doubt I'll get to picky about anything unless I just have some awful resonance or something. It's like my HDTV, Its not the best but its sooooo much better than my old tube TV that its hard to complain about its shortcomings.

Thanks everyone.

The biggest reason I brought it up, is because if you want to do anything beyond level matching, there's not much you can do without external equipment. Room treatments and some sort of EQ to tame the resonances are probably the big ones. FWIW, my processor (AVM-20 V2.1) has a single-band parametric EQ, they call it a Room Resonance Filter. Even though it's very limited, especially compared to an Audessy system, it's very useful in taming the low frequency response.

[garyellis]

I bought an RS SPL and used the REW software..both seemed to work great and put out lots of nice pictures..Problem is, I have no idea what to do with the data now...



But, I'm sure its all there for when I read enough to get smarter.

Gary Ellis

[samgreco]

Originally Posted by Humanzee

Anyway, I was figuring that regardless of the response time from any off the shelf microphone you would be able to calculate the delay for any one speaker by measuring them all.

It's actually the frequency response that I was talking about. As stanger said, a tape measure is as accurate as anything else for delay times.

I thought you were looking for a way to EQ or treat the room.

As for the gear, while it may be modest in price, the Outlaw stuff is quite good. As is the Hsu sub.

If you get the RS SPL meter, download RoomEQWizard. It really will tell you everything you need to know as far as room modes to correct low end stuff. Which is where the bulk of audio problems are.

[Menehune]

Two cars ago, I purchased a CD with audio sweeps on it. I think is was Bass outlaws or something...lots of warnings about "possible equipment damage due to loud, low freq bass sweeps, etc". That CD had sweeps from 20k-20 and I just tuned my car EQ and bass amp by ear. Run the sweep and adjust to have equal volume during the entire sweep.

An installer friend could hear a speaker with reversed phase and corrected it-I never could hear the phase inversion.
He also showed me a trick to place the sub. Put the sub in the listener's seat, play a bassy CD and crawl around finding the location where the bass is loudest. Move the sub to that location and the lows will be loudest in your preferred listening location. Don't know how well it will work in a home environment, but it sounds logical to me.

[stanger89]

Originally Posted by Menehune

An installer friend could hear a speaker with reversed phase and corrected it-I never could hear the phase inversion.
He also showed me a trick to place the sub. Put the sub in the listener's seat, play a bassy CD and crawl around finding the location where the bass is loudest. Move the sub to that location and the lows will be loudest in your preferred listening location. Don't know how well it will work in a home environment, but it sounds logical to me.

Thing is, you really don't want to place the sub where it will be loudest, or at least you need to be careful with what you mean by "loud". Placing the sub where it's "loudest" will probably be in a location where it's exciting a room mode. What you really want to do is use a track with good bass "sweeps", and position the sub so that no individual notes stand out or disappear.

[Humanzee]

Originally Posted by stanger89

You really owe it to yourself to get an SPL meter, they're not very expensive and they're just one of those tools it's good to have. On top of that, you can use the RS SPL meter as the mic for many of the softwares out there as there are calibration files available for that meter.
Actually REW is probably a much better/more efficient way to find a good spot for the sub.

Yeah, I was reading about using the RS SPL with REW in the online manual. I should probably get one too, but its a good excuse to bring a friend over to tinker.

Originally Posted by stanger89

The biggest reason I brought it up, is because if you want to do anything beyond level matching, there's not much you can do without external equipment. Room treatments and some sort of EQ to tame the resonances are probably the big ones. FWIW, my processor (AVM-20 V2.1) has a single-band parametric EQ, they call it a Room Resonance Filter. Even though it's very limited, especially compared to an Audessy system, it's very useful in taming the low frequency response.

I'll have to see how it sounds before exploring beyond level matching. I'm quite sure that the esthetic in this room is more important to the wife than accoustics. We'll end up with an area rug and maybe some additional curtains that will knock down on all the hard surfaces but I know this room will not get anything beyond that. I have only about 6 different places that I can put my sub, so it should be a quick process of elimination. As far as parametric EQ's at this point I can only leave some room in my media cabinet for one as a later upgrade. I think more effort will go into the theater room when/if ever that happens.

Ill probably get the SPL meter anyway and hook it up to experiment and learn, it will make it that much easier later when setting up a higher end system.

[Humanzee]

Which SPL is preferred, the analog or digital? I would think that maybe the analog would be a little easier to read. Any opinions?

[stanger89]

I haven't tried the digital one, but the analog one is kind of nice because you can easily watch it bounce (and thus determine yourself what the average is).

Personally though, I've upgraded to a Galaxy CM-140 meter, it's supposed to be a lot more accurate, and especially for using with REW, it's got a much better frequency response. Also handy, it supports lower measurements, and the min/max function it quite informative if nothing else.

For the price, I'd probably get the CM-130 over the radioshack model:
http://www.musiciansfriend.com/produ...ter?sku=421161

Or if you're going to want to take measurements, it looks like you'll want the CM-140.