How do I know if I need room correction?

Posted by: John Galt

How do I know if I need room correction? - 09/02/12 10:05 AM

So, I'm debating whether my next eventual upgrade move from my 1070 should be to a newer HDMI-capable receiver with decent room correction *or* going towards separates.

At this point I'm considering the Anthem MRX-300, which is in the $1000 range and has Anthem's well reviewed ARC technology for room correction. The receiver's amps are roughly comparable to the 1070's amps, which is suitable for my speakers.

On the separates front, I'd be looking at the upcoming Outlaw 975 paired with the 7075 amp assuming the pair can be had in the $1300-ish price range. I'm not clear on whether or not this processor would have room correction or not.

Is there any way to tell if I would benefit from room correction? For instance, are there test tones that I could use in conjunction with an SPL meter that would indicate sonic holes/dips etc. that if corrected, would result in generally accepted better sound? My setup is in a 12'x10' area of a finished basement open on the back and on one side, drywall walls and ceiling, carpeted floors total area is approx. 30'x25'.

Any thoughts?

Thanks,
John
Posted by: XenonMan

Re: How do I know if I need room correction? - 09/02/12 10:41 AM

No doubt there is a need for room correction for almost any room. Any of the Audyssey products will function very well for most rooms. Keep in mind that although you can set up the room manually with a meter it is much faster and more accurate to use a room correction system. Most of the systems perform many measurements using the calibrated microphone which is more consistent that our ears and much less subjective.
Posted by: sdurani

Re: How do I know if I need room correction? - 09/03/12 05:06 PM

Originally Posted By: John Galt
How do I know if I need room correction?
If you want to hear less of your room and more of the source material then you need room correction.
Originally Posted By: John Galt
For instance, are there test tones that I could use in conjunction with an SPL meter that would indicate sonic holes/dips etc. that if corrected, would result in generally accepted better sound?
Sure, you can download a test tone CD here. Once you graph peaks and dips, you'll have to get some sort of external equalizer to correct them. By comparison, you'd get much better results using a receiver that has built-in automated room correction (like Audyssey XT32).
Posted by: Blind Hog

Re: How do I know if I need room correction? - 09/04/12 09:17 AM

I think Xenon got it right. Every room will benefit from room correction. What drove me to it was inconsistent bass responce in different areas of the room. I had some seats that the bass would drive you out of the room and other seats where the bass was inadequate. That was due to sound reflections coming from the room. No automated electronic room correction system is going to fix that. I bought a kit that contained bass traps for the corners of the room and sound absorbing panels for the walls. After it was installed, it not only corrected the bass problems, it made the whole system sound much better through the full frequency spectrum. It was the single most effective improvement in sound I have achieved. It gave me more improvement that any electronics or speaker upgrades that I have ever done. Once you have a decent system and start upgrading, you get to the point that the sound improvement from the upgrades are quite subtle. The improvement from room correction was not subtle. It was dramatic.

It is my opinion that an electronic room correction systems will help flatten the frequency curve, and will easily set the speaker distances and levels for you, but it will not adequately correct for sound reflections in the room.
Posted by: bestbang4thebuck

Re: How do I know if I need room correction? - 09/04/12 09:18 PM

Concur with Xenon and Blind.
Posted by: Hank

Re: How do I know if I need room correction? - 09/05/12 06:27 AM

+1
Posted by: John Galt

Re: How do I know if I need room correction? - 09/05/12 10:50 AM

Hey, thanks for the input guys. You've swayed me towards valuing a setup that has decent room correction. Let's hope the up-coming Outlaw 975 has that capability.

Sanjay, thanks for the link to the test tones, I'll give those a try to see how the response curve is looking un-eq'd.

Blind Hog, room treatment sounds like the right way to proceed, but it's likely a non-starter for my room for a few reasons...well one primary reason actually ;-)

I don't have the issues with bass inconsistency around the room that you are describing and the sound is generally decent, so hopefully the addition of room eq will just make it a bit better.

I've read in quite a few places that the next step up from a quality $1000-ish receiver would be to go with separates. Any opinion on how significant this step is for a setup mostly used for HT, gaming and background music? My speakers range from 92dB to 95dB sensitivity if that's relevant.

-John
Posted by: XenonMan

Re: How do I know if I need room correction? - 09/05/12 10:25 PM

3 primary reasons I can think of to go with separates:

1) More honest power rating for the amplifiers. Most receivers are rated with only two channels driven at the rated power. Some power amps are rated this way but all of the outlaw amps are "all channels driven" rated so there is more available power.
2) Heat generation aroung sensitive electronics. Since the amp generates most of the heat and it is in close proximity to the electronics in an AVR the life span is likely to suffer somewhat.
3) More electronis noise generated by the power amps again close to the electronics.

Two big reasons to stay with a receiver:

1) Cost. AVRs tend to be less $$$ than separates. Even AVRs with sibling AVPs in the same lineup are not as expensive as the AVP when you factor in buying the amp.
2) Many more choices and most have all the bells and whistles that AVPs sometimes lack.
Posted by: gonk

Re: How do I know if I need room correction? - 09/06/12 02:37 PM

Originally Posted By: XenonMan
3 primary reasons I can think of to go with separates:


That's a good list. I could see some people adding a fourth reason to the separates list:

4. Upgrade path. You can get a really good amp and keep it for many, many years, upgrading the processor portion with newer processors (or even receivers used as processors) as features change.
Posted by: Hank

Re: How do I know if I need room correction? - 09/07/12 06:27 AM

+1 Don't most of us Outlaws have separates?
Posted by: bestbang4thebuck

Re: How do I know if I need room correction? - 09/07/12 10:51 PM

Any amplifier utilized for full-range work must provide substantial power for low frequencies while also providing clean and fast transients for high frequencies. Outlaw amps do this well, likely better than most AVRs.

However, if one wishes to use HDMI audio and/or meaningful electronic adjustment to aid in room correction, one would need something other than an Outlaw product to take on the processing duites.

I think almost any AVR will benefit from some reduction in 'power burden' by at least sending the lowest frequency power demands to a powered subwoofer or separate amp/sub combo; fast transients would not have to ride on top of the largest power fluctuations. If one uses a separate power amp (with or without a subwoofer taking on the lowest frequencies) the power stage of the AVR may still be following the voltage of any non-subwoofer freqencies, but the AVR is not trying to deliver strong current or fast transient changes in current, and the AVR power supplies are practically coasting.
Posted by: John Galt

Re: How do I know if I need room correction? - 09/18/12 09:34 AM

Thanks for the information. I'm still on the fence as far as moving to separates but did have another question re:

Originally Posted By: bestbang4thebuck
Any amplifier utilized for full-range work must provide substantial power for low frequencies while also providing clean and fast transients for high frequencies. Outlaw amps do this well, likely better than most AVRs.


Is the 'substantial power for low frequencies' applicable to speakers with a high sensitivity as well? My floorstanders have 10" woofers with a rated sensitivity of 95dB and a power handling rating of 250W...would they benefit from 'substantial' power (i.e. 200W vs 60W)? I use a 60Hz crossover for HT usage, but run them with a full-range signal for stereo listening.

Thanks,
-John
Posted by: XenonMan

Re: How do I know if I need room correction? - 09/18/12 10:48 AM

95 db is pretty efficient. Most music does not have content that goes lower than 40 hz so you are probably fine with the power you have for music. HT is another matter. There is usually some content in movies which goes down into the 15-20 hz range which requires a lot more power to move the amount of air. Bear in mind that in doubling the power to a speaker increases output SPL 3 db. Your speakers are capable of 95 db spl at 1 watt. At 60 watts they would be at about 112 db (log2 60 times 3db plus 95db) which is pretty loud. At 200 watts input you would have about 117 db spl. Also bear in mind that these numbers are all lab/ideal numbers and depending on your room you may not get to these levels but it is all scalable to your room. Most of us want big clean sound and in order to get it at the lower HZ we use a subwoofer powered by a separate amp. It provides plenty of LFE and relieves the main amps and speakers from having to supply the power which gives more available power to the mains. IMHO if you are running a receiver with 60 watts per channel and you are using a powered sub with your mains 95 db efficient you have plenty of power.
Posted by: John Galt

Re: How do I know if I need room correction? - 09/19/12 09:16 AM

XenonMan,

Thanks for the reply. I didn't realize the sub-40Hz frequencies required 'gobs of power' regardless of a speaker's rated sensitivity.

The Outlaw 1070 I'm currently using has enough of power for my tastes. I did take some measurements a while ago to see how loud it could play cleanly, I believe it was somewhat in excess of 110dB --- yes I did have ear protection on and it was for a very short period of time smile So, yes, an honest 60wpc ought to be plenty.

It's good to know that something along the lines of the 7075 amp would be sufficient as well if I go the separates route.

Back to the waiting game...

-John
Posted by: EEman

Re: How do I know if I need room correction? - 09/19/12 11:18 AM

As a point of reference:
My room is approx 12' x 18'
My Aperions' efficiency is 87dB and present a 4 Ohm load at some frequencies
I'm running a 970/7075 combo and it's more than loud enough although for some sources I get within 10 dB of maxing out the volume knob on the 970.

BTW my sub has a 250Watt plate amp and it's using most of that
Posted by: XenonMan

Re: How do I know if I need room correction? - 01/18/13 12:01 AM

Gonk where are you??? Have you given up the forum altogether. We miss your sage advice.
Posted by: gonk

Re: How do I know if I need room correction? - 01/19/13 01:26 AM

Originally Posted By: XenonMan
Gonk where are you??? Have you given up the forum altogether. We miss your sage advice.


You rang? I haven't given up the forum entirely, but have been struggling to find time to put brain power into the hobby. Some of it is family obligations, and some is work load. Case in point: I'm approaching two months behind schedule getting a review of the BDP-105 written, and my interest in hearing a Model 975 has not been sufficient to lead me to pick one up to tinker with (partly because it wouldn't be able to pair up with the BDP-105's multichannel analog output and partly because I haven't even had time to fix a random IR distribution glitch in the system, much less tackle a SSP change-out).
Posted by: XenonMan

Re: How do I know if I need room correction? - 01/19/13 02:22 AM

Gonk, your soul belongs to the gods of AV everywhere. So far the 975 is getting pretty good reviews elsewhere but there seems to be an issue with the maximum volume output in some systems. Not sure if it is a real issue or a setup problem.