I need help with my room


Rooze came over yesterday with a TACT room analizer(?) which showed the frequency response of my system in my room. I will try to post pictures of the results, but suffice it to say that the entire frrequency response is muted. I have one spike at about 40Hz but everything is an average of 6db below what it should be.

There are pictures of my system so you can see some of the room, although I have taken down all my room treatments. This did help, but not enough. The room is carpeted and has a cheap acoustic tile ceiling. I was wondering if fire rated tiles would help in the midrange and treble?

Any ideas for getting me to where I should be? HELP!
nrchy

Showing 3 responses by sean

Nate, i'll start off by saying that you are a brave individual. You've laid your heart, soul, system and room along with all of its' non-linearities out for all to see and criticize. Kudo's to you for having the guts to do that. Having said that, i think that most folks would be utterly stunned if they saw the response of their system when obtained from testing like you did. I know i was when i first had access to upscale test equipment. Even just listening to the image shift when playing the Cardas sweep tone told me that something was VERY wrong. The funny thing is that moving over just one foot to either side and playing that same frequency sweep will produce DRASTICALLY different results. As mentioned above, that's why averaging of results becomes important.

In order for one of these devices to work and be properly interpreted, you have to take GOBS of readings. Something that most folks don't understand is that, if the speaker isn't very linear to begin with, you can't compensate for that with room treatments. That's why i've stressed speaker designs that take into account real world room acoustics with typical in-room placements. Most speakers, especially a lot of higher priced "audiophile approved" designs don't do this.

Other than that i don't know if you took any nearfield measurements of your speakers, but you should do that if / when you get a chance. This will tell you how much of what you are measuring is room based and how much is speaker based. As you get further away from the speaker, the room becomes a bigger factor. This is why some folks absolutely love and "preach the gospel" of nearfield listening i.e. less room interaction.

Other than that, your in-room response from appr 125 Hz up to appr 15 KHz varies +4/-5 dB's. This is actually not that bad compared to some that i've seen but could obviously use some help. Once again though, i don't know if you are fighting speaker problems, room problems or a combo of the two ( most likely ).

As to bass response, most rooms look absolutely horrible to say the least. Poor speaker design along with poor acoustics make for VERY "non-linear" response. For a peak at what the measured response is of someone else's system that has taken a lot of time in setting things up, take a gander at Joe's measurements regarding his "Critical Q subwoofer" installation. As a side note, i would encourage those that are interested in learning about woofer design and / or the "sealed vs ported" debate to give this entire article a read. It is quite educational and deals with real world situations and the design goals / trade-offs that we have to deal with.

Back on topic now, Joe's system actually measures quite good, yet it is something like +6/-5 dB's from 20 Hz to appr 15 KHz. It should also be noted that Joe chose to use a very revealing method to test his system, so it would look much "flatter" if he had used the standard 1/3 octave method that many others use.

As such, Nate has nothing to be ashamed or embarrassed about. While his system looks "rough", part of that has to do with the size of the graph used. If we were viewing a smaller graph length-wise with a narrower vertical gradient scale, the in-room response could have been made to look "much better". Obviously, his system isn't perfect and needs work, but the scaling of this graph somewhat exaggerates the results compared to what we are used to looking at.

Having said that, I have a lot of respect for anyone that would have both the guts and humility to post potentially "embarrassing" measurements ( only to those that aren't well versed in actual in-room response measurements ) and then ask for help in resolving those problems.

Not to single him out, and i know that he won't take this the wrong way, but even with the calibre and cost of gear that he's using, one can see how easy it is to end up with a "non-linear" system. On top of that, it is also easy to see how one could have a very different "sonic conclusions" when making comparisons from one system to another. That is, each system is going to produce unique deviations in frequency response ( and associated observations in timbre and transient response as they are all inter-related ). This is why i and many others strive to promote "neutrality" in both electronics and speakers, as a neutral response removes as much of the individual deviations out of the equation from system to system as is possible. Obviously, minimizing the deviations from a "flat" response can be a LOT of work and very frustrating to say the least.

With that in mind, my suggestion is to NOT make any brash decisions until you can make some very thorough tests and analyze the results. That is, IF you ( or anyone else in a similar situation ) aren't happy with what you are hearing. Obviously, some folks are content to listen to what they have and think that it is "as good as it gets" without really knowing what they are dealing with whereas others strive to achieve the best results possible. It would appear that Rooze and Nate are folks that fall into the latter category. As mentioned though, when one first takes steps like this, the "shock to the system" that you get as results may be enough to scare one away from seaking the "sonic grail of neutrality".

If you were to "quit" now and simply enjoy your system, i would understand. At the same time, i know that once someone sees this type of information about their system and know what is going on, it is a hard thing to forget about. As such, i would advise others to NOT take the steps that Nate did UNLESS you have the heart, soul and courage of a warrior. I say "warrior" as you'll have one helluva fight in front of you once you see what you're really dealing with. Sean
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I agree with your post Rooze. That is, enjoying one's system and knowing that it is as neutral as possible are two different things. That's why i said that i could understand if Nate or anyone else in a similar situation "quit while they were ahead". That is, stopped working and spending while they were still happy and not quite as broke.

It all boils down to personal preferences, perspectives and goals. Having said that, i think that doing something like this and then seeing the results is VERY frustrating, dis-heartening and will tend to eat at most folks from the inside out. It's a tough call as to what to do and how to go about doing it. That's why i applauded Nate's willingness to bare his soul in such a public manner and his willingness to ask for help.

Other than that, i agree that he needs to be more specific about what it is he wants to achieve i.e. more neutral in-room response, particular changes to tonal balance, etc... If he's happy with the system but not happy with how it measures, and he pursues the correction of the latter, the system may measure flatter. The question is, will he still enjoy the presentation of the system as much as he does now???

Given that most people think that their system is much "better" or "more accurate" than they think it is, they really don't know what they are getting into when they start looking at the testing of their system in this manner. This type of situation is typically a MAJOR can of worms that most folks are afraid to open. I don't blame them either as it gets very complex.

By the way, while you guys were doing all of this testing, did you use the TACT to as a correction device at all? If so, I have to wonder if Nate preferred the system in stock vs corrected form? I'm sure it sounded VERY different. Depending on which he preferred, that might give him a better idea of whether or not he should "mess" with his system or not. Sean
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Nate: Easy mistake to make when posting on a complex subject i.e. assuming that we know what you know. Other than that, i agree with what you said. That is, you left out just a few "small" details : )

My thoughts are that you would have gotten VERY different results if you would have taken the measurements with your Krell in the system. The high output impedance that Cary amps demonstrate will typically introduce very measurable divergences from "flat" frequency response in most systems. On top of that, those divergences from neutrality will vary in frequency and amplitude with the different loudspeaker / cable combinations that they are mated with. This is not to say that Cary amps don't or can't sound good, but that the results of mating this type of amp with any given speaker / cable interphase is most assuredly a "crap-shoot" at best. With components like this, it is strictly a matter of "system synergy" as the predictability factor based on science is very low.

As a side note, those that own Cary products and think that i'm slapping them in the face / stepping on your toes, please review some of my previous posts where i mention this brand. While i personally believe that Cary amps are not a very "linear" device, they are quite capable of producing very "musical" sound that is highly enjoyable and projecting vast amounts of spaciousness into a recording. Funny thing is, one of my other "favourites" when it comes to mass-produced tube gear would be Atma-Sphere amps, which measure VERY differently from Cary amps. Completely different ends of the sound and design goals spectrum, so go figure... : )

Other than that, if it were my system and knowing what i know now about the test conditions, i would consider the test runs that you did to be nothing more than an experiment and "learning session". If you wanted to do this "right", you really need to get your amp back in there ( or the amp that you intend to use in the near future ) and give it another series of test runs. Sean
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PS... If i remember correctly, Stereophile actually tested a Krell amp in the same issue that they did a Cary amp. John Atkinson said something to the effect of "If one of these amps is right, one of them is VERY wrong". Obviously, it all boils down to a matter of personal preferences : )