# PERFECT SOUND



## marty1 (Jun 29, 2010)

I am not sure if anyone has achieved this or if it is possible but I was wondering, if you used REW and the results were literally perfectly flat from the lowest lows to the highest highs, does this mean that this is perfect sound?

I am not technical minded I just know the flatter the better.

Is this possible to achieve and does this result mean your sound cannot get any better?

Would really love to know if it is a clear cut as that to achieving perfect sound.

Thanks
Marty


----------



## Sabby (Nov 10, 2008)

Perfect sound is individual. It is whatever you enjoy.


----------



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

Well, it’s a kinda a moot question, since ruler-flat response is impossible to obtain with an acoustic measurement. In addition, ruler-flat response sounds bad to most people. Response that has a gradual rise in the bass frequencies typically sounds better.

Even if perfectly flat sound were attainable, it wouldn’t necessarily result in perfect sound. For instance, stereo imaging is a major factor for excellent hi-fi sound reproduction. It’s audible but there’s no measurement for it. And there are there are things like the quaaality of the drivers that come into play. You can’t measure things like the sheen of a cymbal or hand bells that a first-class tweeter will deliver, because measurements don’t adequately capture harmonics, overtones that the ear can easily hear. Harmonics, subharmonics etc. are generated by voices and musical instruments, and speakers can reproduce them to a great extent, but they are not present in the sine wave, pink noise etc. test signals used to procure frequency response measurements. 

Regards,
Wayne


----------



## marty1 (Jun 29, 2010)

So I take it REW is more for just making minor adjustments and finding out where the major nulls and peaks are?

I will start room treatment soon to get rid of slap echo and I was wondering whether to keep using REW to find out what frequencies I need to attend to flatten but really I guess the major part is done through the trained ear?

I can tell if it sounds too boomy or too lifless in the bass area or too much treble but that is about it.

I have spent quite a lot of time moving the big sub around an inch at a time and measuring, it is very frustrating and time consuming as there always seems to be a peak or a null where ever I move it to, so is it a bit too much to try and get flat response from sub, will I really notice the major difference in sound or is it minimal, would I be better off just leaving it where it doesn't sound too boomy or too weak and leave it at that?

Thanks
Marty


----------



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

> So I take it REW is more for just making minor adjustments and finding out where the major nulls and peaks are?


REW only shows where the peaks and null are. It does not make any adjustments. That must be accomplished by the hardware.




> I will start room treatment soon to get rid of slap echo and I was wondering whether to keep using REW to find out what frequencies I need to attend to flatten but really I guess the major part is done through the trained ear?
> 
> I can tell if it sounds too boomy or too lifless in the bass area or too much treble but that is about it.


 This thread has a lot of good info on the goals and implementation of full range equalization.




> I have spent quite a lot of time moving the big sub around an inch at a time and measuring, it is very frustrating and time consuming as there always seems to be a peak or a null where ever I move it to, so is it a bit too much to try and get flat response from sub,


Try using REW’s real time (RTA) feature. You can see the changes in response on screen as you move the sub. I.e., you don’t have to stop and take a fresh measurement.




> will I really notice the major difference in sound or is it minimal, would I be better off just leaving it where it doesn't sound too boomy or too weak and leave it at that?


Typically we put the sub in the location that gets the best response, then parametric EQ from there.

Regards,
Wayne


----------



## Airdyne (Dec 20, 2010)

marty1 said:


> I am not sure if anyone has achieved this or if it is possible but I was wondering, if you used REW and the results were literally perfectly flat from the lowest lows to the highest highs, does this mean that this is perfect sound?
> 
> I am not technical minded I just know the flatter the better.
> 
> ...


A flat frequency response is merely a yardstick for loudspeakers during test -- as soon as these are placed in any living or listening area - the response is usually like a donkey's hind leg!
Many other factors affect the sounds you end up hearing apart from the loudspeaker and it's interaction with the room. Take for example a live musician playing the piano in a anechoic or sound dead room, the sound he will produce will be different if he plays the same music in a domestic room.
We can only try to obtain distortion free recordings, pure or distortion free loudspeakers, amplifiers and any other equipment in the chain.
Sadly many modern CD recordings are fit only for use as frisbys, whilst a few manage to be refreshing to hear ( try listening to good live FM concerts or downloaded Flac codec music )
So -- here we have a situation where we will try to afford the best (to our individual ears) amplifier - valve or transistor/speakers/CD player/Turntable/DVD - etc,etc 

Room adjustments - positioning of speakers and/or furniture, carpets --- should be experimented with --- however many rooms will exhibit prounounced bass around 60-100Hz -- so a flat response is a worse case situation ----- wheel in the graphic equaliser!!! A good way to shape your response to suit the room!!!

Alas we can only approach near perfection as we perceive it!

Airdyne


----------



## tcarcio (Jun 27, 2007)

Well I find it depends on the source that you listen to and it isn't going to be "perfect" with all of them. I have some music I listen to and it sounds great and then I put something else on and it doesn't sound as good. I guess what I am trying to say is that for me it is an on again off again situation and no matter how hard I try to make it "perfect" I don't think it will ever happen. Just my 2 cents.


----------



## Kenneth R. (Oct 20, 2010)

perfect sound is the grail of music. It doesn't exist but we seek it anyway.

REW will help you find where you can improve your sound with EQ, speaker positioning, and acoustic treatments


----------



## aceinc (Oct 24, 2006)

I haven't tried this yet, but it seems to make sense;

Place the sub in the listening position, and then use an SPL meter and go to the spots that you can aesthetically, or logistically place the sub (while playing low freq's of course) and measure for the highest volume.

Then tune using REW & BFD.

Paul


----------



## marty1 (Jun 29, 2010)

Wayne A. Pflughaupt said:


> REW only shows where the peaks and null are. It does not make any adjustments. That must be accomplished by the hardware.


Sorry Wayne I didn't make that clear, I know REW doesn't make adjustments, I just meant that it can show you what hz level there is a problem with and by moving the sub or adding room treatment you can try to iron out the null or peak (adjustments was wrong choice of word).



aceinc said:


> I haven't tried this yet, but it seems to make sense;
> 
> Place the sub in the listening position, and then use an SPL meter and go to the spots that you can aesthetically, or logistically place the sub (while playing low freq's of course) and measure for the highest volume.
> 
> Then tune using REW & BFD.


I have heard a lot against this, the main reason being is that in order to get an accurate reading the subs driver must be at precisely where your ears will be, with an 11 stone sub this is no easy task 

The spl meter must then be placed at precisely where the subs driver will be near the floor.

How true this is I do not know, it is just what I have read :huh:

Regards
Marty


----------



## aceinc (Oct 24, 2006)

I neglected to consider the title of the thread, "PERFECT SOUND." 

In an imperfect world, getting reasonably close is usually good enough. Considering the size of a bass wave, and that at certain low frequencies the tactile nature requires feeling throughout your entire body, I submit that an inch here or an inch there are not that important. 

Having said that, raising a 154 lbs sub to the listening height, calculating the proper distance from the wall and floor for the spl meter, then placing it in various positions seems easier than schlepping an 11 stone sub all over the listening room and then going to the listening position to test.

Forgetting all of the above, I suspect that the relationship between your room and the sub will allow no "perfect" position for your sub, as there will almost surely be some freq's that are boosted or attenuated from every position that you try (unless you hang it from the ceiling above the listening position:dumbcrazy. If I am correct then you will want to tame the anomalies with some form of equalization. Once you have resigned yourself to this neccessity, then you can allow logistics and aesthetics play some role in the placement, and close will become good enough.

Paul


----------



## ddgtr (Nov 1, 2009)

aceinc said:


> I haven't tried this yet, but it seems to make sense;
> 
> Place the sub in the listening position, and then use an SPL meter and go to the spots that you can aesthetically, or logistically place the sub (while playing low freq's of course) and measure for the highest volume.
> 
> ...


I tried it... It didn't quite work out for me. Raising the sub to the listening position wasn't that big of a deal, however my main problem was I found that the sub must face a certain way at its final position! (I know the lower freq. are not directional). Where I've got it right now it's pretty flat, but if I turn it 45 degrees or more the measurements change considerably. 

I ended up putting some felt pads under it and sliding it on the hardwood floor until I found the best place for it.


----------



## marty1 (Jun 29, 2010)

aceinc said:


> I neglected to consider the title of the thread, "PERFECT SOUND."
> 
> In an imperfect world, getting reasonably close is usually good enough. Considering the size of a bass wave, and that at certain low frequencies the tactile nature requires feeling throughout your entire body, I submit that an inch here or an inch there are not that important.
> 
> ...


This is pretty much what I thought, so even if i was to move the sub to every accessible inch of the room, nowhere will have a flat response.


----------



## RickD1225 (Nov 27, 2010)

marty1 said:


> I am not sure if anyone has achieved this or if it is possible but I was wondering, if you used REW and the results were literally perfectly flat from the lowest lows to the highest highs, does this mean that this is perfect sound?
> 
> I am not technical minded I just know the flatter the better.
> 
> ...


Marty, are you sure you were measuring the sub output? There is no way a graph of the sub output in any room is flat, even with the best equalization.


----------



## marty1 (Jun 29, 2010)

RickD1225 said:


> Marty, are you sure you were measuring the sub output? There is no way a graph of the sub output in any room is flat, even with the best equalization.


Yeah it was sub output, I was just looking at getting as smoother response as possible, I was wondering if a fairly even line within +3/-3db across every range was possible and if that would sound perfect.


----------



## RickD1225 (Nov 27, 2010)

marty1 said:


> Yeah it was sub output, I was just looking at getting as smoother response as possible, I was wondering if a fairly even line within +3/-3db across every range was possible and if that would sound perfect.


If that is the case then be thankful you have a beautiful smooth palette to adjust from to get a "house curve", etc. I am envious.


----------



## aceinc (Oct 24, 2006)

Frequency response is one of the more important criteria, but not necessarily the only one. 

Decay plays a role, I suspect that you could have a flat response graph and still have issues with resonances/ spectral decay where the sound doesn't stop when it's supposed to.

There are other issues and I'm certain others will chime in.

Paul


----------



## cast55 (Dec 30, 2010)

If I measured an absolutely ruler-flat response from the lowest lows to the highest highs, I would suspect a microphone or cabling problem.


----------



## marty1 (Jun 29, 2010)

Just to add something else into the mix, I measure with spl on back of couch with the mic roughly where the middle of my head will be and facing forward.

I measure it there, then I measure again with the mike just an inch or 2 to the left or right roughly where my ears would be and get different responses.

So if I get a smooth response with mike in centre of head position does this mean that I have to keep my head dead still in that position for a whole film  in order to hear the best sound? I very rarely keep my head in the same position for too long?

Regards
Marty


----------



## ddgtr (Nov 1, 2009)

Hey Marty,

I wouldn't worry about that too much. Higher frequencies will start to vary in measurement with the slightest move of the mic. There's not much you can do about it. It will not affect your movie viewing/music listening experience.


----------



## marty1 (Jun 29, 2010)

What about low frequencies?


----------



## Moonfly (Aug 1, 2008)

Low frequencies still vary with the slightest of movement, but a few inches once the system is calibrated wont be anything you will spot as really obvious. There does come a point where you have to accept its as good as can realistically be expected to be and just enjoy the sound. If you find you become unhappy with it, then look at the cause and solution (sometimes the answer is an upgrade, sometimes new decor is the answer). If you find the system makes you smile, all your available measurement data points to a well setup system and your enjoying it, then its time to start enjoying it.


----------



## Dale Rasco (Apr 11, 2009)

I vote we rename the thread from 'Perfect Sound' to 'Unobtainium'. :R


----------



## Moonfly (Aug 1, 2008)

:rofl:

Its not unobtainable though, its just a matter of perception. All we need is a cure to upgraditus.


----------



## Dale Rasco (Apr 11, 2009)

Moonfly said:


> All we need is a cure to upgraditus.


Amen to that Brother!!!!!!


----------



## marty1 (Jun 29, 2010)

Upgraditus needs it's own rehab centre, I will be the first 1 in :dumbcrazy:

I love the sound of my sub but as always, as soon as I think about the uneven line on the response I start thinking I am missing something and for peace of mind, keep on shifting the speakers or sub to try and get the best out of it!


----------



## Dale Rasco (Apr 11, 2009)

:rofl::rofl::rofl::rofl:

I've been doing the same thing since the new speakers came in last week!!


----------



## Moonfly (Aug 1, 2008)

You know, over the last couple years I have managed to get to the point where by I can convince myself the response I am seeing and getting is it. I dont know if that a skill, or a trick of the mind, but I now setup, eq, analyse the results and decide if I can likely better that result or not. Once I decide thats it, I forget about it then.

Only my ears then bring back the onset of upgraditus or obsessive compulsive tweaking disorder. That does happen though, and I have had to buy some new speakers this week as therapy :bigsmile:

I have to say though, I do feel like I took another step closer to that perfect sound.


----------



## Dale Rasco (Apr 11, 2009)

Moonfly said:


> You know, over the last couple years I have managed to get to the point where by I can convince myself the response I am seeing and getting is it. I dont know if that a skill, or a trick of the mind, but I now setup, eq, analyse the results and decide if I can likely better that result or not. Once I decide thats it, I forget about it then.
> 
> Only my ears then bring back the onset of upgraditus or obsessive compulsive tweaking disorder. That does happen though, and I have had to buy some new speakers this week as therapy :bigsmile:
> 
> I have to say though, I do feel like I took another step closer to that perfect sound.


That's funny, I got new speakers this week for the same reason. :T What did you get?


----------



## Moonfly (Aug 1, 2008)

I picked up a pair of XTZ floor standers for the front. I don think they are available in the US, but on e of the reasons I was attracted to them is that they come with a fairly comprehensive set of configuration options with which to tune them to your room. After 3 days and several tweaks, I think I am at the point where I am happy with the response and sound I am getting from them now. If they interest you at all, keep an eye out, I plan to do a user review in the next few days.

What did you pick up?


----------



## Dale Rasco (Apr 11, 2009)

I use the XTZ Room Analyzer so I am familiar with the brand, but don't think there is a distributor in the states yet for the speakers.

I picked up the Axiom Epic 80 7 channel system with the EP800 sub. I'm also gonna do a review soon on them as well. They just flat out kill the definitives I had.


----------



## Moonfly (Aug 1, 2008)

Cant wait for that Dale that kit look pretty serious :T. How do you find the room analyser? If its anything like their speakers in terms of VFM, it should be pretty decent.


----------



## Dale Rasco (Apr 11, 2009)

It is insanely easy to use. Comes with it's own mic pre-calibrated for the system. My only gripe with it is that it doesn't really measure below 16Hz. The new sub goes down to 13Hz...:dontknow:


----------



## Moonfly (Aug 1, 2008)

I think those 3hz will look after themselves and at least they are quite low down the range. Will you include some notes on it in your review?


----------



## Dale Rasco (Apr 11, 2009)

Oh definitely. I plan to do a big review on the entire system and possibly a second review on just the sub. It is definitely a monster. I have already taken plenty of measurements using REW and it definitely hits 13Hz with authority.

BTW, which model XTZ did you get?


----------



## Moonfly (Aug 1, 2008)

You dont read sigs much do you :whistling: :rofl:

Sorry :heehee:


----------



## Dale Rasco (Apr 11, 2009)

Moonfly said:


> You dont read sigs much do you :whistling: :rofl:
> 
> Sorry :heehee:


DOH!!! :doh:


----------



## gdstupak (Jul 13, 2010)

Even if you could get a ruler flat eq response, it doesn't mean that your speakers will reproduce the recorded sound properly.
I have 3 sets of speakers (JBL Studio's, DCM KX's, Bose accousitmass) and can eq them so they are all very close to the same level. But each set sounds totally different.


----------



## Moonfly (Aug 1, 2008)

Indeed, the spl chart is only one small piece of a much larger puzzle. Its merely a guide and a tool used to identify possible problems in a particular area.


----------



## Dale Rasco (Apr 11, 2009)

gdstupak said:


> Even if you could get a ruler flat eq response, it doesn't mean that your speakers will reproduce the recorded sound properly.
> I have 3 sets of speakers (JBL Studio's, DCM KX's, Bose accousitmass) and can eq them so they are all very close to the same level. But each set sounds totally different.


Yeah, it is a night and day difference between the def techs and Axiom's yet their response on the mains is fairly similar. Response definitely doesn't equal quality.


----------



## Benway (Apr 28, 2006)

marty1 said:


> I am not sure if anyone has achieved this or if it is possible but I was wondering, if you used REW and the results were literally perfectly flat from the lowest lows to the highest highs, does this mean that this is perfect sound?
> 
> I am not technical minded I just know the flatter the better.
> 
> ...


I heard one extreme suggestion that goes something like this.

The 25% Subwoofer Positioning: This solution is suggested by Todd Welti at Harmon International: “You shrink the whole room by 25% and put the subwoofers at the corners of that virtual room. Of course you get incredible performance, but that is not practical for most people. But if you use two or four subwoofers in the corners or the wall midpoints, you can get pretty good performance.” 

Don't ask me if it works, or if it is just Snake Oil, and don't blame me if you get a divorce trying it...  Anyway, there is no mention of the listening position? And with subs on the floor and the listeners head somewhere in the middle of the room regarding height, That can hardly correct the height room modes?

It's from this webpage:

http://forum.blu-ray.com/subwoofers/48286-guide-subwoofers-part-ii-standing-waves-room-modes.html


----------



## ddgtr (Nov 1, 2009)

@Benway:

Funny you should mention this... After countless hours of moving the sub around my room and running sweeps and RTAs, I finally came close to a permanent position for it, which happens to coincide with what you just posted above! I am getting the flattest response (both sweeps and RTA) at the listening position, although the actual room corners are about 9-10 db louder.


----------

