Frequency Response vs Listening Room vs Crossover Impact on Sound Quality

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HAL

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Tyson,
Thanks.  Hope it helps.

Now back to making HAL MS-6 Music Servers that let folks make room measurement as part of its capabilities.  Fun times indeed!

Rich

DaveC113

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IMO, it's more complicated than that as you have to consider the human element. Toole went into this in some detail in the video I'm 100% sure Hal and Danny have watched... ;)

The real impact of what Toole said about our psychoacoustic processing of sound in a small room, is that the room might matter a little less, and how much it matters is surely not linear.

Consider an ideal room, doesn't matter what it is exactly... you can deviate from ideal to some extent before it matters much. Then, how much it matters depends on how much the deviation impacts psychoacoustic processing of the sound. In other words, there are some deviations from ideal that matter and others that don't matter as much. If the room is "familiar" to our brain acoustically, it will be able to separate the sound of the system from the sound of the room to a greater extent.

I'd argue that if you have a system in a room, and the acoustics are not distracting, then the system matters WAY more than the room. If you have a bad room, no system is going to sound great. Of course, this is also an oversimplification, but I think it's a little more accurate than a blanket statement that the room is most important. It is only most important if it's getting in the way!   

So in the case the room isn't really causing problems, the crossover quality is MUCH more important.

Similarly, I don't think FR is quite as important as long as it's close and not a distraction.

Tyson

I agree, our brains are wonderfully adept at filtering out a good portion of room acoustics.  So we can still hear good sound in an average room.  But, having had both good rooms and bad rooms myself, it's so much less fatiguing to listen to a great system in a good room.  I think it's because when we're in an average (or bad) room, or brains have to work extra hard at trying to filter out the effects of the room.

When you improve your room, you are literally giving your brain a break. 

HAL

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If you are referring to this talk that Toole gave in 2015, I do not see any inconsistencies in the earlier discussion here:

https://www.youtube.com/watch?v=zrpUDuUtxPM

EQ below the Schroeder room frequency works.  He shows it as below 150Hz for a small room volume which depends on the specific room size. 

EQ for resonances is being used in the JBL M2 speaker quite a bit from working on a new DSP version of that crossover for the dspMusik 2x8 system.   A very nice document of how the M2 crossover works is online.  It needs a lot of EQ.

The Spinorama 70 measurement test being referenced can also be done by a newer system called Klippel.  Relatively expensive, but cheaper than a large anechoic chamber.

He did not say that speakers sound good in all rooms.  He just said they were judged consistently in that context.  At the very beginning he says that listening rooms can sound very different.  Setup of speaker in the room is key to their sound.  Below the Schroeder frequency the measurements do show what you would expect. 

He also did not say that EQing dips up works, but peaks EQ'd down does work.  Same as a passive notch filter to deal with a speaker driver resonance that exists.

He also said that musical recording variability is huge, so using them to judge speaker setup requires many recordings. 

77SunsetStrip

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Rusty,
Yes, and if you unwrap the phase of an FFT of the test signal as REW will do, the phase response of the speaker can be seen and compared to others with the room removed if done as a gated time measurement.  There is a check box in REW to see it. 

If I am correct that you mean the phase that can be displayed with the FR plot, compared the two.  In the leaning mode with REW.  The 1996 vintage with upgraded crossover phase is a fairly smooth line with no abrupt changes.  The 2005 vintage phase has several abrupt changes. 

Before delving deeper into the technical area, would like to clarify and provide more information.  I appreciate all the comments.  Maybe not possible, but would like to keep technical details as high level as possible appropriate for the average audio hobbyist.

Back to phase.  In general, I would think abrupt changes in the phase plot could indicate a problem?  Room or Speaker?

The two sets of speakers are different brands.  Prefer to keep the brand out of the discussion, like a blind test.  I will say the 1996 vintage design is known for superb imaging.  The 2005 vintage is from a company with a 50+ year history.

The videos Danny posts about "fixing" speakers sent to him inspired me to upgrade the 1996 vintage crossovers.  Original component wise, film capacitors, metal film resistors, hand wound iron core inductors.  A couple "audio grade" electrolytics the designer recommended replacing with good poly caps.  The upgrade was all poly caps, air core inductors, and better quality resistors.  Also installed tube connectors.  Big improvement approaching the speakers disappearing.

The 2005 vintage crossover is all stock, borderline cheesy.  Pretty much falls in line with what Danny talks about regularly.  Pretty good drivers, most of the cost in cabinetry, and the crossover is cheeeeep.  However, published and confirmed in reviews a darn close to ruler flat FR.  With more listening time and placement tweaks, a little more life. My yardstick for comparison are several live recordings.  The 2006 vintage are not bad by any means.  For my room and my ears definitely clean and accurate, but does not convey the "live" of live recordings. 

Agree, room is a big factor.  Much in the way of treatment is just not in the cards.   

Think the only way to satisfy my curiosity is to upgrade the 2006 vintage crossovers. 
   



HAL

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If the phase of the measurement has been unwrapped correctly, then an abrupt phase change can show a speaker resonance.  Listen to Toole's video I posted about how that affects speaker sound quality.
« Last Edit: 31 Mar 2021, 11:21 am by HAL »

wushuliu

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Isn't this the part where someone jumps in and says something about constant directivity and waveguides?

77SunsetStrip

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If the phase of the measurement has been unwrapped correctly, then an abrupt phase change can show a speaker resonance.  Listen to Toole's video I posted about how that affects speaker sound quality.

The phase was not unwrapped, so 2006 vintage speaker phase plot does not have abrupt changes.  Found a good instructional video on REW.  Plan to re-measure both speakers.  Have watched that Toole video several times.  It is interesting and informative.

DaveC113

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Isn't this the part where someone jumps in and says something about constant directivity and waveguides?

They generally provide a greater proportion of direct vs reflected sound, as does listening more in the nearfield.

This helps the listener by clearly conveying fine detail, as long as the rest of the system is capable and if it's a horn/wg, it doesn't mangle the info.

If the listner is presented with spatial info from the recording that dominates the room's effect, this is the point where the room is much less of a factor vs the system and for this thread, where the xo is going to make much more difference vs the room.

The reason the xo is so important is it can smooth over or truncate the spatial information in the recording. The better the xo parts and design, the more clearly you can hear this information, which also makes the room's contribution less important because you have more of the recording's info.

Psychoacoustically, the listener must key in on the recording rather than the room. Once this is accomplished you can certainly still work on the room and perfecting the acoustics even more, but I firmly believe at this point the system is more important than the room... So as I said before the room is ONLY the most important part of the system in the fairly rare case you have extremely problematic acoustics that distracts the listener and prevents the formation of an immersive, 3-D soundstage. In most average rooms you can do some basic things like controlling decay, placement for smoothing frequencies below the transition frequency, maybe treating 1st reflection points if required, and you'll probably get to that point IF you have a good system.

So IMO, this emphasis on the room is misguiding less experienced folks who may have an adequate room and the best bang for the buck is NOT going to be investing in more room treatments! They should be investing in stuff like better xo's instead. In fact, many go way too far and add TOO MANY room treatments, which dulls the sound. There is room for preference in RT60 times as well, some really like a more reverberant field and feels it sound more "live".

DaveC113

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I agree, our brains are wonderfully adept at filtering out a good portion of room acoustics.  So we can still hear good sound in an average room.  But, having had both good rooms and bad rooms myself, it's so much less fatiguing to listen to a great system in a good room.  I think it's because when we're in an average (or bad) room, or brains have to work extra hard at trying to filter out the effects of the room.

When you improve your room, you are literally giving your brain a break.

Yes, with some things it comes down to reducing your brain's necessity for "processing" what it's hearing. But with room acoustics you also get a transition between a "you are there" vs a "they are here" listening experience. My #1 goal is having my system produce the former and avoiding the latter!

HAL

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Since my experience in many show rooms and demo rooms and the only ones that are the you are there were acoustically treated rooms, I still stand by my it is 90% the room and acoustic treatment.

The best sounding stereo setup I have ever heard was in a demo room fully treated with ASC tube traps.  It had a pair of Celestion SL6i minimonitors on stands.  You were at the recording venue for a classical recording.  Only other rooms close were also acoustically treated correctly. 

With todays room acoustic treatments and room measurements capabilities, you can make an excellent sounding room from not so good ones without it.  And it does not have to be loaded with treatments to do it.  absorb the first side wall reflection points and rear wall reflections and it gets much better. 

I laugh when I go to audio shows and see either bare rooms or ferns as the venue for the system.  Usually sounds terrible. 

DaveC113

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Since my experience in many show rooms and demo rooms and the only ones that are the you are there were acoustically treated rooms, I still stand by my it is 90% the room and acoustic treatment.

The best sounding stereo setup I have ever heard was in a demo room fully treated with ASC tube traps.  It had a pair of Celestion SL6i minimonitors on stands.  You were at the recording venue for a classical recording.  Only other rooms close were also acoustically treated correctly. 

With todays room acoustic treatments and room measurements capabilities, you can make an excellent sounding room from not so good ones without it.  And it does not have to be loaded with treatments to do it.  absorb the first side wall reflection points and rear wall reflections and it gets much better. 

I laugh when I go to audio shows and see either bare rooms or ferns as the venue for the system.  Usually sounds terrible.

Demo rooms in audio shows are not a good example of what's possible, or what's best.

I've been to almost every RMAF since RMAF started and have shown my products a couple of years. Much of the issues have to do with poor setup and speaker positioning. Setup has gotten much better over the years but I still wouldn't use audio show systems as a good example as few are ideal. People often travel from far away to setup a system in a room they have never been in, using gear they may have never even tried out before, and are unable to secure adequate room treatments. So audio shows are a special circumstance and expecting proper setup by folks who often are not experts at setup, with no access to acoustic treatments and very limited time to setup with gear they never used is a bit much to ask in many cases.

As you just said yourself, often all it takes a few treatments to "get there". Once you are "there", then the system is far more important than the room. Also, the better the system, the more spatial information from the venue is provided to the listener, which tends to provide that "you are there" experience more readily.

As I said before, my concern is beginners won't recognize if they do or do not have an adequate room. I often see folks go too far in terms of adding acoustic accessories when, IMO, they should probably be working on getting their system to provide better resolution instead, and it's often from reading all over the place that the room is the most important thing. IMO, it may be the most important thing, but it also may NOT be the most important thing. The correct answer is, imo, the room is the most important thing only if it's getting in the way.

Tyson

Dropping amazing equipment into a poor room is going to bottleneck the system.  And conversely, putting a crap system into a great room is not going to sound great either. 

I see so many audiophiles spend big $$ on their speakers/amps/DAC/etc and then put that in an untreated living room or other common area and it just makes me sad.  Even a little bit of treatment will help it enormously. 

DaveC113

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Dropping amazing equipment into a poor room is going to bottleneck the system.  And conversely, putting a crap system into a great room is not going to sound great either. 

I see so many audiophiles spend big $$ on their speakers/amps/DAC/etc and then put that in an untreated living room or other common area and it just makes me sad.  Even a little bit of treatment will help it enormously.

Yeah, but OTOH I guess it's better than nothing and hopefully in the future they will be able to improve setup. Shared spaces are usually going to be limited... 

I think very often the speakers chosen for average living rooms are as much of an issue as the room. Wide dispersion dynamic driver systems are often a poor choice vs other types of speakers in these situations.

Early B.

Yeah, but OTOH I guess it's better than nothing and hopefully in the future they will be able to improve setup. Shared spaces are usually going to be limited... 

I think very often the speakers chosen for average living rooms are as much of an issue as the room. Wide dispersion dynamic driver systems are often a poor choice vs other types of speakers in these situations.

I have a simple approach -- buy whatever speakers you want and don't worry about how they will interact with the room.

Sure, if you have a man cave, you can do whatever you want. But most of us have shared spaces and lots of limitations.

Here's an example of disregarding the room -- most people know that you need plenty of space for open baffle speakers. My first OB sub was placed a few inches against the side wall, and at the time, that was the only place I could put it in a shared space. Nevertheless, it sounded far better than any box sub I ever heard.

Every speaker on the planet can sound better under better conditions.

Your system will never be perfect. There's always trade-offs, so ignore the elephant in the room and enjoy the party anyway.
   


Tyson

And if I'm honest, part of me is upset at my own situation.  I bowed to my wife's wishes for 23 years and then she left.  So screw WAF and all that stupid bullshit. 

The ironic thing is that my living room nowadays looks much nicer than back when I was married.  It's done up in 1950's mid-mod, Mad Men style.  And the acoustic treatments on the walls are wood framed with a walnut stain and a white linen interior, it visually matches the Klipsch Forte IIIs that I have in my upstairs system.  I built these treatment panels so I had unlimited ability to make them work with my space.  It was pretty easy and they look great. 

Early B.

And if I'm honest, part of me is upset at my own situation.  I bowed to my wife's wishes for 23 years and then she left.  So screw WAF and all that stupid bullshit. 

 :lol:

I'm learning this lesson after nearly 30 years of marriage. I just bought some not-so-WAF friendly speakers for the den (shared space). Sometimes you gotta make executive decisions.

Barryg443

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And if I'm honest, part of me is upset at my own situation.  I bowed to my wife's wishes for 23 years and then she left.  So screw WAF and all that stupid bullshit. 


The easiest way to deal with this, trade the wife for a pair of GR-Research NxTremes and a pair of triple subs!

 :P

Barry

Tyson

:lol:

I'm learning this lesson after nearly 30 years of marriage. I just bought some not-so-WAF friendly speakers for the den (shared space). Sometimes you gotta make executive decisions.

Those new speakers of yours are pretty phenomenal :thumb:

DaveC113

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I have a simple approach -- buy whatever speakers you want and don't worry about how they will interact with the room.

Sure, if you have a man cave, you can do whatever you want. But most of us have shared spaces and lots of limitations.

Here's an example of disregarding the room -- most people know that you need plenty of space for open baffle speakers. My first OB sub was placed a few inches against the side wall, and at the time, that was the only place I could put it in a shared space. Nevertheless, it sounded far better than any box sub I ever heard.

Every speaker on the planet can sound better under better conditions.

Your system will never be perfect. There's always trade-offs, so ignore the elephant in the room and enjoy the party anyway.

Also, while your bolded statement is true, IMO you're going farther down the road of diminishing returns once you've achieved that "you are there" presentation. Once your brain is fooled into believing it's in the recording space instead of your living room the room is no longer causing big problems. Small ones, maybe, so I do agree you can still make small improvements all the time.
   

Speakers are such a personal choice and there's no wrong answers, so I can't disagree!

OTOH, if you don't care so much exactly what kind of speaker you get and just want a certain result, then choosing a speaker that has the best chance of working with the room you're putting them in will most likely end up with a more favorable result.

Subs and OB have different rules vs full range speakers since they operate below the transition frequency of the room. You can't say your placement was incorrect without more info.