Changing variables in a review

ddk

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As I recall the reviewer made no mention of such possibilities. Didn't the reviewer state that the amp caused the bass to improve hence, that is what caused him to reposition his speakers? If so, that seems extremely odd if not downright corny. For several reasons.
I listed some possibilities that might solicit speaker relocation nothing to do with any specific reviewer. I only recall the reviewer suggesting speaker position as a possible reason for the different final outcomes.
1. I've been rather fastedious about speaker placement since 2002 and with tremendous success IMO. Like many others, I've purchased or audtioned lots of gear and with many sonic improvements under my belt, well over 500 just in my current system. In all those events I can think of but 2 situations that ever caused me to even consider moving my speakers and that's when I'm switching rooms or in the early stages of fine-tuning my subwoofers and even then, rarely. No other situations have. And I've never heard of any others claiming to have inklings such as this reviewer. Now perhaps this reviewer's a bit deeper than me and this is a next step in progress that I'm unaware of, but I doubt it. To the contrary, when I do encounter a component that improves the bass or anything else, the only thing I'm looking for is more music.
We have a different take from what the reviewer actually said.
2. In my dabbling with speaker placement in the attempts to achieve a superior bass, I've concluded that to achieve a superior bass,
there must be some type of accoustic coupling that occurs between a speaker and the room.
Difficulty in this type of discussion starts with not knowing one another, going solely by your videos and your subwoofer setup I can say with certainty that my definition of superior bass and yours aren't the same. I've talked about coupling & decoupling terminology used in regards to audio equipment don't make a lot of sense for me. I see no physical way to "couple" a speaker to the room, spiking it down to the floor is simply that and you can do it in less than ideal location too.
It's beyond my pay grade to prove an actual accoustic coupling occurs but it makes sense to me. One thing I do know as part of this so-called acoustic coupling is that there exists an acoustic noise-floor such that when a speaker is moved a fraction in any direction either more or less bass is audible and the audible bass is more or less defined. The fact that I have to physically move the speakers to cause this change should be proof that there's some type of acoustic coupling that occurs, right? Now any new component can also cause bass to change but that's electrical only and should have nothing whatsoever to do with a speaker's geography. IOW, at least in this reviewer's case I can't see any direct correlation between the electrical improvement causing one to alter the mechanical / acoustic side.
I don't see the interaction between the room and sound waves as a coupling of any kind, speaker position is fluid many variables are involved including speaker type and design.

Not always but a change of amplification can definitely force a speaker location change if for nothing else than tonal balance. I can easily demonstrate it with some of my speakers with two tube amps using same output tubes only difference is topology.
Ummmmm, sure. But in the middle of a review? The more I think about it, the more one word comes to mind. Misguided. Moreover, I suspect if he had any real savvy and knowing that many are unaware of such a practice, I'd guess that if he has such a brainfart, he'd be wise to keep it to himself. Better yet, if he's into performing due diligence, then swap back in the old amplifer at some point so that his referencing stands a better chance of being stable and then cover it all in his review.
Never mentioned anything about start, middle or end of a review process or a review for that matter only listed what could cause a position change.

How many products including your own rack go through iterations, sorry brainfarts but are fine yet repositioning a speaker is misguided :)? In regards to speaker location what does reinserting the other amp if there's one to begin with prove that's so essential?

david
 

Robh3606

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I don't see the interaction between the room and sound waves as a coupling of any kind, speaker position is fluid many variables are involved including speaker type and design.


Hello David

I am little surprised you are saying that. The speakers most defiantly couple to the room. Proof of that is the excitation of the primary and secondary room modes that cause the +10 and -10 db or more peaks and suck outs. Not to mention all the rattles and shakes from individual objects or windows and your turntable if you are careless in set-up.

In order for you "couple" and excite these modes you need an energy/excitation force and the speakers output is what provides it.

Now I am not sure we are using the same definitions as far as coupling but in my mind they certainly do.

Not always but a change of amplification can definitely force a speaker location change if for nothing else than tonal balance. I can easily demonstrate it with some of my speakers with two tube amps using same output tubes only difference is topology.

That's all about the impedance curves the speaker present as a load on the amps. I can understand a change for sure from the interaction and how it affects the frequency response. Must say though I have never experienced one too make me change speaker positions. You have a lot more gear experience than I do. I can certainly understand why that would be so with tube designs. Can't see that with solid state amps.

Rob :)
 

ddk

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Hello David

I am little surprised you are saying that. The speakers most defiantly couple to the room. Proof of that is the excitation of the primary and secondary room modes that cause the +10 and -10 db or more peaks and suck outs. Not to mention all the rattles and shakes from individual objects or windows and your turntable if you are careless in set-up.

In order for you "couple" and excite these modes you need an energy/excitation force and the speakers output is what provides it.

Now I am not sure we are using the same definitions as far as coupling but in my mind they certainly do.
Hi Rob,
We're probably not thinking of coupling in the same way, what you mentioned above is room and speaker interaction and affects of sound waves on the structure all this and more can happen no matter where you place the place the speakers in the room and IMO irrelevant to speaker setup vis-å-vis sound quality. Reason I said everything is fluid is because, volume both as in sound levels and room dimensions along with placement and frequencies and construction can produce all types of effects. Also your "best" location vis-å-vis sound quality is still dependent on listener position. In your definition would say that the listener is room coupled too?
That's all about the impedance curves the speaker present as a load on the amps. I can understand a change for sure from the interaction and how it affects the frequency response. Must say though I have never experienced one too make me change speaker positions. You have a lot more gear experience than I do. I can certainly understand why that would be so with tube designs. Can't see that with solid state amps.

Rob :)
It very much can be speaker's impedance curve. the speaker has a 16 ohm impedance while one of the amps has an 8 ohm tap. With that amp upper mids and high frequencies become annoying and nasal. Bass is also altered and lightish now but moving the speakers closer to one another by 1.5" on each side and an 1" closer to the front wall restores tonal balance and bass quantity I get from the amp with 16 ohm tap an 1" forward and 3" more apart. Again I don't see room coupling by any stretch coming into play here.

david
 
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ddk

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A question for @stehno & @Robh3606 or anyone else who thinks of room/speaker interaction in terms of coupling and decoupling, do you consider applying diffusion to your front wall as some type of decoupling of the speakers and using absorption a better coupling to the room? What about a combination of both?

It's not a trick question I'm just curious of how everyone's using this terminology. I believe @stehno includes some physical form of attaching the speakers to the structure as part of this room/speaker coupling, is this where the distinction lies?

david
 
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morricab

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A question for @stehno & @Robh3606 or anyone else who thinks of room/speaker interaction in terms of coupling and decoupling, do you consider applying diffusion to your front wall as some type of decoupling of the speakers and using absorption a better coupling to the room? What about a combination of both?

It's not a trick question I'm just curious of how everyone's using this terminology. I believe @stehno includes some physical form of attaching the speakers to the structure as part of this room/speaker coupling, is this where the distinction lies?

david
I think this applies mostly in the bass...particularly for a speaker like a corner horn that actually uses the room to extend the horn...that is most definitely coupled to the room.
 
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ddk

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I think this applies mostly in the bass...particularly for a speaker like a corner horn that actually uses the room to extend the horn...that is most definitely coupled to the room.
Yes some corner horns benefit/need a physical connection to the walls but not all and this doesn't answer the question regarding all other speakers. What about the listener and listening position with the corner speaker is that considered some type of coupling too? What if I have to add a corner and it's not attached to the structure in the same way as the other corner am I still coupled to the room? Again not a trick question, just trying to gather data.

david
 
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stehno

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A question for @stehno & @Robh3606 or anyone else who thinks of room/speaker interaction in terms of coupling and decoupling, do you consider applying diffusion to your front wall as some type of decoupling of the speakers and using absorption a better coupling to the room?
You literalist, you. :) When I use the term acoustic coupling between a speaker and its room, it's just a term I made up to imply a type of superior interface or synergy between the two. It was not intended to be interpreted as a coupling taken in the same sense as mechanical coupling / decoupling.

But then again, maybe there is. I dunno. But there is something mechanical/acoustical in nature that occurs since when a speaker's geographic position is changed within a given room, bass will most always improve or degrade, as will bass defintion. This implies to me that there exists some type of an acoustic or mechanically-induced noise floor (as opposed to a playback system's electrical-induced noise floor) depending entirely on a speaker's mechanical / acoustical interaction with its room.

Personally, I think the phrase acoustic coupling works well enough for my use anyway. If that suffices for me, that was not intended to necessarily imply there must an acoustic decoupling as well. But then again for all I know maybe there is. Regardless, it's just a phrase I made up to somehow describe a tight or superior coupling, interface, and/or synergy mechanically / acoustically between a speaker and its rooom.

What about a combination of both?
Not to go down this rabbit hole, but in the world of vibration mgmt, there is no pure isolation (decoupling) method employed and there is no pure resonance energy transfer (coupling) method as both are simply impossible to achieve. Hence, we're all employing hybrids whichever method we lean toward. So if one were to take the same mindset and terms toward a room's acoustics, well, that too is mechanical in nature, right?

It's not a trick question I'm just curious of how everyone's using this terminology. I believe @stehno includes some physical form of attaching the speakers to the structure as part of this room/speaker coupling, is this where the distinction lies?

david
Actually I don't. Components, racking system, and subwoofers, yes. But speaker, no. Since the designer of my speakers did not believe in the coupling methodology I've no choice at the present and I've yet to bring something to fruition. But I have designed it and anxious to implement.

Anyway, hope that clears up some confusion there.
 
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K3RMIT

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I thought school was out for the holidays. Better pay attention to david he is one who does know
we all can learn from him and I thank him for taking the time to help us
 

Mike Lavigne

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A question for @stehno & @Robh3606 or anyone else who thinks of room/speaker interaction in terms of coupling and decoupling, do you consider applying diffusion to your front wall as some type of decoupling of the speakers and using absorption a better coupling to the room? What about a combination of both?

It's not a trick question I'm just curious of how everyone's using this terminology. I believe @stehno includes some physical form of attaching the speakers to the structure as part of this room/speaker coupling, is this where the distinction lies?

david
coupling and decoupling a speaker and room, in my mind relates more to volume of air moved, and the size and degree of sealing of the room. you want the low frequencies to be able to 'hook up' and allow the bass and musical energy to be physical. typically this does not involve surface diffusion. more mass and large trapping implements....and then matching the room with the energy of the speaker.

OTOH; i do have a speaker<->wall interaction in my room, which "could" be termed coupling/decoupling that is influenced by diffusion. my bass towers are massive; 7 foot tall, 750 pounds, and 35 inches long. they are near the side wall on each side. as i was tuning my room and experimenting 5 years ago now, i discovered that there was a distortion coming from that interaction of musical energy reflecting back and forth between the wall and side cabinet. i experimented with various solutions, and came upon adding three Aural T-Fusor diffusors on the wall opposite each bass tower. my room naturally retains a lot of musical energy, and i do tend to push things.

problem solved.

you might also note the cloth next to the T-Fusors; that cloth tames the side reflection from the opposite passive tower, since the bass towers block the near speaker<-> wall reflections.

1640643880122.png
 
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Robh3606

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A question for @stehno & @Robh3606 or anyone else who thinks of room/speaker interaction in terms of coupling and decoupling, do you consider applying diffusion to your front wall as some type of decoupling of the speakers and using absorption a better coupling to the room? What about a combination of both?

It's not a trick question I'm just curious of how everyone's using this terminology. I believe @stehno includes some physical form of attaching the speakers to the structure as part of this room/speaker coupling, is this where the distinction lies?

david


Hello David

I look at 2 types of coupling one being physical and the other acoustic. From my experience the physical coupling is much less significant. I see that as vibrations from the cabinet being coupled through say a floor. I have footers on my cabinets to help mitigate that.

It's the acoustic coupling that I see as the real issue. I see diffusers and bass traps as devices that help scatter reflections and absorb energy to help disrupt the coupling. If you are using tuned bass traps obviously you want to absorb the energy and remove or dampen the bass peaks of the primary room modes.

I use a couple of crude bass traps in my room that are essentially just stacks of absorber in the two corners with listening chair between.

Hi Rob,
We're probably not thinking of coupling in the same way, what you mentioned above is room and speaker interaction and affects of sound waves on the structure all this and more can happen no matter where you place the place the speakers in the room and IMO irrelevant to speaker setup vis-å-vis sound quality. Reason I said everything is fluid is because, volume both as in sound levels and room dimensions along with placement and frequencies and construction can produce all types of effects. Also your "best" location vis-å-vis sound quality is still dependent on listener position. In your definition would say that the listener is room coupled too?


Ok but I hope you realize that improper speaker placement can excite the room modes. Ideally you want the speaker and listening positions to be out of these worst case positions in the room. These positions are defined by the wavelength and the physical size of the room. There are several on line calculators you can use to see where these points would be located. Problem is they are for rectangular rooms only and don't take into account openings and such so their utility is a bit limited. Fun to play with!

I don't see me as coupled unless I start singing along at which point the Hi Fi part of the experience is shall we say ruined!


Rob :)
 
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ddk

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I thought school was out for the holidays. Better pay attention to david he is one who does know
we all can learn from him and I thank him for taking the time to help us
:D

coupling and decoupling a speaker and room, in my mind relates more to volume of air moved, and the size and degree of sealing of the room. you want the low frequencies to be able to 'hook up' and allow the bass and musical energy to be physical. typically this does not involve surface diffusion. more mass and large trapping implements....and then matching the room with the energy of the speaker.

OTOH; i do have a speaker<->wall interaction in my room, which "could" be termed coupling/decoupling that is influenced by diffusion. my bass towers are massive; 7 foot tall, 750 pounds, and 35 inches long. they are near the side wall on each side. as i was tuning my room and experimenting 5 years ago now, i discovered that there was a distortion coming from that interaction of musical energy reflecting back and forth between the wall and side cabinet. i experimented with various solutions, and came upon adding three Aural T-Fusor diffusors on the wall opposite each bass tower. my room naturally retains a lot of musical energy, and i do tend to push things.

problem solved.

you might also note the cloth next to the T-Fusors; that cloth tames the side reflection from the opposite passive tower, since the bass towers block the near speaker<-> wall reflections.

View attachment 87087

Sorry Mike I'm unclear if you would use the term coupling with the room when discussing speaker placement?

Is bass frequency hookup is this where you'd think of a room/speaker coupling? What if when the low frequencies travel through the walls to other spaces, same effect but no containment?

david
 

ddk

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Hello David

I look at 2 types of coupling one being physical and the other acoustic. From my experience the physical coupling is much less significant. I see that as vibrations from the cabinet being coupled through say a floor. I have footers on my cabinets to help mitigate that.

It's the acoustic coupling that I see as the real issue. I see diffusers and bass traps as devices that help scatter reflections and absorb energy to help disrupt the coupling. If you are using tuned bass traps obviously you want to absorb the energy and remove or dampen the bass peaks of the primary room modes.

I use a couple of crude bass traps in my room that are essentially just stacks of absorber in the two corners with listening chair between.




Ok but I hope you realize that improper speaker placement can excite the room modes. Ideally you want the speaker and listening positions to be out of these worst case positions in the room. These positions are defined by the wavelength and the physical size of the room. There are several on line calculators you can use to see where these points would be located. Problem is they are for rectangular rooms only and don't take into account openings and such so their utility is a bit limited. Fun to play with!

I don't see me as coupled unless I start singing along at which point the Hi Fi part of the experience is shall we say ruined!


Rob :)
I don't disagree with your assumptions Rob but I'm mainly trying to understand how people relate to coupling when talking about speaker positioning. Is the best location where you don't excite the room which can be interpreted as decoupled or when you excite the room which one can say it's coupled. Bass frequencies travels through layers walls, floors and ceilings of every type where's what's the speaker coupled to 5 apartments over? I understand pressure, wavelength, resonance and room nodes but don't see any coupling acoustical or mechanical and if that happens how does it mean good sound?

david
 

Mike Lavigne

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Sorry Mike I'm unclear if you would use the term coupling with the room when discussing speaker placement?

Is bass frequency hookup is this where you'd think of a room/speaker coupling? What if when the low frequencies travel through the walls to other spaces, same effect but no containment?

david
sorry; i'm dropping into the middle of your conversation so maybe my post is not relevant to your point.

and yes; as my post mentions, 'coupling' to me in terms of speaker/room is mostly degrees of speaker energy/room size/build matching. i use the term 'hook up' to describe what i'm looking for.

sure; speaker placement can affect coupling. as height off the floor, proximity to walls, the structural make-up of walls, all contribute to speaker/room coupling. and a few other things likely too.

as far as traveling through walls; you have to consider what it takes to establish room boundaries to focus the bass. in my case; 6 years after i built my room, i added a layer of Quietrock 545, plus a layer of 3/4" finish grade plywood on the front half of my room to attain a good leverage for effective bass hookup. i think it works well. the bass is physical and the room is lively.
 
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Robh3606

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I don't disagree with your assumptions Rob but I'm mainly trying to understand how people relate to coupling when talking about speaker positioning. Is the best location where you don't excite the room which can be interpreted as decoupled or when you excite the room which one can say it's coupled. Bass frequencies travels through layers walls, floors and ceilings of every type where's what's the speaker coupled to 5 apartments over? I understand pressure, wavelength, resonance and room nodes but don't see any coupling acoustical or mechanical and if that happens how does it mean good sound?

david

Yes the best location would be where you excite the lowest number of room modes for speaker postilions and a listening position that is not where/minimum again a room modes occurs. The bottom line is ideally you would want a room with no resonances but of course this cannot be so.

To bad Duke is not part of this. He uses his SWARM to smooth the overall room response and the actual speaker positioning and polarity helps smooth the overall room response.

https://www.audiokinesis.com/the-swarm-subwoofer-system-1.html

Bass does indeed travel and how rigid the walls are will determine the Q of the resonance. Concrete in a basement High Q sheetrock lower Q

Rob :)
 
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morricab

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Yes some corner horns benefit/need a physical connection to the walls but not all and this doesn't answer the question regarding all other speakers. What about the listener and listening position with the corner speaker is that considered some type of coupling too? What if I have to add a corner and it's not attached to the structure in the same way as the other corner am I still coupled to the room? Again not a trick question, just trying to gather data.

david
Other speakers also couple to a room when close to a wall or a corner...it’s commonly called room gain, can be several dB and again primarily impacts the Bass. Not quite sure why you are so hung up on semantics because everyone knows we are not talking about literal hard physical coupling...like train cars. We are also not talking about room modes as those are both additive and subtractive in nature. Therefore the listener is not “coupled” to the room.
 

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In this Stereophile review of the First Watt SIT3 by Herb Reichert, the amplifier was not working with Herb's 16 ohm Zu's or the 15 ohm Falcon speakers. On the instructions of Nelson Pass, the reviewer used a resistor to shunt down the impedance of the speakers so the amp could match. I see this as an acceptable variable change for this review. Some might not.

 

morricab

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In this Stereophile review of the First Watt SIT3 by Herb Reichert, the amplifier was not working with Herb's 16 ohm Zu's or the 15 ohm Falcon speakers. On the instructions of Nelson Pass, the reviewer used a resistor to shunt down the impedance of the speakers so the amp could match. I see this as an acceptable variable change for this review. Some might not.

Not something the average audiophile will be comfortable doing but also not a review “foul”
 
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Lagonda

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sorry; i'm dropping into the middle of your conversation so maybe my post is not relevant to your point.

and yes; as my post mentions, 'coupling' to me in terms of speaker/room is mostly degrees of speaker energy/room size/build matching. i use the term 'hook up' to describe what i'm looking for.

sure; speaker placement can affect coupling. as height off the floor, proximity to walls, the structural make-up of walls, all contribute to speaker/room coupling. and a few other things likely too.

as far as traveling through walls; you have to consider what it takes to establish room boundaries to focus the bass. in my case; 6 years after i built my room, i added a layer of Quietrock 545, plus a layer of 3/4" finish grade plywood on the front half of my room to attain a good leverage for effective bass hookup. i think it works well. the bass is physical and the room is lively.
That is why i like brick rooms for bass response.
 
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ddk

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Other speakers also couple to a room when close to a wall or a corner...it’s commonly called room gain, can be several dB and again primarily impacts the Bass. Not quite sure why you are so hung up on semantics because everyone knows we are not talking about literal hard physical coupling...like train cars. We are also not talking about room modes as those are both additive and subtractive in nature. Therefore the listener is not “coupled” to the room.
I'm looking at starting a thread focused on a room with very acoustics and speaker placement then going through an actual project modifying the character of the room with basic construction materials, I don't want to get bogged down on terminology mid thread, coupling doesn't work for me so I want to know what others mean when they use it in this context.

david
 
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