Polk SDA-2A vs Infinity RS IIIb

Gardenstater

Bass is pretty omnidirectional so I think what you are experiencing are null points from standing waves and the geometry of your room. Bass traps would be a good idea. Tube Traps are good choices for taking care of bass issues.

pitdogg2

Sounds like you may be sitting in a null area.
It seems to me these speakers and your room do not get along. It may be time to decide whether or not you either get rid of them or live with the deficiencies of the room and speakers interaction.

Bleiz

I know about null areas (as a soundengineer in studios since 1987) and I don't think that is the problem here as I've tried both standing and sitting-listening at many different positions and the same thing occurs, the bass is fuller when I stand up anywhere in the room and at the same time off axis from the bass drivers.

It is about the physics, tilted forwards or not the bass gets weaker when sitting down, never experienced anything like it before, therefore I conclude that these were made for standing listening where they excel, have gotten the same response from other RSIIIb Infinity members here in Sweden so I'm not alone in this experience.

Bleiz

To continue on my previous post and as replies to the null suggestions I can agree to this as well, tried standing on a chair and the bass resonance of the room got louder, of course, so there's the interaction and however you tune and tweak you never get it perfect but I can live with it, it is not a control room where you build and treat perfect for the mixing position, it is the living room and one must accept any deficiency but try to get the best overall resonance, the direction/projection is good just about anywhere in the room so far.
Just to show how I placed a big thick 2 x 3 meter carpet in front of the speakers, maybe to move it backwards a bit etc, at the same time the dimensions floor to ceiling 236 cm's is the ghost here I suppose thus moving speakers back and forth won't change too much?!

Bleiz

Did draw them yet a couple of inches back into the room and the overall tuning now seems to be much better and the "sweetspot" (marked w. x)

isn't necessary exactly within the equitriangle but that's fine as this is the living room meant for enjoying the music not overanalyzing like down in the studio ;-)
In the studioworld there is this LEDE application since many years; "live end-dead end", might do a half-tweak LEDE this room as well just for fun if so I'll dampen the wall behind the speakers***

jdjohn

I've been watching this thread with interest since I have a pair of RS IIIa myself, albeit in storage at the moment. When I got them, they did supplant a pair of SDA-2B.

The general consensus with these speakers is that they are not bass-heavy, but rather, have a tighter, more-controlled, bass response. A person might think that with two 10" bass woofers, the bass response would be greater (and wider), but I wonder if part of the 'problem' is the usage of phase plugs in the woofers. Those tend to focus the direction (I think), which could explain the smaller 'sweet spot'...at least for bass response from those woofers. Compare this with Infinity Kappa series speakers, which have the more typical woofer dust cap. I can't say first-hand if Kappas have more bass response, but maybe someone else can comment.

What I can comment on directly is that my RS 5 (mini-me) speakers, with two 6" woofers (sporting dust caps), have a surprising amount of bass response

Bleiz

jdjohn wrote: »

I've been watching this thread with interest since I have a pair of RS IIIa myself, albeit in storage at the moment. When I got them, they did supplant a pair of SDA-2B.

The general consensus with these speakers is that they are not bass-heavy, but rather, have a tighter, more-controlled, bass response. A person might think that with two 10" bass woofers, the bass response would be greater (and wider), but I wonder if part of the 'problem' is the usage of phase plugs in the woofers. Those tend to focus the direction (I think), which could explain the smaller 'sweet spot'...at least for bass response from those woofers. Compare this with Infinity Kappa series speakers, which have the more typical woofer dust cap. I can't say first-hand if Kappas have more bass response, but maybe someone else can comment.

What I can comment on directly is that my RS 5 (mini-me) speakers, with two 6" woofers (sporting dust caps), have a surprising amount of bass response

I thank you for this comment and am very well aware that theese Infinity's are made for neutral but tight response that's why I bought them to begin with, I don't like disco Cerwin Vega bottom pump don't get me wrong here I know why I like the Infinity's plain and simple...the thing is I'll keep them even if it means I have to be standing up for sweetspot-listening, they sound great in any other place in my room so far so good :-)

Bleiz

To repeat the issue with these towers, they sound just perfect for my taste but you have to be standing in sweetspot to get the full natural pleasure, for otherwise music enjoying escapades they sound great wherever you are in the room***

jdjohn

Does closing that pocket door on the left help at all? Also wondering if pulling the rug up would give you more bass reflection instead of the rug potentially absorbing some of that energy. Then again, removing the rug might make the room a little too lively.

audioluvr

jdjohn wrote: »

Does closing that pocket door on the left help at all? Also wondering if pulling the rug up would give you more bass reflection instead of the rug potentially absorbing some of that energy. Then again, removing the rug might make the room a little too lively.

I think this is the problem. When you stand up your ears are receiving more bass reflections off the ceiling and less off the floor (which the rug is absorbing. Either remove the rug or move your listening position closer to the speakers.

Gardenstater

One thing about rugs and carpet is that they really don't absorb much in the low frequency range. Just not thick enough by a long shot.

jdjohn

Gardenstater wrote: »

One thing about rugs and carpet is that they really don't absorb much in the low frequency range. Just not thick enough by a long shot.

I wondered about this, but could experiment anyway as a learning exercise. Those low frequency waves are so looong and strong, I can understand. This is why we hear bass from neighbors and passing cars, but not as much treble. I still wonder about that open pocket door in OP's room.

Bleiz

The pocket door as you say is in my world not the issue, standing up or sitting down makes a big difference and I continue to state this is due to the physics of these towers***

Gardenstater

Bleiz wrote: »

The pocket door as you say is in my world not the issue, standing up or sitting down makes a big difference and I continue to state this is due to the physics of these towers***

The only thing I can think of would be lobing in the vertical direction due to interference of the waves from the two woofers interacting; constructively and destructively. Seems a bit odd at those long wavelengths however, for it to be that noticeable, not to mention the fact that the drivers are very large and pretty far away from a point source.

Can you play some low Hz tones and test with a dB meter and verify what you are hearing?

dromunds

I’ve had both the RSIIIa as well as Kappa 8. The Kappas had superior bass (and were a superior speaker) but the RS were no slouch in the bass department that’s for sure. The RSIIIa’s were really good speakers. Good clean power will bring out their best, and lesser quality power will result in lesser quality sound including bass. Rooms can also result in less than optimum sound quality, including bass.

xschop

You could double-check the woofer terminal connections are correct. Just one woofer out of phase will rob the bass output.

Gardenstater

Looks like both of those woofers play the same signal and they play all the way up to 600Hz. I can't tell really if those "phase plugs" are attached to the cone or if they are attached to the pole piece and fixed.

Phase plugs have more of an effect upon high frequencies. Very little to no effect upon low ones.

Gardenstater

Attached to the cone it is as visible in this vid at 1:11

https://www.youtube.com/watch?v=MxzV3hp2o3w

Bleiz

and???

halo71

Gardenstater wrote: »

I can't tell really if those "phase plugs" are attached to the cone or if they are attached to the pole piece and fixed.

Phase plugs have more of an effect upon high frequencies. Very little to no effect upon low ones.

On my RSIIIa's, they are attached to the cone.

xschop

Agree with George. If they move with the cone, they are not phase plugs.

audioluvr

Gardenstater wrote: »

One thing about rugs and carpet is that they really don't absorb much in the low frequency range. Just not thick enough by a long shot.

That would be correct if the rug was vertical and directly between the speaker and the listener but they are not.

bcwsrt

Bleiz wrote: »

The pocket door as you say is in my world not the issue, standing up or sitting down makes a big difference and I continue to state this is due to the physics of these towers***

I have a similar setup in my basement with a pair of vintage Polk RTA-15TLs where the right speaker is basically in a corner and the left one is open to the rest of the basement. Admittedly, not anywhere near the same type of speaker really, other than both being "towers," but ... I've run YouTube test tones with the dB/frequency analyzer app I have on my iPhone (not perfect by any means, but it gives me a general idea) and there is a substantial difference between left and right dB and frequency response.

In my case, GIK room treatments and dual subwoofers have helped to tame standing waves and force the bass frequencies out into the room to where the the sound is consistent throughout the listening area. In fact, I have substantially different settings on my left subwoofer than the right just to get something anywhere close to the same response from the left and right channels to achieve the consistency I have. So, IMO, your room placement with that open area to the left (and possibly combined with the "hole" the other room is creating), along with all the hard surfaces you have there are not helping your issue.

I understand that you are educated in sound engineering, but if you are discounting your room-related problems as being non-issues versus the design of your speakers, you are not thinking big picture.

Bleiz

bcwsrt wrote: »

Bleiz wrote: »

The pocket door as you say is in my world not the issue, standing up or sitting down makes a big difference and I continue to state this is due to the physics of these towers***

I have a similar setup in my basement with a pair of vintage Polk RTA-15TLs where the right speaker is basically in a corner and the left one is open to the rest of the basement. Admittedly, not anywhere near the same type of speaker really, other than both being "towers," but ... I've run YouTube test tones with the dB/frequency analyzer app I have on my iPhone (not perfect by any means, but it gives me a general idea) and there is a substantial difference between left and right dB and frequency response.

In my case, GIK room treatments and dual subwoofers have helped to tame standing waves and force the bass frequencies out into the room to where the the sound is consistent throughout the listening area. In fact, I have substantially different settings on my left subwoofer than the right just to get something anywhere close to the same response from the left and right channels to achieve the consistency I have. So, IMO, your room placement with that open area to the left (and possibly combined with the "hole" the other room is creating), along with all the hard surfaces you have there are not helping your issue.

I understand that you are educated in sound engineering, but if you are discounting your room-related problems as being non-issues versus the design of your speakers, you are not thinking big picture.

I get the picture, just wouldn't like to admit this up until now as I didn't have those issues with the bookshelves B&W's before and in the same room.
Will start with some absorbers on the walls + ceiling to begin with, at the spots where you can see the speakers while a friend holds a mirror to the surface and moves it along.

nooshinjohn

I don’t think that tv is helping matters. The shape of that thing would not be audio friendly IMHO

Gardenstater

When I watched this recent video (around 8:30) of the B&W 802 Matrix from Danny Richie it reminded me of your bass suckout situation. He shot the woofers separately from the tweeter and mid and you can see that when he measured at tweeter level there was a large bass suckout due to the time arrival difference, albeit well above the crossover frequency. Could be a similar situation going on in your speakers, I don't know, but this shows what I was talking about with destructive interference.



https://www.youtube.com/watch?v=wmmw8QlThPk&t=6s