Soundstage

Nebulator

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Mar 16, 2019
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We moved to a new place and I'm struggling with speaker placement, soundstage issues and lack of bass (I hear bass elsewhere in the room just not where I sit) and I can't get it right no matter where I place the speakers or where I sit.

For speaker placement and soundstage I usually listen to Roger Waters Amused to Death. This album mimics surround from 2 speakers when/if speaker placement is good. Effects are really precise and accurate when right. In my new place I can't get it right (its mostly trapped between the speakers and they are not out of phase). And like I mentioned, bass is often lacking too unless its really obvious and prominent.

Is it possible with REW (I own a UMIK) to measure how good a soundstage is (or what is wrong with it) with a particular speaker placement? And if it can, would it also become obvious what kind of change is needed? For example, if a certain measurement is off in a particular way, it means the speakers need to be closer to each other or something?

In addition, would you say that for certain my issues will be fixed with the right acoustic panels?

Thanks for the help!
 

John Mulcahy

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Apr 3, 2017
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If the room is rectangular you can use REW's room simulator to get a rough idea of how the bass response will look at different speaker and listening positions. Soundstage is not something that can be readily measured. Lack of symmetry can be problematic, as can reflections from surfaces near the speakers or listening position, but a lack of sidewall reflection can also be a factor - reflections from the sidewalls can be beneficial for the soundstage sometimes.
 

Nebulator

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Thank you. I think the room is too complex, it consists of multiple rectangles differing in size and there are large windows with curtains too.

Maybe someone can help me out here. I've attached 2 measurements. Can you point me to any issues you can identify in those measurements?

Main issue is that from listening position there is no bass to be heard. When I stand elsewhere in the room I hear it just fine. Is this obvious from those measurements?

I'd be happy to make new ones if I need to make them with other settings.

Thanks in advance!
 

Attachments

John Mulcahy

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Apr 3, 2017
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There are several strong resonances at the low end, and quite a gap in the left channel from 50 to 60 Hz, so the low end is very uneven. Higher up the range the region from 200 to 600 Hz is a bit low compared to 600 Hz to 2 kHz, which may also contribute to the bass light impression.

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One thing you can try is to play the Pink Periodic Noise test signal and look at the response on the RTA with the settings below as you move the mic to different listening positions or move the speakers to different positions with the mic in the listening position and look for places with a more even response.

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jtalden

Senior Member
Joined
May 22, 2017
Messages
316
Location
Arizona, USA
My AV System  
Preamp, Processor or Receiver
Marantz AV7705 Pre/Pro
Main Amp
Rotel RMB-1066 6 chnl P-amp x 2
Additional Amp
Behringer DCX2496 x 2
Universal / Blu-ray / CD Player
OPPO BDP-103 Universal Player
Front Speakers
DIY SEAS H1456/H1212 Spkr x 5
Subwoofers
DIY JBL 2235H 15" SW x 2
Video Display Device
JVC DLA-X790R
Screen
Da-Lite Da-Snap 39105V - 92"
Maybe someone can help me out here. I've attached 2 measurements. Can you point me to any issues you can identify in those measurements?

Main issue is that from listening position there is no bass to be heard. When I stand elsewhere in the room I hear it just fine. Is this obvious from those measurements?
The left channel measurement is negative polarity. the right channel measurement is positive polarity. This issue may be due to the sound system wiring. In some cases, the measurements appear this way when the sound system is wired correctly and instead there is an incorrect cable connections in the measurement setup. If it is in the sound system that may be a significant part of the lack of bass.
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Nebulator

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Thread Starter
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Mar 16, 2019
Messages
16
The left channel measurement is negative polarity. the right channel measurement is positive polarity. This issue may be due to the sound system wiring. In some cases, the measurements appear this way when the sound system is wired correctly and instead there is an incorrect cable connections in the measurement setup. If it is in the sound system that may be a significant part of the lack of bass.
In my new place I can't get it (sound stage) right (its mostly trapped between the speakers and they are not out of phase).
THANK YOU THANK YOU THANK YOU!!
You'll probably glad you're not around otherwise I would have kissed you.

You have no idea how stressed out I've been over this. This is a load off my shoulders. When we moved to this new place, much bigger than our old place I expected the Magnepans to sound so much better. I just couldn't get it right! I've been so disappointed and stressed out. I checked polarity several times but because the cables are not marked I have to follow it from amp to speaker to check. I must have messed it up. How the hell did I miss that!? And after that I dismissed the possibility that the speakers could be out of phase.

I will make new measurements next weekend, I expect those to look a little different ;).

Thanks again!! Everything sounds mostly right now. The bass is back, soundstage is good. It's not perfect there are still room acoustics to fix but finally! ... :greengrin:

/Happy Nebulator signing off to spin some records :p.
 

jtalden

Senior Member
Joined
May 22, 2017
Messages
316
Location
Arizona, USA
My AV System  
Preamp, Processor or Receiver
Marantz AV7705 Pre/Pro
Main Amp
Rotel RMB-1066 6 chnl P-amp x 2
Additional Amp
Behringer DCX2496 x 2
Universal / Blu-ray / CD Player
OPPO BDP-103 Universal Player
Front Speakers
DIY SEAS H1456/H1212 Spkr x 5
Subwoofers
DIY JBL 2235H 15" SW x 2
Video Display Device
JVC DLA-X790R
Screen
Da-Lite Da-Snap 39105V - 92"

Nebulator

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Thread Starter
Joined
Mar 16, 2019
Messages
16
So ... I was just thinking about that graph and which speaker was actually out of phase. The left channel measurement was negative polarity and the right channel measurement was positive polarity.

But in reality the left was connected correctly, and the right channel was out of phase.

Does that actually matter? As long as speakers are connected the same all is good right? Magnepans are dipoles, does that make a difference?
 

jtalden

Senior Member
Joined
May 22, 2017
Messages
316
Location
Arizona, USA
My AV System  
Preamp, Processor or Receiver
Marantz AV7705 Pre/Pro
Main Amp
Rotel RMB-1066 6 chnl P-amp x 2
Additional Amp
Behringer DCX2496 x 2
Universal / Blu-ray / CD Player
OPPO BDP-103 Universal Player
Front Speakers
DIY SEAS H1456/H1212 Spkr x 5
Subwoofers
DIY JBL 2235H 15" SW x 2
Video Display Device
JVC DLA-X790R
Screen
Da-Lite Da-Snap 39105V - 92"
The common convention is the highest frequencies are normally taken as the reference and the polarity set to provide positive going sound pressure first. I don't know if that is always the choice for manufactures however. The type of speaker is not a factor in the choice as it is a physical characteristic of the sound pressure. Your right speaker was set positive polarity. The left was set negative assuming your measuring setup does not invert the signal. That is unlikely, but does happen.

I think it is very unlikely that many listeners would be able to identify a sound quality difference in double blind testing. Just choose either one or try both settings and chose the one you like better.
 
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