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Speakers near the front wall - bass port
Old 30th December 2019
  #1
Speakers near the front wall - bass port

This was likely asked a thousands times. I read here that the speaker should go (at least in smaller rooms) close to the front wall. And as the bass is omnidirectional it should not matter if the speaker is front or rear ported. On the other hand the myth that it's not a good idea to put rear ported speakers close to the wall seems quite common. I read it everywhere and even in manuals. Yamaha e.g. suggests to put the speakers 1-2 feets from the wall IIRC.

Can speakers principally be designed for near wall positioning or are there speakers that work better near a wall?

Do you have a good reference for that topic?
Old 30th December 2019
  #2
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Quote:
Originally Posted by Lilith View Post
This was likely asked a thousands times. I read here that the speaker should go (at least in smaller rooms) close to the front wall. And as the bass is omnidirectional it should not matter if the speaker is front or rear ported. On the other hand the myth that it's not a good idea to put rear ported speakers close to the wall seems quite common. I read it everywhere and even in manuals. Yamaha e.g. suggests to put the speakers 1-2 feets from the wall IIRC.

Can speakers principally be designed for near wall positioning or are there speakers that work better near a wall?

Do you have a good reference for that topic?
With or without port, the speakers should be near the front wall as much as possible.
Old 30th December 2019
  #3
Quote:
Originally Posted by dinococcus View Post
With or without port, the speakers should be near the front wall as much as possible.
Do you have a good source for that or is there any engineer who wrote this? Just wonder why so many people are wrong on that point.
Old 30th December 2019
  #4
Old 30th December 2019
  #5
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Quote:
Originally Posted by Lilith View Post
Do you have a good source for that or is there any engineer who wrote this? Just wonder why so many people are wrong on that point.
Do you have measurements prove your assumptions?
Old 30th December 2019
  #6
I have no assumptions at all ... With wrong I mean putting them not near the wall.
Old 31st December 2019
  #7
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Offering this page again as this comes up often and it seems to be quite helpful.
http://arqen.com/acoustics-101/speak...-interference/

"Generally, a gap of 0 to 8 inches (0 to 20 cm) between your speakers and front wall is a good starting point to minimize coloration caused by SBIR. But, check your loudspeaker specs for a recommended minimum distance.

For example, Genelec recommends a minimum distance of 2 inches (5 cm) to allow for amplifier cooling and rear opening sound radiation."
Old 31st December 2019
  #8
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https://www.bkelec.com/HiFi/Sub_Woof...th-df_Plus.htm

B&k monolith with the port against the floor.
Old 5th January 2020
  #9
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Quote:
Originally Posted by Lilith View Post
Do you have a good source for that or is there any engineer who wrote this? Just wonder why so many people are wrong on that point.
The main issue is SBIR. This might help:
Attached Thumbnails
Speakers near the front wall - bass port-neumann_loudspeaker_boundary_location_v02-sbir-table-wall-bounce-distance.jpg  
Old 5th January 2020
  #10
nms
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nms's Avatar
Quote:
Originally Posted by Lilith View Post
the myth that it's not a good idea to put rear ported speakers close to the wall seems quite common. I read it everywhere and even in manuals.
But do you ever read it suggested by reputable studio designers?

Quote:
Yamaha e.g. suggests to put the speakers 1-2 feets from the wall IIRC.
Yamaha's customer base are primarily people in untreated or poorly treated rooms though, so do keep that in mind. In an untreated room you'll likely find the LF overpowering if placed close to the wall. Genelec on the other hand have covered the effects of front wall SBIR in their literature, warning about the phase cancellation that takes place with speakers pulled away from the wall.

Quote:
Originally Posted by Lilith View Post
Just wonder why so many people are wrong on that point.
People with a good understanding of room acoustics or who have used room measurement programs to test these things and get a better understanding of them are a minority.

If you pull your speakers away from the front wall you will delay the heavy low frequency reflection. Delayed sound mixed with direct sound causes out of phase frequencies. It's simple as that.

A speaker port needs to be unobstructed to perform its job. That's it. If your speakers are rear ported and you place them close to the wall facing straight forward as some may do in their livingrooms, then sure.. that's going to interfere with their operation. Don't do that.

One of the great longstanding errors people make with room acoustics is that there are a lot of things which may be right or wrong ONLY under specific circumstances. And people who don't understand that or the circumstances will incorrectly assume something they saw or heard transfers over to other settings where it does not. The devil is in the details, as they say.

Quote:
Originally Posted by Wayne View Post
"Generally, a gap of 0 to 8 inches (0 to 20 cm) between your speakers and front wall is a good starting point to minimize coloration caused by SBIR. But, check your loudspeaker specs for a recommended minimum distance.

For example, Genelec recommends a minimum distance of 2 inches (5 cm) to allow for amplifier cooling and rear opening sound radiation."
It's best not to post stuff like this as it's missing critical information needed to correctly implement it. It will be right or wrong depending on whether untreated vs treated room, specifics of room treatment, and whether the speakers are angled or not. If the speakers aren't angled then yes 2" from the wall is the minimum Genelec recommends, but that generally isn't applicable for studio use. And certainly there will be a BIG difference between 0 or 8". Some may get the mistaken idea that anywhere in that range should be fine.

Last edited by nms; 5th January 2020 at 11:43 AM..
Old 5th January 2020
  #11
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If Yamaha is the NS10, Yamaha preconize the use in a living room with the speaker in the corner.
Old 6th January 2020
  #12
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Quote:
A speaker port needs to be unobstructed to perform its job. That's it. If your speakers are rear ported and you place them close to the wall facing straight forward as some may do in their livingrooms, then sure.. that's going to interfere with their operation. Don't do that.
Exactly. Or of you do want to do that, then damp the port sufficiently that it's no longer a problem... which might not be a bad idea with some speakers in any case, to cure the artifacts created by the port! (I probably shouldn't have said that, I guess: you are right about that too.... people will see that, then try to damp their ports without truly understanding what that means, or how to do it, or what the consequences will be, or why.... but I wanted to mention that it is a possible solution, for some speakers, under some circumstances, when you understand what's going on and need to use the speaker in a way that it is not normally used....)

- Stuart -
Old 7th January 2020
  #13
Quote:
Originally Posted by nms View Post
But do you ever read it suggested by reputable studio designers?

Yamaha's customer base are primarily people in untreated or poorly treated rooms though, so do keep that in mind. In an untreated room you'll likely find the LF overpowering if placed close to the wall. Genelec on the other hand have covered the effects of front wall SBIR in their literature, warning about the phase cancellation that takes place with speakers pulled away from the wall.

People with a good understanding of room acoustics or who have used room measurement programs to test these things and get a better understanding of them are a minority.

If you pull your speakers away from the front wall you will delay the heavy low frequency reflection. Delayed sound mixed with direct sound causes out of phase frequencies. It's simple as that.

A speaker port needs to be unobstructed to perform its job. That's it. If your speakers are rear ported and you place them close to the wall facing straight forward as some may do in their livingrooms, then sure.. that's going to interfere with their operation. Don't do that.

One of the great longstanding errors people make with room acoustics is that there are a lot of things which may be right or wrong ONLY under specific circumstances. And people who don't understand that or the circumstances will incorrectly assume something they saw or heard transfers over to other settings where it does not. The devil is in the details, as they say.

It's best not to post stuff like this as it's missing critical information needed to correctly implement it. It will be right or wrong depending on whether untreated vs treated room, specifics of room treatment, and whether the speakers are angled or not. If the speakers aren't angled then yes 2" from the wall is the minimum Genelec recommends, but that generally isn't applicable for studio use. And certainly there will be a BIG difference between 0 or 8". Some may get the mistaken idea that anywhere in that range should be fine.
Thanks, that pretty much answered my question.
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