Speaker room interaction

[Parkandbike]

I'm fighting what I suspect is a room cancellation effect around 125Hz. The solution is probably sitting nearer the speakers, but it is not possible in my listening room. Having spoken to GIK, it was suggested I move the speakers around a bit to try to generate some reinforcement in the frequency range I'm having problems with (using the Antimode if necessary to trim off any unwanted peaks).

I recall seeing a web site which allows you to input room dimensions and then shows expected frequency response as the speakers and listening position are changed. I wanted to play around with this to get some idea of what might work before lugging the Duos around, but I can't find it. IIRC correctly it was on the site of a US dealer and was therefore restricted to the speakers he sells, but it would be a good starting point. Can anyone remember the site (I tried a search)? Any suggestions (regarding the site) greatly received.

 

[Purite Audio]

Could it be this, the room node section is also useful.

http://www.hunecke.de/en/calculators/loudspeakers.html

Keith.

 

[Parkandbike]

Thanks Keith. I think that's it. Memory playing up re nationality!

Could it be this, the room node section is also useful.http://www.hunecke.de/en/calculators/loudspeakers.html

Keith.

 

[Purite Audio]

Measuring your room ( acoustically ) would probably be extremely revealing,

Keith.

 

[Parkandbike]

That's what prompted this!

Do you have any problems with the Hunecke site? I can run it sometimes, but my security settings sometimes block it (no idea why its only sometimes)

Measuring your room ( acoustically ) would probably be extremely revealing,Keith.

 

[Purite Audio]

No the site always opens, it is quite useful, but I really think you need some measuring gear ,something like the XTZ analyser in your room.

Keith.

 

[Parkandbike]

Sorry I did not make it clear. I am using an XTZ analyser. Over the week-end I ran a series of measurements with the mic starting close to the speaker and then moving back towards the listening position. I can't do too much about the listening position so I may have to play around with speaker positioning.

The reason I wanted to play with the Hunecke model is that the Duos are a bit big and heavy to move around, so I wanted to get a feel for what might work before I started the heavy lifting. The model suggests that I should be fairly OK, but in practice I'm getting a bigish dip at 125Hz and another smaller one at about 40Hz. I think the 40hz dip is reflection off the back wall as it moves up in frequency as the mic moves back from the speaker toward the listening chair. The drop at/above 125hz is the main concern though as it makes it difficult to integrate the subs with the horns

It is interesting how sensitive the result as to speaker make and model and unfortunately one can't select AG.

No the site always opens, it is quite useful, but I really think you need some measuring gear ,something like the XTZ analyser in your room.Keith.

 

[Purite Audio]

P&B right I understand, you still get both dips ,whichever distance you position the mic away from the speakers?

I have a big bass suck because of the construction of my room, the speakers can cancel their own bass ,that would change as you moved the speakers or you could be sitting in a null.

Keith.

 

[Alvolake]

Wasn´t the programme called Carmen or something like that ?

 

[Parkandbike]

you still get both dips ,whichever distance you position the mic away from the speakers?.

No.

The problem above 125Hz gets worse as the mic moves away from the speakers, but in practice I can't find a way of sitting any nearer.

The dip around 40hz become more prominent (and moves up from a lower frequency) as the mic approaches the rear wall, so it may be a cancellation from that

I have a big bass suck because of the construction of my room, the speakers can cancel their own bass ,that would change as you moved the speakers or you could be sitting in a null.

Keith.

Yes, since the listening position is approximately in the mid line of the room (but only approximately as the room varies in width) I wondered whether I might be at a null. Given the room is only about 2.2-2.3m high it could also be a null from ceiling/floor interaction. It could also be a longitudinal null, but not the main one. I've tried the obvious calculations, but it's not immediately obvious to me what is going on, so I need to experiment further.

Fortunately it still sounds good subjectively (at least to me), so I'm not too bothered, just looking for ways to improve it.

 

[Purite Audio]

Have you tried entering your rooms dimensions into the room node calculator?

Keith.

 

[Parkandbike]

Thanks. Unfortunately that does not ring any bells for me. There are a number of applications that will calculate room modes or suggest speaker placement, but the link Keith provided is great because it is so visual

Wasn´t the programme called Carmen or something like that ?

- - - Updated - - -

Keith.

Yes. There's also a nice standing wave calculator here if you have not already seen it. http://www.marktaw.com/recording/Acoustics/RoomModeStandingWaveCalcu.html

Thanks again

Don

Have you tried entering your rooms dimensions into the room node calculator?Keith.

 

[Space is the Place]

I tried the room node calculator in room i'm trying to treat at the moment and it proved to very accurate when the dimensions where fed in, its given me a very good idea of what i can hear subjectively and what to do correct it to some extent, especially with lessening the nulls in the bass when listening, so thanks Keith for providing the link.