Author Topic: Narrowband basstraps  (Read 318 times)

Offline seanjammy

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Narrowband basstraps
« on: October 30, 2017, 08:46:55 PM »
My room has a resonance at about 85Hz. I would like to try and smooth this out, but bearing in mind it is quite a narrow spike, I'm reluctant to use  a broadband absorber.

Does anybody know of a tuned bass trap available locally?


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Offline windshear

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Re: Narrowband basstraps
« Reply #1 on: October 30, 2017, 09:48:04 PM »
How do you know its at 85Hz? Have you measured it, or is it just a room rattle?

Offline seanjammy

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Re: Narrowband basstraps
« Reply #2 on: October 30, 2017, 10:01:46 PM »
How do you know its at 85Hz? Have you measured it, or is it just a room rattle?

Itís actually 87Hz. Iím quite sure.

Offline windshear

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Re: Narrowband basstraps
« Reply #3 on: October 30, 2017, 10:39:50 PM »
Itís actually 87Hz. Iím quite sure.

What makes you so sure?

Offline Agaton Sax

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Re: Narrowband basstraps
« Reply #4 on: October 31, 2017, 06:45:21 AM »
For a specific problem like that a few Helmholz resonators are probably optimum.  I have a few of these from Vicoustic

https://www.vicoustic.com/product/vari-bass

I am not sure if they are still locally distributed but I know Simeon Gold at Lee Gold Music ,East London, bought a warehouse full of Vicoustic stuff from the former distributor. I am sure he still has some available

The best combination bass trap I have ever encountered are built by a comany in Port Elizabeth.http://www.acousticpanels.co.za It is quite a complex and heavy ! construction that  uses (so I understand) all three modes of bass control( Helmholz,limp membrane and mass).  I have 2 of their basstraps.Maximum effect is at 80Hz. They are enormously effective and literally suck a very problematic room corner dry.




Untitled by jdza, on Flickr
« Last Edit: October 31, 2017, 06:48:50 AM by Agaton Sax »

Offline seanjammy

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Re: Narrowband basstraps
« Reply #5 on: October 31, 2017, 07:59:48 AM »
For a specific problem like that a few Helmholz resonators are probably optimum.  I have a few of these from Vicoustic

https://www.vicoustic.com/product/vari-bass

I am not sure if they are still locally distributed but I know Simeon Gold at Lee Gold Music ,East London, bought a warehouse full of Vicoustic stuff from the former distributor. I am sure he still has some available

The best combination bass trap I have ever encountered are built by a comany in Port Elizabeth.http://www.acousticpanels.co.za It is quite a complex and heavy ! construction that  uses (so I understand) all three modes of bass control( Helmholz,limp membrane and mass).  I have 2 of their basstraps.Maximum effect is at 80Hz. They are enormously effective and literally suck a very problematic room corner dry.




Untitled by jdza, on Flickr

Thank you very much. Exactly what I need. Will make calls today.

Offline windshear

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Re: Narrowband basstraps
« Reply #6 on: October 31, 2017, 01:04:47 PM »
I'm going to ask again how you say you know its 87Hz. This frequency does not exist on its own in isolation, especially when it comes to room modes.

Offline seanjammy

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Re: Narrowband basstraps
« Reply #7 on: October 31, 2017, 03:20:41 PM »
I'm going to ask again how you say you know its 87Hz. This frequency does not exist on its own in isolation, especially when it comes to room modes.
Thanks for asking. I measured with a 1/3 octave RTA, and then double checked with digital filters. It is a very sharp 87Hz node. There are constructive and destructive points alternating throughout the length of the room, so it can be controlled by moving seating position (but not speakers).

The room is pretty odd (almost no parallel surfaces), and perhaps behaves in an atypical manner.

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Offline seanjammy

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Re: Narrowband basstraps
« Reply #8 on: November 14, 2017, 05:59:04 PM »
For a specific problem like that a few Helmholz resonators are probably optimum.  I have a few of these from Vicoustic

https://www.vicoustic.com/product/vari-bass

I am not sure if they are still locally distributed but I know Simeon Gold at Lee Gold Music ,East London, bought a warehouse full of Vicoustic stuff from the former distributor. I am sure he still has some available

The best combination bass trap I have ever encountered are built by a comany in Port Elizabeth.http://www.acousticpanels.co.za It is quite a complex and heavy ! construction that  uses (so I understand) all three modes of bass control( Helmholz,limp membrane and mass).  I have 2 of their basstraps.Maximum effect is at 80Hz. They are enormously effective and literally suck a very problematic room corner dry.




Untitled by jdza, on Flickr

Unfortunately he was out of stock of the Vari Bass, but ordered a whole lot of other Vicoustic stuff from Simeon. Good guy, tahnks again for the lead.