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As a long time sufferer of poor room modes in the bass region and no space to install passive bass traps this has me very interested!!

 

anyone have any experience or know of other cheaper alternatives?

 

https://www.soundseasy.com.au/collections/bass-traps/products/psi-audio-avaa-c20-active-velocity-acoustic-absorberm

 

 

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I don't see a particularly good reason why it has to be active.  Variable yes, but active??? Your room modes are not changing and generally you are dealing with one of them.  I guess because active sounds better than passive ? 

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Posted (edited)

I think it's active because it's creating air pressure maybe like a phase reversal cancellation effect 

 

If it does what it says on the box and is no bigger then a sub would be a good solution bit at 3K you could have the room custom tuned??????

Edited by mpearce38

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3 hours ago, mpearce38 said:

anyone...know of other cheaper alternatives?

 

Room correction: Dirac/DEQX etc.

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Yes that is a good option 

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Many years ago,in another life, we experimented  with a passive notch filter  in the 60 hz range, seemed to work on a 50,000$ genesis speaker quite well ,and other hi end speakers we tried it on,just had to get the filter,in the right range, with I think a 24 dB slope cost a couple of hundred $  or in today’s money 5 toilet rolls

 

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Yes interesting as Pro audio use EQ to tune live rooms

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These certainly sound interesting if they do what the marketing spiel says.  But I didn't find any notes on best practice for using them.  Is it just 1 or 2 placed anywhere in the room, or is it closer to one behind each speaker to absorb the rear waves and create more of a front focussed cardiod radiation from the speakers?

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On 21/03/2020 at 1:31 AM, mpearce38 said:

As a long time sufferer of poor room modes in the bass region and no space to install passive bass traps this has me very interested!!

 

anyone have any experience or know of other cheaper alternatives?

 

https://www.soundseasy.com.au/collections/bass-traps/products/psi-audio-avaa-c20-active-velocity-acoustic-absorberm

 

 

There is a good review of these units by the Pro Audio magazine, Sound on Sound.

https://www.soundonsound.com/reviews/psi-audio-avaa-c20

 

The main problem is having just one unit does very little, you need 4 to get a decent effect, and probably 6 to 8 to really sort bass problems out [$24k -$32k ], and then they only effect problems from 150hz down, so you'll still need some sound treatment to sort those out [although doing that is a LOT easier]

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If you're not into diy, then it's far cheaper and gets predictable/better results to use someone that solves these problems for a living, ie an acoustical engineer. 

You can find these in most companies selling both acoustical materials and technical advice.

 

Most of the passive "bass traps" are restricted to freq above 150Hz, so aren't bass traps at all (the actual bass frequencies are below 120Hz) -  no problem with this but when talking about it, this often becomes an area of confusion particularly as pro-audio guys expect people to know about it, but most of us have just a vague idea.  It can get confusing very quickly!

 

Bass traps below 120Hz are not physically small and first, you need to find what is/are the actual problem frequencies and how much absorption is required so, a simple measurement session is the start to give you specific figures to work with. 

 

It's not that expensive and usually comes with suggestions on how to start sorting out the problems involved

 

Also, it's not just the freq response in the bass area (bass & low mids) you need to look at but how long the offending energy stays in your room (decay rates) and this is where the engineer earns his fee and you benefit from his experience.

 

I'm not sure if Paul Spencer is still doing this, but it's worth a phone call (Red Spade Audio)  - Audio Consultants are rather expensive so always get a quote for what specific services are charged for as many just dislike domestic jobs.

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Posted (edited)

I very recently bought a pair of IK Multimedia MTM powered studio monitors [haven't arrived yet]

They have built in DSP and each speaker [they are sold individually] comes with a calibration mic.

 

 

The thing is, you can also buy the full recently updated V3 [April 2nd 2020 ] room calibration software and mic separately.

It's reasonably priced at Euro 99 or Euro 149 with mic.

https://www.ikmultimedia.com/products/index.php?R=INIT&FV=arc-system-family-related-products&CV=Other Filter&PSEL=arc

 

Here is a review of the original software in pro audio magazine Sound on Sound.

https://www.soundonsound.com/reviews/ik-multimedia-arc

And a later review when it got a update to V2 back in Oct 2013.

https://www.soundonsound.com/reviews/ik-multimedia-arc-2

 

If running a PC based playback system you could take some room measurements using your current speakers and the software will show you where your problem frequencies are.

You could put your room dimensions into a MODE calculator like the one linked below.

https://amcoustics.com/tools/amroc?l=304&w=260&h=244&r60=0.6

This will give you the basic of where the most problematic modes will occur [this is for a empty room].

Any furnishings, carpet, curtains in the room will all make a actual difference to those bare basic results, this is where the mic and calibration software gives you a far better idea.

 

Then it's hit the internet and read up on building some room treatments [building them is easy, getting the correct batting for Bass traps, and knowing how wide/deep they need to be to be effective against the problem frequencies in YOUR room is another matter.[ light fluffy batting put in the corners with space behind it so the sound hits the wall corners and reflects back into the batting works the best], BUT you need to know the exact problem frequencies, one size does not fit all.

 

Thankfully this stuff is cheap to do, Selex 2400 x 140 x 12 shiplap lining board make a suitable frame work, it's $10 a length from Bunnings.

https://www.bunnings.com.au/selex-2400-x-140-x-12mm-pine-primed-shiplap-lining-board_p0021273

Midrange and high frequency sound treatments are easy, it's always the Bass that's the hard one to treat.

 

I'd get the software and mic, measure your room, then set about building Bass traps for behind your main speakers, re measure the room, rinse and repeat with further room treatments, then when room pretty well acoustically treated, use DSP to fine tune.

Edited by Tweaky

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