Curbing room boom

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ajayrav

Curbing room boom
« on: 1 Feb 2014, 07:22 pm »
Hello folks,

I have a very small listening room (10X11) and of course room modes are rearing their ugly head muddying the bass.  One wall (left) is a sliding glass door.  I listen near-field, about 6.5 feet from the speakers with the speakers toed-in appropriately.

My room response is shown below



My equipment consists of an Modwright Oppo BDP-105 with Sophia Electric ^sn7 tubes and a Mullard Blackburn rectifier, Bolder modded Squeezebox Touch with Bolder Power Supply, Primaluna Dialogue One tube amp with SED winged 'C' EL34s, ACI Sapphire XL on Sound Anchor stands (Scanspeak revelator sliced paper cone woofer and Scanspeak 9300 Silk dome tweeter), REL T5 subwoofer.  Cables are a mix of Reality Cable, WyWires and Shunyata.

Here are pics of the room

Rear left



Left front



Right front



Right rear



Due to the small size of the room, I an only put bass traps on the wall behind the TV.  I was thinking of 4 244s, maybe 2 with diffusor plates.  Would these make a difference?  I'm trying to avoid equalization...

Any input is appreciated....

Thanks,
Ajay





Big Red Machine

Re: Curbing room boom
« Reply #1 on: 1 Feb 2014, 07:29 pm »
I think that 70 hz bump is the ceiling height.  I had a similar bump and could only associate to the 8 ft height.  You can calculate the wave for 8 ft from the bob gold calc I believe.  The rest of the sweep looks pretty good to me.

Try some couch cushions and pillows at the bounce point out front of the speakers on the floor and remeasure to see if it moves some.

roscoeiii

Re: Curbing room boom
« Reply #2 on: 1 Feb 2014, 08:12 pm »
I know you didn't want to mess with equalization, but with that room and those measurements, I'd look into a DSPeaker Dual Core 2.0. It can help with big humps in particular. Dips can be harder to get rid of with DSP. I love mine. Use it with both my digital and vinyl rigs. DSP for the bass, and then you can manually adjust the EQ elsewhere in order to tweak the sound to your liking. With that glass sliding door, I'd guess you might find you have a little channel imbalance, which the DSPeaker could also adjust.Check out Greene's review in The Absolute Sound.

And Tweek Geek offers these for audition or with a solid return policy. So a risk-free proposition.

That said, I also think that you could also benefit from treatment (though I don't see too much room for it). And how much does WAF need to be taken into account? You're likely stuck with the glass doors, though thicker curtains may help. The plant behind one of your speakers could be replaced by a bass trap. And maybe could something be attached to the closet doors behind your listening position.

If BRM is correct, then looking into treatment for the ceiling could help? Again, WAF will be a concern.

Really not an expert, so just throwing out ideas. Brian Pape at GIK has always been super helpful with my challenging rooms. Hopefully he or someone else from GIK will pipe in soon. But in that room, it may turn out that your options are limited.

JLM

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Re: Curbing room boom
« Reply #3 on: 1 Feb 2014, 09:52 pm »
The apparent closet in the back looks at a Helmhotz resonator tuned to 70 Hz to me.  Otherwise find another non-square room (or try the EQ).

ebag4

Re: Curbing room boom
« Reply #4 on: 1 Feb 2014, 11:42 pm »
My room is 10.5'x12.5', I am running GR Research V1s which use a pair of 12" servo bass units per side in an open baffle alignment.  I have also used a pair of Hawthorne Augie (15") driver in OB as we'll.  Neither of these solutions produced boomy bass in this room.  If possible you might try an OB sub.

Best,
Ed

Glenn Kuras

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Re: Curbing room boom
« Reply #5 on: 4 Feb 2014, 11:36 am »
Quote
Due to the small size of the room, I an only put bass traps on the wall behind the TV.  I was thinking of 4 244s, maybe 2 with diffusor plates.  Would these make a difference?  I'm trying to avoid equalization...

It would be a good start, which we could always add move over time.  It may not flatten the peak you have but it will help with the decay times. See more about decay times here.
http://www.gikacoustics.com/understanding-decay-times/
If you would like for use to dive  a bit more into detail on your room, I recommend using the following form so we can work with you one on one.
http://www.gikacoustics.com/acoustic-advice/

Glenn Kuras
GIK Acoustics
« Last Edit: 4 Feb 2014, 03:21 pm by Glenn Kuras »

MaxCast

Re: Curbing room boom
« Reply #6 on: 4 Feb 2014, 11:55 am »
I'd like to see a measurement without the sub on and speakers set to full range.  Looks like you should be able to do something with xo point and some sub eq.

bpape

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Re: Curbing room boom
« Reply #7 on: 4 Feb 2014, 12:14 pm »
I would agree with Pete and check into the height issue. Closet behind could be a contributing factor.  I would also want to take a look at the waterfall of your room.  I would also play with the xover point. Are you running the Sapphires full range and then bringing the sub in to overlap or are you cutting off the Sapphires? If so, where and using what?

If you need to get down to 70, Monster Traps are your best option. If enough broadband already, I would consider the range limiter membranes on them.  I don't think you have enough space behind you to allow the scatter plates to function correctly. 

Guidof

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Re: Curbing room boom
« Reply #8 on: 4 Feb 2014, 11:52 pm »
I know you didn't want to mess with equalization, but with that room and those measurements, I'd look into a DSPeaker Dual Core 2.0. It can help with big humps in particular. Dips can be harder to get rid of with DSP. I love mine. Use it with both my digital and vinyl rigs. DSP for the bass, and then you can manually adjust the EQ elsewhere in order to tweak the sound to your liking. With that glass sliding door, I'd guess you might find you have a little channel imbalance, which the DSPeaker could also adjust.Check out Greene's review in The Absolute Sound.

And Tweek Geek offers these for audition or with a solid return policy. So a risk-free proposition.

That said, I also think that you could also benefit from treatment (though I don't see too much room for it). And how much does WAF need to be taken into account? You're likely stuck with the glass doors, though thicker curtains may help. The plant behind one of your speakers could be replaced by a bass trap. And maybe could something be attached to the closet doors behind your listening position.

If BRM is correct, then looking into treatment for the ceiling could help? Again, WAF will be a concern.

Really not an expert, so just throwing out ideas. Brian Pape at GIK has always been super helpful with my challenging rooms. Hopefully he or someone else from GIK will pipe in soon. But in that room, it may turn out that your options are limited.

I second these recommendations. I have both GIK tri traps AND a DSPeaker Dual Core, and found both indispensable for taming room modes in a small room with my Martin Logan SL3s and REL T1 sub.

Regards,

Guido F.