Behind the AT screen

[Roberto1975]

I am looking for advice please, having read quite a few forums on speakers for behind AT screens and baffle wall construction I am still not sure on the best way to go. Last year I started a dedicated cinema room in the loft. At the time I was using Apex A40 for LCR. Whilst they sounded quite good I thought they were missing something that I used to get from my B&W 603 floor standers, and have recently tried them behind the screen as well. I have also got a rel S2 behind the screen as well as another rel at the back of the room. I have mini DSP them and used my Arcam avr550 and ran Dirac. It all sounds ok, but I know it could be a lot better. Before I start chucking money on new speakers, subs etc, I am sure I can do more with treatments behind the screen and in the room. I can go back to Apex if the will be better for behind the screen as well. I have about 60cms behind the screen and gave a load of acoustic rock wool in the garage to use if I just knew how to do it properly. Any suggestions would be appreciated, I don’t mind refining the behind screen area completely.

 

[Lesmor]

I am looking for advice please, having read quite a few forums on speakers for behind AT screens and baffle wall construction I am still not sure on the best way to go. Last year I started a dedicated cinema room in the loft. At the time I was using Apex A40 for LCR. Whilst they sounded quite good I thought they were missing something that I used to get from my B&W 603 floor standers, and have recently tried them behind the screen as well. I have also got a rel S2 behind the screen as well as another rel at the back of the room. I have mini DSP them and used my Arcam avr550 and ran Dirac. It all sounds ok, but I know it could be a lot better. Before I start chucking money on new speakers, subs etc, I am sure I can do more with treatments behind the screen and in the room. I can go back to Apex if the will be better for behind the screen as well. I have about 60cms behind the screen and gave a load of acoustic rock wool in the garage to use if I just knew how to do it properly. Any suggestions would be appreciated, I don’t mind refining the behind screen area completely.

I am also looking at putting my centre speaker behind my AT screen so will be following your thread

IMO there is a difference between putting speakers behind a screen like you have done and putting them into a proper baffle wall
behind a screen you will still get SBIR cancellations
built into a proper baffle wall will eliminate SBIR and you gain +6db of bass

 

[Roberto1975]

Yes, I am getting to the same conclusion. What I have is essentially just a large void behind the screen, and currently there is only minimal absorption treatment. It sounds reasonable to be fair. I am thinking of putting 75mm acoustic rockwool all the way around the inside area (I’ll cover with black fabric) to try and reduce the reflections, but I think I might be better going back to my apex A40 as I have a feeling that they are better designed for this purpose. My B&W have a front and rear port. I am also considering pulling the sub out and putting it in the corner of the room as I still have a null, despite using the mini dsp and Dirac. All good fun and at least I have options.

 

[Lesmor]

Yes, I am getting to the same conclusion. What I have is essentially just a large void behind the screen, and currently there is only minimal absorption treatment. It sounds reasonable to be fair. I am thinking of putting 75mm acoustic rockwool all the way around the inside area (I’ll cover with black fabric) to try and reduce the reflections, but I think I might be better going back to my apex A40 as I have a feeling that they are better designed for this purpose. My B&W have a front and rear port. I am also considering pulling the sub out and putting it in the corner of the room as I still have a null, despite using the mini dsp and Dirac. All good fun and at least I have options.

You are in a great position to experiment without loosing anymore room length

 

[Triggaaar]

I am also looking at putting my centre speaker behind my AT screen so will be following your thread

IMO there is a difference between putting speakers behind a screen like you have done and putting them into a proper baffle wall
behind a screen you will still get SBIR cancellations
built into a proper baffle wall will eliminate SBIR and you gain +6db of bass

You can also eliminate the SBIR by filling with insulation. This can be useful if you want to toe your speakers in a lot.

For the op:
How much acoustic treatment does your room have (thickness and area)? I'd think treatment (including behind the screen) and an extra sub (if you only have 1) will help add what's missing.

 

[Roberto1975]

No treatment really, other than thin foam tiles behind the speakers and foam bass traps. It definitely needs some absorbttion treatment at first reflection points, and it does get boomy right at the back of my room, not so much at my seAting position though. If all needs a bit of a rethink if honest. I pulled the speakers back out and to the side of screen this weekend and it stArted to sound a lot better even before rerunning Dirac. I do have another small rel sub at the back of the room but I am thinking of getting another sub, possibly an Arendal S1. I would just like to see how good i can get this room sounding without upgrading equipment first, as I think a lot of the issues are down to the room and my lack of knowledge. I have a umic calibration mic , a mini dap HD, REW and the arcam AVR 550 to run Dirac, but just starting to work out what to do. If there was anyone in my area that was clued up I’d happily pay to get this sorted to be honest.
Thanks for your help

 

[Triggaaar]

If there was anyone in my area that was clued up I’d happily pay to get this sorted to be honest.

Where are you based?

I'd forget about changing speakers for a minute, until you've got an idea of what acoustic treatment you can add. It's the most important thing.

If you're building for 1 seat only, you can do well with just one sub, but if you're building for more viewers, an extra sub really helps balance the bass across different seating positions. But you still need treatment too.

 

[Roberto1975]

Up in the north east. Stockton on Tees area. Yeah I thought as much about changing speakers. I’m going to run a few tests with REW when I get the chance and check a few things out. They sound a fair bit better out from behind the screen. I don’t think they are really the type of speaker to go behind a screen really. I’ve got plenty of space to build baffle wall if necessary and I’ve got loads of rock wool the proper acoustic stuff as well, left over from an insulation job. It’s the block stuff so could probably make my own panels.

 

[Triggaaar]

I imagine they'll be fine behind the screen, just use insulation to stop SBIR. It doesn't matter if they lose bass boost, because you'll have subs anyway.

 

[John Woodcock]

try placing the sub in the middle. I had a single 18 in the middle of the room before i went for two 12s at a 1/4 of the way in.

 

[Smurfin]

Suggestion:

Definitely fill with rockwool, but also go and buy 3 of these and get rid of the B&Ws and forget about the Apex:

Behringer B215XL Eurolive

Full Range Loudspeaker Rated power: 250/ 1000 W (RMS/ peak), 15" Woofer and 1.75" tweeter, Sensitivity: 96 db, Impedance: 8 Ohm, Frequency range: 55 - 20,000 Hz, Dispersion: 70° x 40°, Input: jack/ speaker twist, 35 mm Mount, Dimensions approx. 695...

www.thomann.de

Horn based designs are perfect for discrete builds where you don't see the speakers.

 

[Roberto1975]

try placing the sub in the middle. I had a single 18 in the middle of the room before i went for two 12s at a 1/4 of the way in.

I’ve just added another Rel. Picked up a R-528 SE very reasonably. Same drivers as the Gibraltar. Sound great for music and with the S2 now at the back of the room LFE sounds amazing. I’ll still have a play around with location though.

 

[Roberto1975]

I’ve been making some some absorbing panels out of the rock wool acoustic 75mm and covered them with MELV2 and put them at the first reverb points and to be honest it’s starting to sound really good, especially the new Sub. I added a lumagen to the system from Gordon from convergent AV. HE calibrated my X7500 when here and it’s looking unbelievable now. I’m just trying to get the audio to live up to the visual

 

[stevie0]

Up in the north east. Stockton on Tees area. Yeah I thought as much about changing speakers. I’m going to run a few tests with REW when I get the chance and check a few things out. They sound a fair bit better out from behind the screen. I don’t think they are really the type of speaker to go behind a screen really. I’ve got plenty of space to build baffle wall if necessary and I’ve got loads of rock wool the proper acoustic stuff as well, left over from an insulation job. It’s the block stuff so could probably make my own panels.

How much is loads ?

Any for sale ?

 

[Roberto1975]

How much is loads ?

Any for sale ?

I’ve got about 12 packets of the RWA45 I thought it was the 75mm but I it could be the 100mm I’d have to check when back home. I as going to use it for another project to be honest. By the time I’m done in this room I might get through it anyway