# Fix for muddy sound at higher volume levels?



## Guest (Nov 23, 2008)

I finally got a decent set of speakers to replace some hand-me-down Bose cubes (I know... but they were free). The new speakers (Jamo C807s) put out a lot more sound pressure however, and while dialog and lower volume effects sound MUCH tighter, once the SPL ramps up things are starting to get murky especially in the lower frequencies. I don't have a dedicated room (this is also my family room) and I was hoping for some suggestions I can try without going overboard on panels and traps.

I've got an 18x18x12 room in an old building. The walls and ceiling are about an inch and a half of plaster over lath. The right side wall is 8' high windows with moderatly thick fabric drapes and the floor's hardwood. I've got a 10' x 12' x 1/2 inch thick wool throw rug under the couch that should cover the floor reflection point for the fronts.

The primary viewing position is a couch 11' from the front wall and 7' from the back wall. The fronts are 3' out from the front wall and 4' on either side of the screen. They're toed in towards the center of the couch with the tweaters at ear level. The center is about 2' from the front wall, directly under the TV (65" DLP), and angled up slightly. The surrounds are about a foot behind the couch above ear level on the side walls (right is mounted between two of the windows). The sub is a Velodyne CHT-100 and is currently directly to the right of the screen 1' out from the front wall and 7' from the right side wall. This is just about the best I can do with the speaker placement and keep the room functional for anything other than watching movies =)

I've got a budget south of $1000 and I can get away with a few panels here and there, but I'm not going to be able to cover over the windows or anything crazy. What I'm really wondering here, is whether it's worth my time to try and treat the current room given these parameters, or whether I should just live with it a few years until I can dedicate a room to home theater.

I just ordered a couple of Gik's 244 traps to play around with since they seem to be about the best absorption value for the price. Any recommendations on placement... I was thinking rear corners of the room... maybe try the first reflection points on the left wall and ceiling instead though? Sigh, I've caught the bug haven't I?

Thanks,
Perk

Gear list:
Toshiba 65" 1080p/24hz DLP TV
Toshiba HD-A35 HDDVD player
Sony 40gb PS3
Motorola HDDVR (thanks Charter!)
Onkyo TX-SR605
Jamo C 807 Fronts biamped
Jamo C80 Center
Jamo C80 Surrounds
Velodyne CHT-100 Sub


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## thewire (Jun 28, 2007)

Nobody has chimed in yet so I will see if I can help. If I am moving into a new HT, my treatments are going with me. They also do not get old (most of them) or need much maintenance. A nice thing to consider when treating a room you might not be in years from now. I might try the 244's slightly behind the seating on the side walls. This may be part of the problem with the back of the room, but of course those panels are excellent for testing areas to deal with such as the back wall, first reflection points like when hitting a bank shot in pool, or holding the mirror half way between the speaker and seat. If you are just playing with them I would just try every location and try watching some material you are familiar with. The corners are a great start to look into. REW would be a great tool for treating the room.


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## atledreier (Mar 2, 2007)

Could it be the amp that start to complain at high levels?


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## Doctor X (Apr 3, 2007)

I think improving the acoustics will help with the muddy sound you are experiencing at higher levels but at the same time I don't think the 605 has nearly enough juice to power the C807's properly. I would imagine the 805 or 876 as a minimum. 

After you've added absorption to the room you'll need even more power on tap.

I know this is going off-topic but I own the C803's and I'm thinking of upgrading to the 807's. Could you please send me some pictures of your 807's with and without grills via PM. I've got my speakers hooked up to the Onkyo 876. Sorry for going off-topic.

Regards,


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## bpape (Sep 14, 2006)

Hi Perk

Welcome to the Shack. 

Try the 244's in a couple of different places to see what each one does for you. If you could make a few more posts so you could put up a couple of pics, that would help. My first try would be the front corners - just set them on the floor leaning against the wall and straddling the front corners if you can.

In a living room environment, the Pillars work very well and can be 'decorated' with sculptures, flowers, etc. on top of them to make them blend better. They're excellent performers for the floorspace taken up. 

Bryan


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## Guest (Nov 23, 2008)

Thanks guys. I'll get some pictures when I get home both of the room and of the 807s for you Vaughn.

As for the 605 - it's rated at 90 watts per channel into 8 ohms... the Jamos are 6 ohm though and rated to 180 watts so it's entirely possible I'm not driving them enough. I do have the front channels bi-amped though (the 605 lets me use the rear surround channels as additional front channels), specifically to reduce the number of magnets that 90 watts has to move. As I understand it, the 6" woofer is isolated to the bottom pair of binding posts, and the 6" midrange and tweeter are isolated to the top pair.

Is there any empirical way to test whether I'm maxing out the amp constantly? It doesn't seem to be getting any hotter than it used to. Multimeter across the binding posts under load? Divide AC voltage squared by 6 ohms, or would that work under dynamic load? Probably wouldn't be anything close to accurate but might be close enough to see if I'm running over 90 watts for extended periods...

Bryan, thanks for the suggestions... I'll definatly try the 244s in various different places and see how things sound. I have a sneaking suspision I'm going to have to get one of those radioshack SLMs and play around with REW too though. I also just ordered a copy of the Master Handbook of Acoustics... nothing like a new hobby =)


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## Doctor X (Apr 3, 2007)

Thanks Perk. Speaking of acoustic treatment, I've already placed an order for 4 GIK tri-traps and 3 244 traps. I can't get them just yet as I'm sorting out other things at the moment but I can't wait to hear the difference.

So I look forward to hearing your impressions on the 244 traps once everything is set up. I also look forward to seeing the 807 pics. Thanks.

Regards,


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## tonyvdb (Sep 5, 2007)

You mention that your room is 18x18' with a 12 foot ceiling, that's a really bad room for acoustics as its a perfect box and will give you all sots of cancellation issues particularly on the lower end. 
Yes the Onkyo is 90watts per ch but that's only half the problem. The Jamo speakers will have a difficult time filling the space given its almost 4000 cubic feet of space. 
Obviously you cant move walls to correct the dimensions but you can as others have mentioned add some traps and some acoustic panels.
What do you have the crossover set at in the Onkyo?


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## Doctor X (Apr 3, 2007)

Perk, did you ever get a chance to set everything up ? Just thought I would ask as it's been a couple of days. Thanks.

Regards,


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