Smoothing FR with "lesser" subs? - AVS Forum
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post #1 of 40 Old 07-14-2014, 04:02 PM - Thread Starter
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Smoothing FR with "lesser" subs?

I have 4 PSA XS15s in my ~5000 cubic foot living room. After many months of pushing subs around my room and measuring with REW I've finally got them setup to where I'm getting the output I needed (craved) but I've got a ~10db null at 60hz at the MLP, and my other two listening positions are kinda outa whack.

I've considered getting 1 or 2 more XS15s but that just ain't in the budget right now. I'm considering buying a pair of "lesser" subs and running them in the back of the room in hopes of smoothing my response and leveling out the seat-to-seat variance.

I have a MiniDSP that I could use to delay the rear subs and employ a HPF to keep the really low stuff out of them.

The subs I'm considering are the Dayton SUB-1200. If you see this post, they sure have a respectable FR (at least in that room).

Is this just crazy or do you think it would be worth a try? Looks like Parts Express would take them back without any issues, but I would have to pay return shipping (which could be pretty hefty, the subs are 45lbs. each).
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post #2 of 40 Old 07-14-2014, 04:30 PM
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If you mean less subs, it's worth a try. I don't see what a lesser sub would bring to the table. Before adding anything, have you thought about turning one of your subs off? It could be that one of the four subs is helping to cancel some of your frequency response. I'd try turning one off and keep switching which one is off until you've gone through all possibilities. Hey, it sure can't hurt to try.
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post #3 of 40 Old 07-14-2014, 04:47 PM
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The sub1200's are going to introduce more distortion and limit the systems overall output. I would place the XS15's for best response and wait until you can upgrade further. Another option is to sell all 4 XS15's and go DIY. You can build a serious system with that money. 4 SI-18's and a Peavy IPR 2 7500
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post #4 of 40 Old 07-14-2014, 05:02 PM
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I have 4 subs and eventually moved the subs from nearfield to far apart. Two of the subs are 20 ft. from the MLP. The room response is more even and flat this way with no loss of tactile sensation. I run all speakers set to small. Also, adding additional subs beyond 4 don't do much for the room response. Where are your subs in the room? Is everything set to small?

Two subs will get the FR 75%, 3 subs 90%, and 4 subs 95% + on the room FR.

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post #5 of 40 Old 07-14-2014, 05:04 PM
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I have a Dayton sub 1500 and I think it's terrific...
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post #6 of 40 Old 07-14-2014, 05:32 PM
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Quote:
Originally Posted by derrickdj1 View Post
I have 4 subs and eventually moved the subs from nearfield to far apart. Two of the subs are 20 ft. from the MLP. The room response is more even and flat this way with no loss of tactile sensation. I run all speakers set to small. Also, adding additional subs beyond 4 don't do much for the room response. Where are your subs in the room? Is everything set to small?
I think you missed the part where Alan said he had the subs placed every way possible over the last several months. Spreading them out (2 up front/ 2 in rear) yields the smoothest response, but leaves some headroom to be desired. Placing all 4 up front yields the most headroom at the expense of a 60hz null. The best solution is to go with 4 more powerful subs and place them where the response was good. That is why I suggested DIY being Alan is budget limited.


On a side note Alan, if you insist on the Dayton route I would go with at least a pair of Sub1500's.

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post #7 of 40 Old 07-14-2014, 05:52 PM
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Quote:
Originally Posted by Alan P View Post
I've considered getting 1 or 2 more XS15s but that just ain't in the budget right now. I'm considering buying a pair of "lesser" subs and running them in the back of the room in hopes of smoothing my response and leveling out the seat-to-seat variance.

(...)

Is this just crazy or do you think it would be worth a try? Looks like Parts Express would take them back without any issues, but I would have to pay return shipping (which could be pretty hefty, the subs are 45lbs. each).
User kgveteran tried a similar thing and devoted a construction thread to it. He did have problems with the auxiliary subs not having enough output, but I don't think it was resolved whether it was due to the driver/box combo or just amplification. The latter is of course an easier problem to solve. I believe he moved out of that residence before reaching a final resolution.
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post #8 of 40 Old 07-14-2014, 08:43 PM - Thread Starter
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Originally Posted by basshead81 View Post
The sub1200's are going to introduce more distortion and limit the systems overall output. I would place the XS15's for best response and wait until you can upgrade further. Another option is to sell all 4 XS15's and go DIY. You can build a serious system with that money. 4 SI-18's and a Peavy IPR 2 7500
Once again BH you make a lot of sense....the only problem is that I don't think I stand a snowball's chance in **** of selling my PSAs locally. I live in a pretty small town (50K people) and I don't know a single person who would even consider a Dayton 1200, let alone quad XS15s.

I really really wish I woulda done more research before my current subs (not that the PSAs don't rock...they do), but what's done is done.

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Originally Posted by basshead81 View Post
I think you missed the part where Alan said he had the subs placed every way possible over the last several months. Spreading them out (2 up front/ 2 in rear) yields the smoothest response, but leaves some headroom to be desired. Placing all 4 up front yields the most headroom at the expense of a 60hz null. The best solution is to go with 4 more powerful subs and place them where the response was good. That is why I suggested DIY being Alan is budget limited.


On a side note Alan, if you insist on the Dayton route I would go with at least a pair of Sub1500's.
I most certainly do not insist on Daytons - was just a crazy idea really. I think if I got 2 more XS15ses I'd be in bass heaven....I'll just have to save my pennies until I can get there! In the meanwhile, the system sounds pretty dang good....in my seat at least.
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post #9 of 40 Old 07-14-2014, 09:02 PM
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I did not know you had the 4 subs up front. BH is correct, to get the output and FR you will need more powerful subs.

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post #10 of 40 Old 07-15-2014, 02:08 AM
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Quote:
Originally Posted by Alan P View Post
Once again BH you make a lot of sense....the only problem is that I don't think I stand a snowball's chance in **** of selling my PSAs locally. I live in a pretty small town (50K people) and I don't know a single person who would even consider a Dayton 1200, let alone quad XS15s.

I really really wish I woulda done more research before my current subs (not that the PSAs don't rock...they do), but what's done is done.



I most certainly do not insist on Daytons - was just a crazy idea really. I think if I got 2 more XS15ses I'd be in bass heaven....I'll just have to save my pennies until I can get there! In the meanwhile, the system sounds pretty dang good....in my seat at least.
you don't need to sell locally. yes you will lose quite a bit in shipping but the four PSA sub's will net you enough to build 4 diy sub's. four martycubes would be a substantial improvement and four minimartys would be devastating. can do 4 martycubes for 1500$ and four minimarty for 1800$. you would gain 10 dB's across from 17-35 hz. cmon join the dark side
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post #11 of 40 Old 07-15-2014, 05:39 AM
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Quote:
Originally Posted by Alan P View Post
I really really wish I woulda done more research before my current subs (not that the PSAs don't rock...they do), but what's done is done.

I think all of us have felt the same way at one time or another.


I think you need to figure out what's going on in your room before buying anything else. I would start with one sub and take some measurements and see what issues you have. Then add one sub back in at a time and measure after each sub is added. My gut feeling is you have the right hardware, you just need to figure out how to set it up.
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post #12 of 40 Old 07-15-2014, 05:49 AM
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Alan,

It would be easy for you to add 2 more drivers at 60 Hz in your current system. You have Klipschorns, right? They'll easily do 60 Hz. Instead of crossing them at 80 Hz, try 60, or 50 or 40. It doesn't cost anything. Give it a try.

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post #13 of 40 Old 07-15-2014, 07:08 AM - Thread Starter
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Originally Posted by KidHorn View Post
I think all of us have felt the same way at one time or another.


I think you need to figure out what's going on in your room before buying anything else. I would start with one sub and take some measurements and see what issues you have. Then add one sub back in at a time and measure after each sub is added. My gut feeling is you have the right hardware, you just need to figure out how to set it up.
C'mon Kid, you don't think I've already done all that?

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Originally Posted by craig john View Post
Alan,

It would be easy for you to add 2 more drivers at 60 Hz in your current system. You have Klipschorns, right? They'll easily do 60 Hz. Instead of crossing them at 80 Hz, try 60, or 50 or 40. It doesn't cost anything. Give it a try.

Craig
Thanks Craig, that's a great suggestion! I've had my x-over set to 60hz before and didn't like the way it sounded so immediately dismissed it, but I've never made any measurements at 60hz. Gonna give this a go and see what happens!
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post #14 of 40 Old 07-16-2014, 06:04 AM
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Originally Posted by dsrussell View Post
If you mean less subs, it's worth a try. I don't see what a lesser sub would bring to the table. Before adding anything, have you thought about turning one of your subs off? It could be that one of the four subs is helping to cancel some of your frequency response. I'd try turning one off and keep switching which one is off until you've gone through all possibilities. Hey, it sure can't hurt to try.
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Originally Posted by KidHorn View Post
I think you need to figure out what's going on in your room before buying anything else. I would start with one sub and take some measurements and see what issues you have. Then add one sub back in at a time and measure after each sub is added. My gut feeling is you have the right hardware, you just need to figure out how to set it up.
agree with russell and kidhorn.

If you are not happy with the sound, it may be due to integration of the 4 subs, and the calibration of your entire setup. The more subs, the more risk of cancellation points.

Adding 1 lesser sub is unlikely to solve your problem unless you know what is the root cause of the problem. And my guess is that it is likely to make it even more complicated.

I am on multiple sub setup myself and my experience is that it is not so simple to integrate subs. REW FR is one thing only. But maybe at your MLPs, there are phasing and timing issues?

Can i suggest that you post your room layout, equipment, AVR settings, sub settings here? Then we can help u, better.

And.... what exactly is the observation that you are not satisfied with now? not enough rumble? not enough thump in chest? too muddy? pls share more.

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post #15 of 40 Old 07-16-2014, 07:52 AM
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Alan has already found the best placement for his subs. He has a thread with all the information. The setup that offers a flat response down below 20hz gives up some headroom compared to stacking them up front. However stacking them up front causes a 60hz null. I do not believe he stated that sound quality was a issue. The problem is 4 15" sealed subs are not enough fire power in a huge room (4500^3+)when placed accordingly to smooth the response.
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agree with russell and kidhorn.

If you are not happy with the sound, it may be due to integration of the 4 subs, and the calibration of your entire setup. The more subs, the more risk of cancellation points.

Adding 1 lesser sub is unlikely to solve your problem unless you know what is the root cause of the problem. And my guess is that it is likely to make it even more complicated.

I am on multiple sub setup myself and my experience is that it is not so simple to integrate subs. REW FR is one thing only. But maybe at your MLPs, there are phasing and timing issues?

Can i suggest that you post your room layout, equipment, AVR settings, sub settings here? Then we can help u, better.

And.... what exactly is the observation that you are not satisfied with now? not enough rumble? not enough thump in chest? too muddy? pls share more.
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post #16 of 40 Old 07-16-2014, 07:57 AM - Thread Starter
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agree with russell and kidhorn.

If you are not happy with the sound, it may be due to integration of the 4 subs, and the calibration of your entire setup. The more subs, the more risk of cancellation points.


Huh? I've always read that it is just the opposite....the more subs, the more room modes excited, the less cancellation.

Quote:
Adding 1 lesser sub is unlikely to solve your problem unless you know what is the root cause of the problem. And my guess is that it is likely to make it even more complicated.


It was 2 "lesser" subs....and, yeah I realize that it was probably a bad idea to begin with.

Quote:
I am on multiple sub setup myself and my experience is that it is not so simple to integrate subs. REW FR is one thing only. But maybe at your MLPs, there are phasing and timing issues?


You're telling me! I've had my PSA subs for almost a year and a half now and I'm still messing around.

When I had the subs spread out around the room, I had the ability to take care of all phase and timing issues with my MiniDSP. The only problem I had with them spread out was a lack of headroom.

Quote:
Can i suggest that you post your room layout, equipment, AVR settings, sub settings here? Then we can help u, better.

And.... what exactly is the observation that you are not satisfied with now? not enough rumble? not enough thump in chest? too muddy? pls share more.


My room setup is below, but now all 4 subs are up front in 2 stacks of 2 next to the KHorns.

My only complaint with the way it's set up now is that I have a ~10db null around 60hz and my other two listening positions aren't looking as good as they did when I had the subs spread out.

I'm going to try Craig's suggestion and lower the x-over on the Khorns. Gonna do some measuring tonight and I'll post 'em up here.

Room is about 5000 cu. ft.
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post #17 of 40 Old 07-16-2014, 08:02 AM - Thread Starter
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Quote:
Originally Posted by basshead81 View Post
Alan has already found the best placement for his subs. He has a thread with all the information. The setup that offers a flat response down below 20hz gives up some headroom compared to stacking them up front. However stacking them up front causes a 60hz null. I do not believe he stated that sound quality was a issue. The problem is 4 15" sealed subs are not enough fire power in a huge room (4500^3+)when placed accordingly to smooth the response.
Thanks BH, you're too familiar with my issues dude...maybe I just complain too much.

BTW, I'm flat ('cept for that little issue around 60hz) down to about 8hz now.

The wife was out for about an hour last night so I had some time to really crank it up and it was pretty impressive. Put in Pacific Rim and cranked it up to reference - absolutely no headroom issues, my chair was shaking like an earthquake and the hair on my legs and arms was moving along with my clothing.

I think I almost got it.

EDIT: And this was with the subs only running 4db hot. When I had them spread out, I had to bump them by 8db to get the tactile sensation I wanted.

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post #18 of 40 Old 07-16-2014, 08:04 AM - Thread Starter
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Oh, and I killed one of my overhead lights.

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post #19 of 40 Old 07-16-2014, 08:09 AM
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Huh? I've always read that it is just the opposite....the more subs, the more room modes excited, the less cancellation.
each individually located source will excite room modes differently but may also interact with the other sources to cancel those modes. This means you can end up using some of your output purely for cancellation purposes as opposed to useable output. You can get a brief overview of the mechanics here for example (there are no doubt other more detailed links).
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post #20 of 40 Old 07-16-2014, 09:45 AM
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Quote:
Originally Posted by Alan P View Post

EDIT: And this was with the subs only running 4db hot. When I had them spread out, I had to bump them by 8db to get the tactile sensation I wanted.

Why don't you spread them out and run them 8db hot?


It sounds like the problem is the gain is set too low.
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post #21 of 40 Old 07-16-2014, 10:25 AM - Thread Starter
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Originally Posted by KidHorn View Post
Why don't you spread them out and run them 8db hot?


It sounds like the problem is the gain is set too low.
They can't take it, not enough headroom.

If I never listened higher than -15db I'd be fine, but I'll be damned if I'm gonna do that!
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post #22 of 40 Old 07-16-2014, 10:53 AM
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Oh, and I killed one of my overhead lights.

Alan I think you got the answer, getting the wife out of the house, lol. My wife just looks at me some of the time when she comes home and I am watching movie near reference level, he , he.

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post #23 of 40 Old 07-16-2014, 12:06 PM
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Originally Posted by Alan P View Post
They can't take it, not enough headroom.

If I never listened higher than -15db I'd be fine, but I'll be damned if I'm gonna do that!

I guess if craigs suggestion of crossing at 60 doesn't work you need to add more subs.


The outlaw subs are on sale now.
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post #24 of 40 Old 07-16-2014, 01:21 PM - Thread Starter
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I guess if craigs suggestion of crossing at 60 doesn't work you need to add more subs.
Well, I don't NEED to but......
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post #25 of 40 Old 07-17-2014, 06:21 AM
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Originally Posted by basshead81 View Post
Alan has already found the best placement for his subs. He has a thread with all the information. The setup that offers a flat response down below 20hz gives up some headroom compared to stacking them up front. However stacking them up front causes a 60hz null. I do not believe he stated that sound quality was a issue. The problem is 4 15" sealed subs are not enough fire power in a huge room (4500^3+)when placed accordingly to smooth the response.
oic... thanks for explaining bh. can a kind soul pls post that thread url here pls... =)
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post #26 of 40 Old 07-17-2014, 06:52 AM
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Originally Posted by Alan P View Post
Huh? I've always read that it is just the opposite....the more subs, the more room modes excited, the less cancellation.

It was 2 "lesser" subs....and, yeah I realize that it was probably a bad idea to begin with.

You're telling me! I've had my PSA subs for almost a year and a half now and I'm still messing around.

When I had the subs spread out around the room, I had the ability to take care of all phase and timing issues with my MiniDSP. The only problem I had with them spread out was a lack of headroom.

My room setup is below, but now all 4 subs are up front in 2 stacks of 2 next to the KHorns.

My only complaint with the way it's set up now is that I have a ~10db null around 60hz and my other two listening positions aren't looking as good as they did when I had the subs spread out.

I'm going to try Craig's suggestion and lower the x-over on the Khorns. Gonna do some measuring tonight and I'll post 'em up here.

Room is about 5000 cu. ft.
Thanks! My room size is also around 4800 cubic feet. Using dual subs, 5.2 setup.

Can u share which AVR are u using?

And for the 'headroom' issue, could u help to describe/define a little bit more? Are u saying when there is a sudden demand of continuous heavy bass, you dont get that expected peak in thump/rumble? Thanks =)

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post #27 of 40 Old 07-17-2014, 08:50 AM - Thread Starter
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Originally Posted by sevenz View Post
Thanks! My room size is also around 4800 cubic feet. Using dual subs, 5.2 setup.

Can u share which AVR are u using?

And for the 'headroom' issue, could u help to describe/define a little bit more? Are u saying when there is a sudden demand of continuous heavy bass, you dont get that expected peak in thump/rumble? Thanks =)
Denon 2113ci.

I know I've ran out of headroom when I can hear the PSAs hitting their limiters (sounds like distortion/flapping drivers).



Had a revealing REW session last night....made me sad.

Graphs coming in a bit.
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post #28 of 40 Old 07-17-2014, 02:06 PM - Thread Starter
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OK, so last night I set up to do some measuring and to try some different crossovers on my mains per Craig's suggestion. Keep in mind this is the first time I've ever measured my mains by themselves...not sure why I'd never done it before, but whatever.

I found out that I'm sitting directly in the center of a giant 60hz null!

Check it out. This is just FL/R speakers, set to large, Audyssey off:



And here it is compared to some varying distances in front of my MLP. My MLP is currently 5' from the back wall where the picture window is:

2' in front of MLP - Magenta
3' in front of MLP - Blue
4' in front of MLP - Red



Smoothed to make it easier to compare:



Just to verify it's a null and not my speakers, here is the FR of the LFE only, same suck out right around 60hz:



So, it's no wonder I've been having headroom issues since Audyssey is boosting the sh*t out of 60hz....the distortion is 7.65% @ 60hz! Can't imagine how much amp power it's eating up for Audyssey to boost that region by ~10db. This is mains + subs, Audyssey on:




I tried moving the KHorns out of the corners about a foot or so and the null didn't change at all....seems like the only thing that is going to fix this is moving my MLP and that is just ruining my mood right now. The room just ain't gonna look "balanced" if I move everything forward (at least 2', but 4' would be better).

May have to think about rotating the whole setup so that the screen and mains are on the long wall....really don't want to do that though, it's a lot of work and it's really gonna mess with my feng-shui...especially if I end up in a similar situation and it was all for naught.

Not sure what I'm gonna do in the future, but for now I think I should run Audyssey a couple feet in front of the MLP just so it isn't boosting that null and straining my system.
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post #29 of 40 Old 07-17-2014, 08:32 PM
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Ahh yep I think you finally found the culprit. That massive boost in the 60hz is eating up some headroom. I think when you get that sorted and Audyssey does not need to apply so much eq, those 4 XS15's are going to sound night and day better.

I bet those Khorns will sound completely different too!! I have a pair in my shop office that is only 1200^3...needless to say they are amazing!! Wish I had the room for them in my house. They were a handed down from my grandfather along with a Adcom GFA-555II.
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post #30 of 40 Old 07-17-2014, 08:54 PM - Thread Starter
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Khorns too BH?? I swear, you could be my brutha from another mutha.
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