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Discussion Starter #1 (Edited)
:help: Just picked up a RS analog spl meter, and this is what I measured with 'C' weighting, slow response. I did not perform any adjustments and rounded to whole numbers for ease. I have the receiver performing crossover duties at 80hz and using an old SVS plate amp with a 12hz hpf engaged (cannot be undone and of unknown order). I would think I could boost the valley at 63hz, but I have no idea what else needs/should be done, especially with those nasty 88hz and 138hz canyons!
Any assistance appreciated!
 

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You haven't said whether you used a calibration file or not.

It's usually advisable to use a logarithmic plot rather than linear to display your graphs.

I would download one of our Excel sheets from the download site - (scroll down to 'Calibrating using the Manual method' and select the one for the meter you're using). They automatically adjust for the meter calibration and provide a log graph with an appropriate scale for subwoofers.

Here's the excel sheet for a newer Radio Shack Analog meter.

brucek
 

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Discussion Starter #4
The sub's unlikely to go anywhere- it's 7' of sono in the corner next to the couch and six feet away from the spl meter, and it's unlikely to move more than a few inches.

No mod to the anything-no calibration adjustment as I read conflicting things regarding the need for them.

Thanks, I'll have to try what you've suggested thus far and post back.
 

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Discussion Starter #7
I would ignore the dip at 138 Hz.
Do you have a phase adjustment on the sub amp? If you do it would be worth trying it in several different positions.
The amp I'm currently using until I build/buy a hpf has a phase adjustment, however, the pro amp I plan to use does not. Just to clarify, I'll be using the phase adj to try to minimize the 88hz node? If it works, I'll look for a hpf with phase adj.

I tried to verify the dip was a node by changing my crossovers on the receiver: mains from 80hz to 70hz, while sub from 80hz to 90hz. There was a slight increase in the amplitude in the big 88hz dip, with little or no change in adjacent frequencies. Do you think I should keep the new settings?

Otherwise, the response looks good, right? When I ran Audyssey, it had the sub output level 2 or 3 dB lower, but I raised it to the current level as I read others have done.

Thanks for your help guys.
 

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Discussion Starter #8
Uh oh. As I walk around the room, I have hot and cold spots all over, like swimming in the ocean :hush:
Phase adjustment had little effect on the spl measure at 80-100hz. I guess that's what happens when you have a LLT sub close to seating position:1eye: Would either another (smaller) sub in the opposing rear or front of the room cure this? Positions on different cushions on the couch even sound different.
 

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Room size and shape can give some nasty responses.
We are in a rental at the moment waiting for the new house to get built & my sub sounded great in the old house and terrible in the rental.
The rental has an open plan lounge/dining and offset kitchen.

What are the dimensions and shape of your room?
 

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Discussion Starter #10
I think I'm experiencing the same thing. Check out MY PHOTOS under my name and you'll get the idea of the 'room'. Not shown is the entire right wall from the listening position(8'x12' or 2.5m x 4m), which is only a railing to the entire downstairs below. There are three doors open to the room and of course the stairway below the tv in front. So, all kinds of open space. The doors are typically all open for air flow, but perhaps I should close one or more?
 

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Discussion Starter #12
Well, I tried changing the phase on the current amp and when I did, little change happened on the spl meter in the listening position, however, in the closet (behind the in-wall equipment rack) the sound level was definitely changing. I read that using another sub is usually not a good idea, but is it worth trying? I could place my svs cs12 in the opposite rear, or in the front corner next to the equipment rack.

On another note, if the rest of the response looks good, will I not have need of the eq function on the hpf that I have coming (Elemental Designs eq2), or benefit from a BFD?
 

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I read that using another sub is usually not a good idea, but is it worth trying? I could place my svs cs12 in the opposite rear, or in the front corner next to the equipment rack.

On another note, if the rest of the response looks good, will I not have need of the eq function on the hpf that I have coming (Elemental Designs eq2), or benefit from a BFD?
I think it's best to have matching subs and that helps smooth out the response. Having the eq is still a good thing even if you don't use it initially.
I don't have one but the BFD looks like it's a great little unit, with one you could try playing with housecurves - see Waynes article.

Also, I think you can put your graph into REW somehow and see what a BFD does for it. BruceK will know how to.
 
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