F-mods?

[speakerman39]

I have just recently purchased an SVS PB10-NSD and have it in a corner closest to my seating position for nearfield placement. I use a Y-adaptor out of my sub pre-out on my Pioneer 1015 and run one side to my PB10. The other side I run into (1) of my Acoustic Research 8" subs that is placed in the front left corner. My AR 8" sub has a pass-thru and that is how I feed the other AR 8" sub that is located in between my tv stand and my front right tower speaker. My room is approximately 13X20X7.25 feet. My seating postion is opposite the 20' wall at about 9' from my tv screen. I have put an in-line a 20 Hz High Pass F-mod to filter out anything below 20 Hz at 12 db/oct and put a 30 Hz High Pass F-mod in-line to my AR 8" sub at 12 db/oct. I have noticed that it really did tighten up the bass a bit with respect to the PB10 BUT it seems to take a lot from the AR 8" subs. Not really sure why that is-anybody here have any idea(s) what it could be? The idea was to make the PB10 a bit more musical by filtering out anything below 20 Hz and the same holds true for the AR 8" subs w/the exception of anything below 30 Hz. My 1015 is X-overed at 80 Hz so the PB10 plays 20-80 Hz and the AR 8" subs play 30-80 Hz. The overlapping does not seem to cause any problems from what I can tell so far. Please help if you can offer some tips.

 

[tdamocles]

I have just recently purchased an SVS PB10-NSD and have it in a corner closest to my seating position for nearfield placement. I use a Y-adaptor out of my sub pre-out on my Pioneer 1015 and run one side to my PB10. The other side I run into (1) of my Acoustic Research 8" subs that is placed in the front left corner. My AR 8" sub has a pass-thru and that is how I feed the other AR 8" sub that is located in between my tv stand and my front right tower speaker. My room is approximately 13X20X7.25 feet. My seating postion is opposite the 20' wall at about 9' from my tv screen. I have put an in-line a 20 Hz High Pass F-mod to filter out anything below 20 Hz at 12 db/oct and put a 30 Hz High Pass F-mod in-line to my AR 8" sub at 12 db/oct. I have noticed that it really did tighten up the bass a bit with respect to the PB10 BUT it seems to take a lot from the AR 8" subs. Not really sure why that is-anybody here have any idea(s) what it could be? The idea was to make the PB10 a bit more musical by filtering out anything below 20 Hz and the same holds true for the AR 8" subs w/the exception of anything below 30 Hz. My 1015 is X-overed at 80 Hz so the PB10 plays 20-80 Hz and the AR 8" subs play 30-80 Hz. The overlapping does not seem to cause any problems from what I can tell so far. Please help if you can offer some tips.

I'm not sure about this but the pb10 may have a HP filter built into the amp @ 20hz...Maybe the AR subs response after 30hz falls off quickly?

 

[tonay]

From what I've read, syncing 2 subs that are not matched is really tough.

Good luck on that

 

[speakerman39]

I'm not sure about this but the pb10 may have a HP filter built into the amp @ 20hz...Maybe the AR subs response after 30hz falls off quickly?

I am sure they do fall off rather quickly BUT they are rated to play down to 28 Hz. However, there is no indication at what db level. The PB10 does have a limiter built in but wanted to make it a bit tighter and it seems to work fine. The AR 8" subs seems to sound blanketed if you will. I am dumbfounded.

 

[speakerman39]

From what I've read, syncing 2 subs that are not matched is really tough.

Good luck on that

This is so true but seem to be good at doing this. Well, at least for my tastes anyways.........LOL!!!!! I may leave the F-mod on my PB10 and take it out of the path of the AR 8" subs. Kinda late tonight will have to do it tomorrow and get it dialed in right.

 

[j_garcia]

The PB-10 basically starts rolling off at 18Hz and is around -5dB at 16Hz, so I don't see where an F-mod at 20Hz is really helping you.

 

[speakerman39]

The PB-10 basically starts rolling off at 18Hz and is around -5dB at 16Hz, so I don't see where an F-mod at 20Hz is really helping you.

Hi John I read in a comparsion by Wayne A. Pflughaupt on another forum (hometheatershack.com) when he used a 25 Hz subsonic filter it improved the musical performance of the PB10 quite significantly. So, I decided to give the 20 Hz F-mod a shot as Harrison Labs does NOT make a 25 Hz F-mod. They do make, however, a 30 Hz and I thought this to be a bit too high for the PB10 but figured it would work fine with my AR 8" subs. You see, one must purchase a set of the F-mods at a time so I ordered (1) 20 Hz High Pass and (1) 30 Hz High Pass. I am still experimenting to see if it really helps or not. It does seem to tighten things up a bit on the PB10 but the AR 8" subs that is a different story. These little
8's are bulit like tanks and are extremely musical. They also do well w/HT. Just trying to get them to mesh together. May be a few weeks before I draw upon any conclusions.

 

[speakerman39]

Hey people I took the 30 Hz F-mod off the AR 8" subs and man things improved a lot. I then adjusted the phase on the PB10 and these subs blend seemlessly. I have decided, for now at least, to leave the 20 Hz F-mod on the PB10 as it seems to tighten it up a bit. That is, the PB10 seems to be a little better musically speaking in that it is noticeably tighter w/more definition. I will now focus on the PB10 tomorrow and listen to it w/o the F-mod where it is located now. Then, I will be able to decide if I should use the 20 Hz F-mod or not. May send them back and get my money back if I can. Just thought I would post an update.

 

[speakerman39]

For those whom may be interested I thought I would give an update. As mention in my previous post I took the 30 Hz F-mod off my AR 8" subs and things improved a lot. Then, I adjusted the phase on the PB10 and once again things improved dramatically. Although I did not get to do much tweaking today I did adjust the phase on the PB10 a bit more and all I can say is WOW!!!!!! I can say that I now have all (3) subs working extremely well together. The sound is so balanced and yet very articulate and punchy. My next step is to take the 20 Hz F-mod off the PB10 and see if things sound with a bit more critical listening. I know the PB10 is well behaved so to speak BUT from what I can tell so far the 20 Hz F-mod at 12 db/octave makes it behave even more. Unfortunately, the 30 Hz F-mod did NOT do much for my AR 8" subs. Hope to be able to do some critical listening and determine if I shouldd continue to use the 20 Hz F-mod on the PB10. When I do, I will post one last update for those who may be interested.

 

[speakerman39]

Well for anyone whom may be interested thought I would one last time report my findings. If you read this thread then you know that I have (2) Acoustic Research 8" powered subs and just recently purchased a SVS PB10-NSD 10" sub. I have been trying to integrate them by experimenting with placement AND by using a 30Hz F-mod high pass filter at 12 db/octave on the 8" subs while using a 20 Hz F-mod on my PB10-NSD respectively. However, after much trial and error and doing some critical listening I have concluded that the F-mods are really of no use to me. I also have used the phase control on the PB10 which imroved things some BUT not as much as one would think. So, decided to just take the AR 8" subs out and to my surprise the PB10-NSD really came to life so to speak. I mean the bass is unbelievable to say the LEAST!!!!!! I use to own a Mirage S12 and although it was an awesome 12" sub, it does not perform as well as the PB10 inmho. I am still calibrating somewhat with the Rives Test CD2 and Avia but so far I am amazed with the PB10. My point is this, guess integrating 3 powered subs proved to be more difficult than I originally anticipated. However, I have learned that placement can really make a difference. I now have the PB10 in the front right corner closer to my Infinity Primus 360's. It appears that there was a lot of low frequency cancellation when using all 3 subs. By keeping it simple and thus only using the PB10, I have managed to get the kind of performance that I want. Believe you me-the PB10 is doing it gracefully.