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Mismatched Subwoofers

SimpleTheater

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I’m still using a PSB Subseries 9 subwoofer and was hoping to replace it with two Rythmik subs (I do not have room for three or four subs). My dilemma is there is virtually no market for a used PSB 9 subwoofer in which, after shipping/eBay & PayPal fees, I end up with anything more than $150, and it’s too good a sub to let it go for that type of money. So is it a mistake to mismatch my subs? I’m looking at the Rythmik FV15HP, a 15” ported unit capable of getting down to 12hz-15hz, whereas my PSB is rated at 28hz.

My Yamaha RX-A3060 has two sub outputs and it can set separate parametric eq’s for each sub.

By getting only one Rythmik I lose out on the discount, so getting just one and finding out I need two is like throwing away $140.
 

raistlin65

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I suspect you might choose not to use the Subseries 9 once you hear the FV15HP.

How big is your room, including any open adjacent areas? You might save a little money and get dual FVX15s. Then keep the Subseries 9 for a bedroom or desktop setup.
 
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SimpleTheater

SimpleTheater

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I suspect you might choose not to use the Subseries 9 once you hear the FV15HP.

How big is your room, including any open adjacent areas? You might save a little money and get dual FVX15s. Then keep the Subseries 9 for a bedroom or desktop setup.
The room is 23 x 15 x 10. All the equipment (except surround and ceiling speakers) sits behind an acoustically transparent screen. It is a completely separate building, detached from the house. It has no windows, just an entrance door.
 
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raistlin65

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The room is 23 x 15 x 10. All the equipment (except surround and ceiling speakers) sits behind an acoustically transparent screen. It is a completely separate building, detached from the house. It has no windows, just an entrance door.

In that size room, the Subseries 9 wouldn't come close to keeping up.

That being said, for that size room, dual FVX150's or Power Sound Audio V1512DF's would pound. Tom Vodhanel, the owner of Power Sound Audio, is one of the original founders of SVS and a good guy to work with.

My guess is that Tom would let you order a V1512 or V1512DF and would give you a few weeks if you wanted the second at whatever his two sub discount is. You should shoot him an email.
 

Bear123

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The problem with mismatched subs is two fold....first, there can be cancellation around port tune as the subs will be out of phase with each other. In that size, room, dual FV15HP's would not be overkill imo unless listening levels are very low. But, since you have a dedicated separate home theater space, I'm guessing its not for watching TV sitcoms at -30 dB.

Secondly, the 10" sub is going to crap the bed WAY before the FV15HP. So whatever combined response you get with the pair, is going to vary drastically once the little 10 falls down.

You could always order the first and still get the discount on the second if you order within a certain time frame.

For what its worth, I have a pair of FV15HP's and would rate them a 10/10 for movies in my 2525 ft^3 room.

I also would not rule out the FV18 and PSA TV18(which you might still be able to sneak in pre-order pricing)

Can you repurpose the other sub for the main house secondary system? Garage? Workout room?
 

StevenEleven

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I’m still using a PSB Subseries 9 subwoofer and was hoping to replace it with two Rythmik subs (I do not have room for three or four subs). My dilemma is there is virtually no market for a used PSB 9 subwoofer in which, after shipping/eBay & PayPal fees, I end up with anything more than $150, and it’s too good a sub to let it go for that type of money. So is it a mistake to mismatch my subs? I’m looking at the Rythmik FV15HP, a 15” ported unit capable of getting down to 12hz-15hz, whereas my PSB is rated at 28hz.

My Yamaha RX-A3060 has two sub outputs and it can set separate parametric eq’s for each sub.

By getting only one Rythmik I lose out on the discount, so getting just one and finding out I need two is like throwing away $140.

I would say order the Rythmik and try it with your other sub. The proof will be in the pudding—use REW to see what kind of response you are getting and see if you can clean up the room modes one way or another in the range you are running them. Otherwise you are just grasping at straws, IMHO.

This part requires work and experimentation and learning, there is no magic bullet technique or piece of hardware, IMHO. You can spend a zillion dollars on two beautiful matched subs and not put the work in and totally screw everything up or probably get one more sub and smooth it all out quite a bit even if the subs are “mismatched.” I don’t see why it wouldn’t work but the fact is it either works or it doesn’t and if it doesn‘t you will see if it works or not by moving your subs around and measurements and applying any DSP you use and measuring in probably a trial and error process. Nice smooth extended bass is definitely cool but it can be a formidable challenge.

For example, my room has a couple of MASSIVE room modes from well below 20 hz to 30 hz to 60 hz so the trick for me is massively smooshing the room modes down with DSP. Otherwise a pin drop sounds like a nuclear explosion! I use an old Behringer DEQ2496 to even that out. REW generated recommended filters and I used that as a baseline. Given my room gain, for me power of the subs is just not an issue, the room provides all the gain I could ever want and then some and then some. Without DSP I am at plus 15 dB at 20 hz and 30 hz!!! Plus 10 dB at 40 hz! And up 5 dB at 50 hz. Then a big narrow dip centered at 74 hz. With DSP and experimentation I am pretty much even and flat down to 20 hz.

Mind you, I spent many many hours obsessing on this and will spend more hours because it is interesting and challenging. Have you taken measurements with your sub engaged to see what your biggest bass issues are? That will help you make informed decisions. Until then your are dealing in wild speculation IMHO and you spend additional $$ without knowing enough about what you are trying to accomplish. :)
 
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Ivanovich

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I’d go for the pair of matched subs.

Maybe you can repurpose the PSB to use as a 2.1 with some cheap speakers for background music in the main house somewhere, to at least get some use out of it. You can also pass it on. I gave some of my old shit to my sister-in-law as upgrades to the Walmart junk she had. It felt better than getting a little money.

I have a pair of ancient 12-in Velodyne F-1200 in a similar size room, but really larger because it is open to other rooms and the upstairs. I have them in the corners nearest the mains and don’t feel like I need 15” or 18” subs to play loud and low enough.

I don’t know, but it would seem to me that if two subs are ported and not identical, you could have phase problems.
 
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SimpleTheater

SimpleTheater

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Have you taken measurements with your sub engaged to see what your biggest bass issues are? That will help you make informed decisions. Until then your are dealing in wild speculation IMHO and you spend additional $$ without knowing enough about what you are trying to accomplish. :)
While the PSB isn't spec'd below 28 Hz, it does get down to 20 relatively well. I haven't dealt with the peak around 40-50 yet, or other issues, because if I get a new sub (or two), I'd end up spending hours dealing with these issues all over again. I want to get some thunderous bass down to 10 Hz.

PSBSubSeries9_10hz-200hz.jpg
 
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SimpleTheater

SimpleTheater

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But, since you have a dedicated separate home theater space, I'm guessing its not for watching TV sitcoms at -30 dB.
:)
Secondly, the 10" sub is going to crap the bed WAY before the FV15HP. So whatever combined response you get with the pair, is going to vary drastically once the little 10 falls down.
Yes. Below 20 Hz I'd basically be playing with one sub, since the PSB can't get that low.
I also would not rule out the FV18 and PSA TV18(which you might still be able to sneak in pre-order pricing)
Unfortunately I'm limited to 18" width on the subs, without putting in weeks of labor re-configuring the equipment/stands.
Can you repurpose the other sub for the main house secondary system? Garage? Workout room?
Unfortunately not yet. I have a dedicated stereo listening room which already has my sub of choice.
 

Bear123

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:)
Yes. Below 20 Hz I'd basically be playing with one sub, since the PSB can't get that low.

Unfortunately I'm limited to 18" width on the subs, without putting in weeks of labor re-configuring the equipment/stands.
Unfortunately not yet. I have a dedicated stereo listening room which already has my sub of choice.

Understood on the size. That prevents me from the 18's as well.
 

CDMC

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I will put in my two cents given I am prone to not wanting to waste a perfectly good item. Since you do not have a use for the subwoofer and it serves no purpose in your current system, sell it for the price you can get for it. The alternative is you will end up sticking it away where it will devalue to nothing. Sell it on your local Craigslist, where it will enjoy another life in someone else's home. You will quickly discover that the only things that your old PSB and the Rythmik share is the name subwoofer.

Get the two subwoofers to start with. Do this for a couple reasons. First, and perhaps most important is that having two will help to lessen the seat to seat variance in bass, which can be 20 db or more. Second, when you start discussing sub 20hz bass, you need a lot of lot of output capability. Two subs will get you between 3 to 6 db more output. At less than full output, they will have lower distortion.

You may want to post your question on AVS forums subwoofer forum. They are helpful, have a ton of data, and many use Rythmiks. Just don't be surprised if they come back and tell you if you want to reach reference levels you will need 4 subs.
 
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SimpleTheater

SimpleTheater

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I first want to thank everyone for their input. Regardless if your opinion was to keep my sub or get rid of it, each opinion made me think and made my final decision a better one. There is no doubt that two matching subs are better, especially when one can go lower than the other, leaving it by itself in that range.

After reviewing my subwoofer REW measurements and rerunning some tests, the PSB holds it’s own well enough above 20 Hz and by itself it can almost reach reference levels above 35 Hz and it shakes my riser well. This effect will only be better with a Rythmik FV15HP or two. I will definitely have difficulty smoothing bass between 10 Hz and 25 Hz, but that is an issue for movies/tv of a specific variety. If mismatching was a terrible idea, like a PSB center channel and two Klipsh L/R speakers, this would be a complete no-brainer.

Obviously the decision is a price/value proposition. The final cost difference is about a thousand dollars more for two Rythmik minus the PSB resale value. Bill Gates wouldn’t have a difficult decision. I’m trying hard to find a reason to keep the PSB because it exceeds its original specs and has been so reliable for 13 years now, almost like an old friend.

I’m thinking of reconfiguring my room to hold 3 subs. Too many decisions.
 
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