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4 STF-3's or 2 PB2-ISD's?

1043 Views 27 Replies 7 Participants Last post by  craigsub
Hi All:

I am moving into a new HT. My old theater was 2200 Ft^3 the new one will be 6700 Ft^3. I used to run 2 M&K MX 100's they are 200 watts each with 12" push pull drivers. They sounded great but I think they rolled off a little early so I was missing some of the really deep stuff. I will keep the M&K's and will be adding the new subwoofers to the system. The room will have 2 recliners and 18 theater seats on 3 risers. What do you guys think will give me the best, even, and deepest response 4 STF-3's or 2 PB2-ISD's?


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Neither. Response can't be predicted without the subs in your room and with that many, there is going to be a collision of sound waves that's going to be hard to tame. Personally, having SIX subs total is going to be a nightmare, yet alone four if you were to get the SVS'. I'd really get rid of the two subs you have now, and try to buy two high output subs. What those would be would depend on your budget.

I realize my room will play a large part in the performance but i was looking for opinions and I do appreciate yours. It seems to me after reading the HK white paper that 4 subs could offer an advantage over one. This would allow me to move the subs for best effect then move to an EQ. When I went from one sub to two I was able to get a much more even response in my old room. With the construction of the new theater I think my budget is limited to about $2,000 right now.


I don't think an IB will work. It is a basement theater with no useful adjoining spaces.

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I'm not sure of the used resale value of the M&K's, but just for ease of setup, I would say sell the two subs you have now and get two PB2+'s and tune them at 20hz. That should fill that room with low, clean bass. And you could split or stack em and see what work's best.

The reason I was thinking of keeping the M&K's it that they blend so well with my M&K sats. So I was looking for the M&K's to do the upper work and the new subs to help there and add the lower end. Is this faulty logic?
I think so. I would think many here would agree a good sub in GENERAL can blend with the majority of speakers out there with simple crossover, placement and calibration adjustments. Also, mixing subs means more difficulty in getting those two blend together as well. You're creating two blending points instead of one.

OK, I'll give it a try when I get the new subs and see if it sounds better without them. I once tried a big Velodyne and while it sounded very nice down deep it felt like there was a hole around the crossover point so I didn't get the nice punch from drums and the initial blast of an explosion. Since I have true sats, they don't do much below 80 Hz, I need something that is comfortable doing some of the higher base work. I have found the M&K's to work very well in this regard. I was sort of considering my M&K subs and the sats to really represent a full range speaker and I was adding a sub to that.

Thanks for your thoughts.
Well you know your equpment better than I, but if you can set your crossover to 100-120hz that should fill in nice but sounds may be more localizable. At the same time, if you have two subs that'll probably eliminate most of that problem. What is the crossover is now with the M&K's and with the Velo?
I have the crossover set at 80 which is correct for the sats I have, S100B's. I don't have the Velo I just tried it once some time ago, I had a smaller M&K sub that I was going to replace. After that experiment I went with the Bigger M&K and later added a second.

What you need are large drivers in large enclosures. To have output in a large room, there is no subsitution for size. If you can tolerate or hide large enclosures, I would look for one of the Internet boys build you a large ported box. Your budget you could perhaps buy 4 Styke AV12 EBS Tubes stacked or a couple of Adire Tempest.
Thanks rosros I will check them out.
F355: those look like some pretty big bad boys. I am not familiar with them but I will see what I can find out. What do you know about them?


all i know is that it uses [one of the] biggest baddest drivers around. the ADIRE TUMULT. just do a search for the driver and start from there.

happy researching... :)
Gary, Sounds like a great room ! Our theater room is 5700^3 feet, or about 85 % of the size of yours. We are currently running a single SVS 25-31 pc plus in that room. The sub has yet to bottom, nor are we lacking in any way bass.

Two things we did, after reading extensively some info from Stereophile regarding subwoofer placement... 1. We figured the room resonances 2. We moved the subs to behind the listening position, away from walls and corners.

Room resonace is easy... take speed of sound (1129 fps) divided by ( 2 x room dimension) ...

for example... our one wall is 25 feet... the other 24... and the cailing 9.5...

Resonance 1 : ... 1129 / (2 x25) = 22.58 hz

Resonance 2 : ... 1129 / (2x24) = 23.52 hz

Resonance 3 : ... 1129 / (2x9.5) = 59.42 hz

Without getting too bogged down in details, they suggested that, in any room with a dimension over 18 feet should not use a corner placement... When I moved the sub away from the corner, right behind the listening position, the difference was amazing !

It pretty much eliminated the resonance in the 23 HZ band... and you cannot tell the subs are behind you. I have had guests think I was pulling their legs when telling them there were no subs up front. Interestingly enough... when I sent Hsu research my room dimensions, they concurred with the placement, as did Tom V. from SVS...

For your room... I can positively tell you a pair of SVS PB-2 + will do everything you want and more. remember, it really is four subs, without the complexity of four boxes.

I have some Hsu subs on order, and cannot tell you anything first hand yet... but they are really well known for a great product. But again, four boxes will be tough... phase matching.. etc..

as for the "custom" and "diy" stuff... much easier said than done... Our familt manufactures pro-audio speakers, including subs... it is very complicated getting enclosures right... etc...

Have fun with this...
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Wow craig thanks for the info.

I wasn't going to corner load the subs or collocate them which is why I am going to need a bit of power. I guess I could consider popping up to the PB2+'s and consider retiring my M&K subs. Having never heard the SVS's I guess I am just concerned they will be able to do the upper base work as capably as the M&K's subs. My intended position for the new subs was behind the listening position with the M&K's in the front.

Since we have fairly similar sized rooms any other set-up advice you have will be gladly accepted.

After putting some thought into this... I would think that the PB-2 +will handle up to 80 Hz nicely, as from that frequency and lower sounds are hard to locate, as long as you Sats are strong to 80 Hz...especially if the subs are behind the theater seats...

Have you decided on a pre-amp processor or receiver ? Because if you have, and as suggested above, it has a 100 HZ crossover availability, you should be all set...

And for a project this size, you would do well to e-mail Tom V. at SVS ... give him the room dimensions, etc... and see what he says...

I would also do the same with Hsu... and get their feedback. They may have some ideas about putting four subs together.

Both companies are tremendous, especially at helping people out...When a company allows 45 (SVS) or 30(HSU) days use in your home with 100 % return... they are confident and very unlikely to give bad advice....

My experiences so far have been positive

I have heard M&K in other settings.. and you are in for a real treat...
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Thanks craig:

Actually I have contacted both companies and the posted subs are the ones they recommended so I was just looking for some comments on their suggestions. I can cross over anywhere from 120-40 so I will have a chance to experiment, the M&K suggestion is 80 and that is where I run them now.

Thanks again.
Gary, Perfect... it is great to get to get info right from the designer of a product... yes ?

WOW ... and Dr. Hsu suggested 4 subs... He thought I only needed two, now I have room envy....:D

Either way you go your system will be fantastic ... the crossover flexibility should handle everything for you...

So ... How long until your project is done ?
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