Single vs dual subs

I would go with the dual PB12-NSDs. That way you can move them around to flatten out your in-room frequency response.

OTOH, you could always get one PB12-Plus now and another one later on if needed.

I don't think it's worth your time to go from a VTF-2 to dual PB12-NSD, you would probably get similar results by just adding another VTF-2 which is on sale right now.

Why don't you just keep an eye out on the SVS B-stock section and pick up an Ultra for $1399 + shipping, I see them come and go all the time.

Epik Empire! Dual 15" drivers in single box with 600 watt bash amp, http://www.epiksubwoofers.com/empire.html. Also, read what customers had to say: http://www.epiksubwoofers.com/reviews.html.

I have dual Empires, Bill

seriously, look at epik empires. i've been researching for 6+ mo and never found any other sub company that offered dual 15"s for that price. finally bought 1 last wk and should arrive next wk.

The 5.25-inch drivers on your Totems will probably blend more seamlessly with a 12-inch driver on a sub than a pair of 15-inch drivers. To that end, instead of getting two PB12-NSD subs, I would save $700 and get another VTF-2 (especially since it is on sale).

I'll be the dissenting voice here. Though you can smooth the modal response by adding a second sub, I'm afraid that you might do more harm than good by putting that much more low frequency energy into the room. I mean, dual 12's is a lot for that size room. You're dealing with a low ceiling and a relatively narrow width with respect to the length. Just something to think about.

Frank

Too much LF energy may not be a problem, especially when the subs are spread apart for mode cancelling rather than co-located for more bass. Take a look at pages 19 & 20 of the Harman whitepaper on subwoofer placement. The graph on page 20 shows the results of various subwoofer configurations. Notice that adding subwoofers generally resulted in less LF (white line). Also notice that some configurations (#6, #10, #11, #12) produces amazingly little seat-to-seat variation in bass response (blue line). And this is without the benefit of treatments and room correction/EQ.

nhbearsfan34, what is it your looking for in a sub(s) performance for around $1400 that your not getting with the HSU VTF-2? My first inclination would be to recommend buying another HSU VTF-2. But if you want a change and are going to place your Totem Mite T on them, you'd want a sub that dosen't resonate with HT material (Epik Empire) or else they'll be sliding off or moving.

Huh? Why would that be?

If he calibrates the duals to the same level as he had calibrated his single previously, why would he be adding any more bass, (or "low frequency energy" ask you call it), into the room? He'll have more headroom, lower distortion and the potential for smoother frequency response, but if he doesn't turn his system up any louder, he won't be adding *any* more "low frequency energy" into the room.

Craig

This doesn't make any sense.

Subs dont "blend" into anything...they merely reproduce an audible frequency.

Timbre matching of different size drivers across the crossover point. Going from a 5-inch driver to a 15-inch driver within a few Hertz can be noticable, especially when playing slow sweeps. The less audible you can make it, the better.
You've really never heard of "blending" the splice between a subwoofer and speaker?

but what is different? Group delay, stored energy.

I never read any discussion about the size of a woofer matching the size of mains. Not one DIY expert, not one speaker building expert.

So do you have any links showing the measured differences?

I would say using 2 subs will definetley flatten the frequency response but my question is i am using a Velodyne at the moment if i bought an Svs would that give same results as oppose to using 2 velodynes that is why been holding off buying another sub.

Regards Lino.

Size. Amount of air moved. Or are you saying that 80Hz produced by a 5-inch driver sounds the same as 80Hz produced by a 15-inch driver?
When I was ordering a pair of Rythmik DIY sub kits and trying to decide between the 12-inch and 15-inch drivers, the first question I was asked was the size of woofers on my speakers. Didn't surprise me, since this wasn't the first time I'd been asked about my mains when buying a subwoofer.

???????

???????


Have you ever used dual subs? "Measured differences" are you serious?
When you listen to music do you hear fractions?
The sub's woofer size definitely has a role in the overall cohesiveness (of music more than movies). A subwoofer sized too large for the main's sounds lopsided even when peq'd.

You cant timbre match a sub because there is no timbre to matched.

The size of the woofer means NOTHING in the world of "blending" with a speaker AT ALL. ZILCH.

Again, a subwoofer does one thing: reproduce low frequency. Nothing needs to be "blended".

All we are asking for is proof of this hypothesis. However, I can tell you that your hypothesis is leaning towards the null kind.

You've never tried integrating a sub with an electrostatic speaker.
In that case, what blending are all these folks talking about?

http://www.avsforum.com/avs-vb/showp...postcount=6710

http://www.avsforum.com/avs-vb/showp...&postcount=984

http://www.avsforum.com/avs-vb/showp...ostcount=10217

http://www.avsforum.com/avs-vb/showp...27&postcount=8

http://www.avsforum.com/avs-vb/showp...9&postcount=16

http://www.avsforum.com/avs-vb/showp...postcount=5631

http://www.avsforum.com/avs-vb/showp...postcount=8355

http://www.avsforum.com/avs-vb/showp...&postcount=793

http://www.avsforum.com/avs-vb/showp...ostcount=22045

http://www.avsforum.com/avs-vb/showp...ostcount=22406

It makes ZERO difference what kind of technology the speaker is using.


LOL....thats your proof?

Just because a FEW people talk about something, doesn't make it correct or even real. Scientific evidence > a baseless opinion; thus, two separate people asking for PROOF. A bunch of non-qualified, anonymous posters on a message board does NOT qualify as such.

Its one thing to BALANCE a sub with your mains (too much bass can over power the overall sound), but that's not what the other guy in this thread was talking about. He said that a certain size sub wouldn't "blend" well with a certain size of main, which is asinine.

PS - A bookshelf speaker with a 4" mid-driver will "blend" just fine with a 18" subwoofer.

I just assume you guys are talking about the BlendTec youtube videos. If so, I don't think even the 12" would blend.

Chris is the chief technical officer of Audyssey, Dave is owner/designer of Ascend speakers, Marc is an Emmy award winning sound mixer, Roger is an EE and used to be director of technology strategy at Dolby. They're hardly "non-qualified, anonymous posters".

There are others, like Earl Geddes and Brian Ding, who go through significant efforts to get a smooth and seamless blend between speakers and subs. In fact, Brian has 3 pages at his Rythmik site dedicated to using phase and delay to get a better integration: http://www.rythmikaudio.com/phase1.html
Then we have different ideas of "fine".

At a low level, at, say, 100Hz, what's so different about a 5" woofer and an 18" woofer? Provided they're both behaving linearly enough, they're both monopole point sources feeding what is most likely the room's modal region. That proviso is the catch, though, as once you turn up the level, the 5" is likely giving up the ghost at a pretty mundane level.

"Timbre" at what sound level? Sometimes, numbers matter...

I am looking to add another sub to my theater and currently have a SVS PB12 NSD/2. Are there general rules about adding another sub (i.e. avoid mixing ported and sealed, size differences, etc) that I need to consider or can read about somewhere? I would like to add a smaller (i.e. single 10" or 12") and would prefer to spend <$500. Thanks!

-Jason

Best thing to do is measure what you have from the listening position, and figure out what it is you're missing. If you have a cancellation near the bottom end of the range, you'll need something roughly the same size/output. If it's higher up the range, a smaller sub should work just fine.

Sdurani,

Thanks for the link to the Harman paper on #/placement of subs--a very informative virtual and real room study of the subject, I appreciate it!

Cheers,
XEagleDriver

Just to add further to the concept of blending.

In car audio picking drivers that match well is a huge thing, especially in IASCA matches at the expert level. A 6" driver will handle frequencies different than a 4" driver (or a 5" driver for that matter) in any given situation (all other variables being the same). You will have peaks and dips at different locations and because of this it is generally easier to get a better flat scale reading (having a reading that is completely flat with no dips/peaks in the frequencies from 20Khz-20hz) when picking speakers that match each other and "blend" well. That being said it's not impossible to get a system that isn't matched well to not work, it's just generally harder. This is also part of a strict sound quality judging and most normal people probably couldn't even hear the minute differences the judges see on their meters when testing this portion.

So yes there is "blending" or "sound matching" whatever you want to call and plenty of professionals talk about it (otherwise you'd see a bunch of tower speakers with a pair of 18" woofers and 4" mid-range with a .75" tweet). Granted this is coming from someone who has worked, and built cars, in the car audio industry for the last 15 years so I'm fairly certain the same basic concept works in home audio.