I need Multi-Sub assistance.

[bigpants_ku]

I've got a 10" Mirage ported Sub that's about 8 years old. I like it.

I've
just moved and my new HT is twice as big as my old one, and I fear the
10" won't be what I want/need (<--who can tell the difference
between "want" and "need" in this hobby, anyway?).

At
first, I
was just going to replace mine with a huge ported sub, but then I
decided to be an adult, and do some research. Over the last few
days, I've been fortunate enough to make it to a few high-end stereo
shops and try out several subs.

I've
been listening to some sealed and ported subs, from Martin Logan,
Klipsch, Velo, etc etc. I found that like the accuracy and punch
of the sealed subs, but I also like the depth and "acoustic
persistance," if you will, of the ported subs.

I'm seriously
thinking about running one of each in my new HT when I get it done, so
as to enjoy the acoustic benefits that each has to offer, and I know
others out there do the same thing for the same reason.

Here are my questions:

1)
If I do one of each, should I just keep my 10" Mirage, or will I be be
missing the lows in my new big room, and need to just go get a RT-12d?

2) If I do run two subs, how do I hook that up, there being only one SW pre-out on my AV Receiver?

Thanks!

[sivadselim]

2) If I do run two subs, how do I hook that up, there being only one SW pre-out on my AV Receiver?

You simply use a Y-adapter.

[bigpants_ku]

That's what I figured, I just wanted to be sure. Is that what everybody else does?

[sivadselim]

Is that what everybody else does?

That's what the (very) large majority use. Some subs do have a pre-out pass-through but I've always heard that it's actually better to just use a Y-adapter. If there is no pass-through, then you have no choice but the Y-adapter. It works fine.

[mas]

...you would do much better by having them each reproduce a different passband.

Otherwise a single larger more capable sub would be preferable.

[sivadselim]

...you would do much better by having them each reproduce a different passband.

Not sure what you're saying, but if you mean letting one handle upper bass and the other lower, this is pretty hard to implement. Would require a high-pass filter on the upper end sub.

[mas]

...you would do much better by having them each reproduce a different passband.

Not sure what you're saying, but if you mean letting one handle upper bass and the other lower, this is pretty hard to implement. Would require a high-pass filter on the upper end sub.

Actually its pretty simple.

Some quality subs have a high pass filter controlling their low end rolloff.

If not, a Rane 2 or 3-way crossover can easily be had for ~$100-125.

Otherwise, without going into all of the issues inherent with multiple sources reproducing the same passband, you simply open another can of worms that can easily become much more problematic than your original issue of insufficient gain.

It sounds like you would be better off simply getting a single more substantial sub capable of producing adequate gain for the space.

[sivadselim]

Actually its pretty simple.

Well............................ the idea is simple. It's the implementation that can be difficult to "dial-in".

Some quality subs have a high pass filter controlling their low end rolloff.

True, but that fixed high-pass filter is usually near the low-end capabilities of the sub and would be too low to use as a high-pass in this instance unless, of course, it is adjustable to a relatively high value.

If not, a Rane 2 or 3-way crossover can easily be had for ~$100-125.

Yep. You could even use a cheap, in-line RCA-type high-pass filter of fixed frequency to do it. But the exact implementation and proper calibration of this sort of setup is still difficult and I wouldn't recommend it for a novice.

Otherwise, without going into all of the issues inherent with multiple sources reproducing the same passband, you simply open another can of worms that can easily become much more problematic than your original issue of insufficient gain.

It sounds like you would be better off simply getting a single more substantial sub capable of producing adequate gain for the space.

I agree.

[mas]

Just a minor comment:

quote user="mas"]... a Rane 2 or 3-way crossover can easily be had for ~$100-125.

Yep. You could even use a cheap, in-line RCA-type high-pass filter of fixed frequency to do it. But the exact implementation and proper calibration of this sort of setup is still difficult and I wouldn't recommend it for a novice.

You would need more than a simple passive high pass filter. And there would be NO electronic setup or signal alignment possible if that scenario were to be employed...so the irony is that this option is extremely easy to implement, albeit very limited in effectiveness.[]

The primary impediment to a separate active crossover is potentially the cost of a separate amp for a passive sub and the cost of the crossover. The configuration of an agile active crossover point, slopes and alignment for a sub is actually rather simple due to the relative wavelengths involved (unlike mid and high frequency drivers).

This would be the optimal configuration for dealing with multiple disimilar subs, as mixing dissimilar subs to reproduce the same passband has fundamental problems.

But, to return to what I would suggest as the easiest and most optimal configuration in a normal home environment, (and certainly if you are not equipped nor prepared to address thes aforementioned issues), the best most user friendly and effective option would still be to go with a single more capable sub.

[bigpants_ku]

Thanks for your help guys! I'm definately a novice when it
comes to setting up subwoofers. But then again, I was once a
novice at tying my shoes (forgive the unfair comparison). My
point is that I can learn what needs to be done to optimize the sub, if
it's worth taking the time to learn (substantial noticable sound
difference). If I can figure that out with this thread, then I'll
take whichever route you experts recommend.

I agree with you both that just getting a bigger sub is the
*easier* route. But if I can get the quick punch of the sealed
subs I demo'd last week and the boom of the ported ones, then I'd be
willing to get whatever equipment, $150 crossovers, etc that I need to
setup and run them both effectively. Or if there's a
bigger/better option in a single sub that would give me both benefits,
I'd try to find room (ie THX120s and amp, RT12d, etc).

So I guess this is the essential question:

"Does
buying a smaller sealed sub AND a larger ported sub PLUS taking the
time to learn the proper calibration of the two (and buying the
equipment/crosovers) produce a sound worthy the time, money and effort

OR

Should I just get a new big sub/subs (and if so, any recommendations?) "

Thanks again!

[CECAA850]

Simply put. 2 dissimilar subs will have a certain degree of overlaping frequencies. For arguments sake lets say the ported sub goes lower and the sealed sub sounds better in the upper subwoofer range and reaches up a little better. The frequencies that both play at will be louder than when the 1)ported sub out extends the sealed down low and 2)when sealed sub reaches up higher than the ported . Basicly if you ran a frequency sweep, starting at say 100 Hz and descending you'd hear the sealed, then both, then the ported. When both played it'd be louder than one or the other working at their extremes. Mas could say it better (albeit over my head) but that's how I believe it would work. 2 similar subs are much easier to calibrate than 2 dissimilar ones (and 1 sub is the easiest!).

[DrWho]

How big is the room? And how loud do you normally listen? What are you running for mains?

As far as the differences you hear between the sealed and ported

systems, how do you know that the "extra boom" you're hearing with the

ported subs isn't the result of the room or them simply playing lower

frequencies? Sealed systems are often described as sounding "tight and

punchy" simply becauase they lack low frequency extension. Combine a

sealed sub with another sub that can play lower and you're not going to

have that punch anymore.

Also, the listening room is going to have a huge influence on the bass.

Often times people think a ported system sounds boomy because they dig

lower and end up triggering some room modes that the sealed system

doesn't.

Anyways, if you're looking for some real tight and deep bass, then you

might want to take a look at the new RT-12d. Subs with passive

radiators are going to have so much less distortion than those with

ports.

[bigpants_ku]

Dr. Who-
Thanks for this good advice. You've got a good point about the room
playing a big role, and the punchiness of the sealed high end subs
(velo and Martin Logan) I was listening to certainly would sound
different in my HT I'm sure.

To answer your questions, my current mains are RF-5, but I'm
building a new HT now and after it's done (hopefully will be done with
the basement and HT by September) I may upgrade those to RF-83 or
heritage stuff, just will depend on how it sounds. The room (when
it's done) will be roughly 17 x 40 but it's an odd shape and has other
stuff going on (a bar, a fireplace, poker table, pinball machine,
etc.) See the floorplan. I gave you one measurement to go
by- I dont' have a digital version of the plan with measurements on it
at the moment.

I did listen to a RT-12d, but the dude at the
store was having issues with it on his switcher or something, and it
seemed to be in and out, so I'm not sure it was a good audition.
I could probably do dual KW-120THX's in this room, but I can't find a
store that has any to listen to.

Take a look at the floor plan
and tell me what you think I should do. You'll notice that the HT
opens up one one side and the room goes forever (and that's why I'm
concerned- I'm afraid the room will eat up all my bass!

[bigpants_ku]

Oops! Here's the floorplan.

[DrWho]

That room behind the TV is for storage? How big is it? You could fit a killer horn loaded sub back there, or if you were feeling lazy you could bust out some insane Infinite Baffle subwoofage.

Your floor plan is rather open so I wouldn't expect much bass gains from the room at all....which means you're going to need a crazy potent setup to fill the room.

Are you familiar with the Danley DTS-20?

http://www.danleysoundlabs.com/DANLEY_dts20.htm

I think they go for around $4k, including an external QSC amp. I would probably recommend two of them for your room []

Though....how loud do you listen?

[bigpants_ku]

DrWho,

Again, thanks for your insight. Looks like the
Danley DTS-20 would be perfect, but WAF on that is nil. I can do
something like that in my next house when we have a dedicated HT room
and can hide stuff like the Danley. This new house is a spec
house and I'm making the best out of the unfinished basement before I
go to work September 1. That's the other problem- no income until
then, unless we sell our last house, which is not looking good, because
the real estate market in the town we moved from is dead.

Anyway,
that doesn't mean I can't figure something out. I'm not sure I
can put the sub in the back wall/room for reasons you'll see below
(although I'd love to if possible), so I'm likely going to have to go
to a freestanding in-the-room unit, I can spend some time on the forums
trying to figure out what would be optimal for my scenario, while I
continue construction. (The center channel had to be upgraded
ahead of time, since it's built in. I bought an RC-64 for that-
got a killer deal on a floor model ($299).

Ok, so on to the
HT: The room behind the media wall is indeed a storage closet,
but to me, it's more than that. First, it's a walk-behind media
wall access. Second, it's a bit of a hidden room (the access is through
a bookshelf/door with a well-hidden latch.) I guess now it's not
such a secret...Oh well. Lets hope our local robbers aren't
Klipsch forum readers. Third, it's a storage room.

The room
is 6 feet deep. Yes, it technically could hold some major
woofage, but probably not with the way I'm laying out the wall (which
is half bookshelves) as you can see by looking at the following plans
and progress pictures (just framed that wall yesterday).

The
bookshelf on the left is also a door, obviously. The distance
from the outside walls to the outside of the bookcases is roughly 18 or
19 inches (behind the sconces). This is the only place in that
room where I can see easily putting subs, as the space below the TV is
for electronics.. The mains will be setting free in front of
those wall segments under the sconces. But I don't know what kind of woofage I
could put in that space, and if I could, where it would go (behind the
speakers? Above them on a shelf?) and would I need to open the
walls and put in some kind of screen?

To help you help me (which
again, is GREATLY appreciated), I've done some math. The entire
room is close to 941 square feet, and 8,000 cubic feet. I know
that to get some good bass in there for movies, I'm going to need to go
big, but the budget is at least temporarily tight and WAF low. I
can see dropping maybe 4-6k on subs by this fall. Unless you can
see a way to do something else, I can only imagine getting one or two
floorstanding units that are not monoliths like the Danley. For
instance, would the Velodyne DD 1812 SE work for this room? Would
two of something else be more appropriate?

To answer your volume question, this setup will mainly be used
to watch movies. We watch movies pretty loud- at least theater
loud. I'll run some wire upstairs and run an old set of KSB 2.1s
on the B speakers. I do listen to music quite often on the main
system too, but in general the quality is more important to me than the
volume for music.

Here is another picture of the room's progress from the end of the stairs to give you a visual picture of the room's size:

What do you think?

[DrWho]

Could you provide a floorplan sketch? It looks like the room is going to be assymetrical? Just wanna run some numbers.

Btw, the Danley DTS-20 was designed to fit inbetween studs. That

doesn't seem to be an option along the front of your entertainment

center, but would it be possible to mount it in the ceiling between

rafters? I dunno if the dimensions work out or not, but that would be

something to consider. You only need an opening in the wall the size of

that small mouth at the bottom, over which you can put any type of

grill cloth. It also looks like you've got a big beam going across the

front? You could probably tuck them up behind that so nobody would see

them.

Is it safe to assume that you're going with RF-83's for the mains?

(since you've got the RC-64 center). I ask because I hope you realize

how deep the cabinets are...you would be hardpressed to fit a subwoofer

behind them without putting the mains into the middle of the room. And

you've also gotta account for proper toe-in as well.

It is possible to do an IB arrangement with your closet room thing, but

it would involve driving all the sound through a slot opening along the

sides of your equipment rack. It would require extra work to keep it

resonant free and you'll be introducing the venturri effect, which will

sound like "horn throat distortion" (the characteristic sound that many

people hate about crappy horns).

Actually...I was just thinking...you could probably do an IB over the

top of your entertainment center - firing through the rafters. You

could easily fit 4 to 8 drivers up there and let the rear wave firing

back down the space between the rafters and into the back room.

The single Velodyne DD1812 is not going to play any louder than the

Klipsch Ultra2 system. Two of the DD1812's might be sufficient, but

even that's pushing it. These systems were designed with 3,000 cu ft in

mind - not 8,000. Doubling up only gets you to 6,000 so really you

should be trippling up. Yikes! []

I really think DIY is going to be your best option, but that's going to

involve a lot more learning on your part. Unless of course you wanna find someone to design it for you. []

[bigpants_ku]

Yes, the room is assymetrical as all getout. I don't have an

"official" floorplan, but here is a sketch with rough dimensions (in

feet). Most of the ceilings will be acoustic drop ceiling at 8.5

feet (except for where I've got vents boxed in). I know, I know,

that might rattle- I'll weigh 'em down or whatever I have to do, but I

don't want to drywall the whole thing, and I want ceiling access.

I demo'd some subs and speakers last week, and the place I was at had

acoustic drop ceilings, and I never heard a rattle.

To start with, I don't think I am going to have time to learn how to

make a DIY SW or learn IB and build something appropriate for this

room. I would love to, but I'm starting a new job on September

1st and I'm going to be working a LOT. With the time-intensity of

my job, finishing my basement, and our new 12 week old baby, I just

don't see picking up a new hobby the likes of DIY subs and doing it

right. The upside of all that work, is that I'm going to make

some money, so I could afford a Danley DTS-20. That said, my

saying we can afford it, and my wife saying I can buy it are two

different things.

What do people charge to build DIY for someone else? Is such an option cost-effective?

So anyway, let's assume that we decide a DTS-20 is the tool for the

job, and I get WAF for it sometime this fall. Now we have to

decide where to put it. Look at that floorplan- I could possibly

put it vertically with the output on the floor behind one of the wall

sconces, but if I do, it will be behind a main speaker. But what

about the furnace and water heater room? I could put it in there,

right in the corner between 2 studs, spewing bass out of a hole in the

top or the bottom or the wall, whichever the experts recommend.

Would that be too far from the listening area or anything? (See

the layout of the listening area on a previous post in this thread).

Thanks again for your ongoing advice!

-Vance

[michael hurd]

Anyone have any input or advice on this sub? http://www.edesignaudio.com/edv2/product_info.php?products_id=606 Dual 18" with lots of power in a big vented box. Sounds like a recipe for a decent sub.

435 pounds, might be a little expensive to ship though. FOB Iowa.

[bigpants_ku]

Man that looks solid. The company SHIPS ALL 435 POUNDS OF IT FOR FREE to the US 48! (Sorry, Canada!)

I read the reviews on the eD website. Looks like the huge pros of

this sub are quality (big, low, quality output) and value ($2K).

The cons are pretty obvious, it's huge (26x26x49) and ugly (covered in

a skin not unlike a spray-on pickup bedliner), and can't be stashed.

If it weren't for the price difference, I'd say these cons are too big

to disuade me from a Danley DTS-20, but the price is crazy. I

just don't know where I'd put this beast...Maybe I could turn it into a

sofa table...