My First Sub

[---k---]

All,
Long time AVSer, and have been lurking here for a while now. You have really inspired me to build my own sub. I think that I'm up to the challange of building my own box, and understand the rule that there is never enough bracing. So, I was hoping that I could get some help with the design. My thoughts so far:

1) Goal: As much SPL power as possible in a single box sub. I'm thinking a 15", or possible dual 12" or 15". No one is currently shipping an 18", correct? Obviously, I want it to sound good, but I think I would be willing to trade a little SQ for more SPL. If I were to purcase a sub, it would likly be a SVS PB12+ or if $$ wasn't an issue a PB12+/2. So those are my targets. My room is approximately 18'x18', with a one open door way. Tubes and IB is NOT options. It will just be painted black.

2) Extension: I would like extension down to 20hz. This will be used for a lot of Home Theater. More and more rumble is down low. I will have a BFD, to help out with this. I don't think I will have the budget to use a linkwitz transform, but would consider.

3) Size: I like the end table size subs. My current sub is 13x15x21" and looks a little small in the corner. The top of the arm of the sofa is 25", so I could go up to around 2'x2'x2' (8cuft). Something rectangular would probably be better though.

4) Ported/Sealed: I'm not really sure on this one. I like the idea of the sealed, because it is easier. I'm willing to go the ported route, but we will need a long discussion on how to test/tune it.

5) Amp and EQ: A BFD is on my christmas list and will b purchased no matter what. I'm thinking then either a Behringer EP1500 or Nady XA-900. I think this is the most economical/flexible. But, I wonder if some of the plate amps, that have the built in low boost, would be a better route to follow to achieve my extension goals.

6) Budget: ~$600 - $800.

7) Lifespan: I would like this to be the last sub I own for a while.

8.) Timing: I would like to be building over the Christmas/New Years holliday. So, the driver and amp will likely need to be ordered soon. I would like to wait until the new Ascendant drivers are shipping, but it seems like I could be waiting forever.

I've downloaded WinISD and Unibox and have tried to model a few boxes based on the Titanic and Soundsplinter RL-P15. But am stubling along, and not sure if I'm doing it right. I've seen the RL-P15 recommended a few times, but WinISD has very differnt parameters in it than what I see on the Soundsplinter website, and I'm not sure whether I should be modeling with the 2ohm or 4 ohm specs.

So, if you guys could walk me though this adventure, I would be very grateful. I really want to learn the ins and outs too, so please don't hesitate to go into technical details and explanations, or tell me to go read something.

thanks,

[ThomasW]

Box size is the determining factor in deciding between sealed and ported.
If you need a really small box, the only valid option IMO is sealed. Yes I know there are PR's, but I've never been able to get one that sounded good, and I've been building subs for a really long time....

Correct no one is shipping 18"s, and at this point Adire and Ascendant aren't shipping much of anything.

I'm not a fan of WinISD. If you can't use Unibox then try WinISD Pro.

So give us the biggest box size you can live with and we'll go from there...

[Brian Bunge]

Thomas,

First things first. He lives in Naperville, Il, so that means he should first send you and me a pizza from Lou Malnati's! I love that pizza!

[---k---]

Thomas,

I think the 2'x2'x2' box is roughly the max size that I want to be. This is a lot larger than all of the sealed box recommendations that I've seen. I think that I like the more punchy bass sound of a sealed sub.

Adire isn't shipping either? I've attempted to model a few boxes using the Tempest. That is dissapointing that no one is shipping anything right now. Not to get to far off topic, but would it wise to wait to build my sub? I want to do this during the winter, but am willing to wait if the reward is expected to be great.

When I said WinISD, I ment WinISD Pro. I have Unibox on my work laptop. I don't have Excel installed on my current computer and can't seem to find the CD. Will fix that one of these days.

As far as the pizza goes, Lou's is tasty, but I much prefer Uno's downtown (the chains are crap!)Lou learned how to make pizza while working at Uno's, so it is very similar. I think I could be talked into sending Thomas a pizza after were done with this.

[ThomasW]

That's pretty small comparatively speaking.....

There wouldn't be enough room for a port in a 2" cube. Tuning most of these drivers to ~18Hz means about a 28-30" long port

Can you live with drivers on opposite sides of the box? If so, a pair of the 15" TC2+ firing in opposition would be a pretty sweet sub. This would play loud and wouldn't walk around like a single high output front firing driver.

The best bet would be to go sealed (nothing to calculate there). Then use a Linkwitz Transform circuit the boost the low end performance. (If you scratch build it, LT circuits are pretty cheap.)

Note that depending on room gain and the BFD you might get enough output at 20Hz without the LT circuit. I'm experimenting with some filter settings for the BFD that potentially could 'fake' some aspects of an LT circuit. But that's tricky to do without the benefit of a real shelving filter.

This is my 'quasi' shelving filter using the BFD

Image not available

[cinema bob]

if extention and volume are the top considerations then you might want to look into the horn loudspeakers from bill fitzmaurice. the tuba24 sounds like it would be right up your alley. they will shake you to the bone, they are cheap and they sound pretty darn good. IIRC the tuba24 uses a eminance hl10a driver but i'm not positive.

http://www.billfitzmaurice.com

[ThomasW]

This is a Tuba24 LMS plot, not a computer sim.

[---k---]

Thomas,
I've seen photos of Steve's Tubzilla and a few others, so yes 2'x2'x2 is small, realitively speaking. My 2'x2'x2' sub dimension limits are rough. I can probably be talked into an inch or two more in a direction. I showed my wife a photo of the SVS PB12Ultra next to a sofa, and she said that was acceptable, and I agree with her. They are a good balance between big and reasonable.

I don't see why I can't use a pair of 15" drivers on opposite sides of the box. What would be the limiting factors? Here is a photo of the corner where the sub will likely be located. You can see how small my 13"x15"x21" sub looks there. If I front fired the sub, it would be firing into the sofa. I figured I would fire it to the right, to the open area. To the left, is my homemade bass trap, with 4" of OC703 and 8" of R30. Would it be a problem to fire into the sofa or the bass trap?

I'm liking the idea of dual 15" . Sounds powerfull. hehehehe

As far as room gain goes, I don't think that I have much down low. I moved my sub all over the place and used ETF one day. See these results My current sub really isn't rated to go low, and you can see that it falls like a rock at ~30hz. So, I think I'll probably be using the BFD and can build a linkwitz. Getting a bread board and building one shouldn't be a problem. I have done any real sodering and stuff since I was probably 12 years old fixing my commodore 64 joysitcks and playing with a science kit, but think I could figure it out. This is something that can likely be built afterwards and added if needed, right?

[ThomasW]

Sorry but opposite firing 15"s won't work in a corner.

Any sub should be pointed away from the furniture toward the open area of the room. (or pointed straight up)

For that location I'd go with the SS RL-p 15", a sealed box as big as will fit the location.

Start with the BFD, if you need/want more low end then build the custom LT. Yes they are simple enough to be built on a breadboard.

Here's a link to John Murphy's LT page

[---k---]

Awe, you were getting me excited about dual 15" drivers.

What about one firing down and one firing forward? Or, if I put a base plate on top (to protect the driver) and bottom, and fire one down and one up, it could look pretty cool. If my math is correct, the TC2+ can barely be downward fired, and the RL-P15 has no problems being downward fired. Correct?

I need to do the models to see why you recommend the TC2+ for 2 drivers, but the RL-P15 for a single. They have very differnt Fs and Vas. I think the lower Fs and higher Vas of the TC2+ is better, but I must be missing something.
To do the modeling in Unibox, it wants Sd inputted, but that isn't given. How do I calculate this? Or what is the minimum parameters I need to put into Unibox to make it work.

Thanks for your assistance. It is really appreciated. I'll read up on the John Murphy's LT.

[edit for a little grammer]

[Bent]

I'd imagine the increased Xmax of the RL-p 15 and the increased power handling are the deal makers over the TC2+

Also note the RL-p (big brother to the TC2+, a TC9 with some OEM mods for Sound Splinter) also utilizes dual spiders to help keep the voice coil former centered during higher excursion and a real NBR (natural butyl rubber?) surround.

I personally wouldn't recomend different orientations for two drivers, as that would affect their parameters in different ways - making them seem like two very different drivers in one enclosure - how much is open for debate, as I can't prove it, but it's what my common sense would tell me.

I'm quite sure that the Sd for the 15" TC2+ and for the 15" RL-p would be the same, as they share the same spun aluminum cone.

[ThomasW]

Both the SS RL-p drivers, and all the Oaudio TC2+ drivers have butyl surrounds.

If drivers are mounted like those in Tube-Zilla (one facing up, the other facing down) there is some (minimal) effect on one-way Xmax. Other than that, orientation has no impact on T/S parameters

[---k---]

I did some modeling with Unibox this afternoon, to get a feel for things. Does this look right, and is this the best way to post this?:



I think that I could be very happy with the one or two TC2+ drivers with the filtering provided by the PE Ext. Amp (but I would use a BFD). It looks like I should be able to get it down flat to 24Hz. Hopefully with a little room gain, it can be even flatter.

I guess I need to decide if I really NEED 2 drivers. 110db seems like a lot of power, but the room is roughly 3000cu ft, so.... Thoughts?

[ThomasW]

Thoughts?

A finished 2' cube isn't going to have 226L internal volume. The walls need to be 1.5" thick. The driver and bracing will also displace some internal volume.

You can't use a pair of 15" drivers in a 2" cube unless you can move the sub out into the room.

You can't port a 2" cube down to 18Hz, unless you want the port sticking out like a stove pipe.

The room is pretty big, that means you need a high output driver and a BIG amp not a plate amp. This means the SS PL-p15" driven by a pro-sound amp.

[---k---]

Sorry but opposite firing 15"s won't work in a corner.

Any sub should be pointed away from the furniture toward the open area of the room. (or pointed straight up)

I wasn't aware of that. I thought that the bass was low enough it would easily pass through a sofa. If a sub is downfiring, does it matter if it is next to a sofa?

A finished 2' cube isn't going to have 226L internal volume. The walls need to be 1.5" thick. The driver and bracing will also displace some internal volume.

Yeah, I thought about that. I had the tape measure out a second ago, trying to figure out how big I can make it. I was thinking I would make it a downfiring sub, and that takes away a few inches. I'm starting to think that 2x2x2 exterior dimensions may not be possible.

My corner bass trap takes up too much room! Of course, if I put a big sub in front of it, covering it up, it isn't doing much. If I want to use that corner to hide the sub and have a really big sub, I may have to shorten the bass trap and put it on top of the sub.

If I go a single 15" driver, I can make the box smaller. When I was playing with Unibox, it seemed that once I turned on the External Filter function, the size of the box really wasn't as important, and I didn't need that big of a box.

The room is pretty big, that means you need a high output driver and a BIG amp not a plate amp. This means the SS PL-p15" driven by a pro-sound amp.

I was always planning on a BFD and a Behringer EP-15000. I was just using the PE Amp Filter, because the button was there. I assume the BFD would be capable of doing the same thing. Correct?

The TC2+ seems to model flatter to me, has more spl at low freq, and the same amount of SPL elsewhere. Did I do something wrong? Can you expain why you prefer the SS PL-p15?

[ThomasW]

I wasn't aware of that. I thought that the bass was low enough it would easily pass through a sofa. If a sub is downfiring, does it matter if it is next to a sofa?

The sofa is a bass trap.

There are 2 options for that corner, driver pointing up, or driver pointed out into the room.

The RL-p 15" won't model as flat, but it can handle more power and has greater Xmax. You're going to to need those characteristics since the box is going to be small.

Set the bass trap on the top of the sub. It's actually not really deep enough to absorb much low bass. My corner traps have a 24" radius

[---k---]

Well, plans are changing.

I tried to mock up a couple of differnt box sizes to see how they would work in that corner, and it just wasn't working. The wife wasn't happy with significantly bigger boxes, and I was't really either.

Anyway, I had my current sub sitting next to the TV.See this fuzzy photo. And I thought it looked good. To my shock, my wife agreed and went so far as to agree to a pair a twins before I asked. So now, I've got lots of questions:

The new plan is to build a pair of subs, similar in size as my current one, which is 13" wide, 15" deep, and 21" tall. I can probably bump those diminsions up a bit. 18" wide x 26" tall x 20" deep (100 L?) is probably my new max. (This is bigger than the 3cu ft PE box that you recommend a lot, so I assume it is good.) I would actually prefer a little slimmer.

Question, what is the most narrow box I can make and still fit a 15" driver in the front? I could probably side fire it also, which would eliminate this problem; will this introduce any other problems? Is the RL-p15 still the recommended driver for a 100L box?

I've consider moving down to a 12" driver. It seems like a 100L box results in a Qtc less than 0.5 with either the SS RL-P12 or the TC2+ 12. I thought I read that this isn't good. What would be the best volume for a sealed 12" sub, that would give max extension. Would I still want to use a SS RL-p12? They are $150 more than 2-TC2+ 12", is it worth it? 2 of the RL-p15 is only $84 more than the TC2+. The TC2+ 12" is definitely nicer to the budget.

How much deep extension would loose by choosing a 12" over a 15"? I'm thinking that with the right EQ or linkwitx transformer, they could both provide the same extension, but the 15" would have mre SPL. Correct?

Also, are the specs on SoundSplinters website for the RL-p12 correct? It has a lower Fs than the 15" and has the same Xmax, this doesn't seem correct.

I'm sorry I'm asking so many questions. I'll definitely ship you the pizza when were done with this. If you want, you can just point me in the right direction for some of these.

The BFD is ordered, and will order the amp and driver as soon as we get there. Thanks for your help.

[ThomasW]

Here's my recommendation.....

Make two cabinets and use them as stands for the mains.

If you use 12" drivers the cabs can be 13"-14" wide.

The other issue is that none of the high quality sub drivers are shielded. Were you to mount the driver low in the cab then there probably won't be interference issues with the TV.

The Oaudio 12" TC2+ would be a good choice for this use

They lower the Fs of any driver by adding mass to the cone.

[---k---]

Thomas,
Thanks for that idea. I have seen other people do that, but I hadn't thought of it for myself. Doh!

If I'm still holding on to the idea of a 15" driver, can I get away with a box 16x24x20 external, which I think would give like 3 cu ft internal. Or do I need to go up to 18x24x22, which should give me almost 4 cu ft.

[ThomasW]

You can certainly use 15"s, however the reality is that you have pretty small main speakers.

What's the point having tons of low bass output that isn't going be used, after you set the relative output levels?

Now if the goal is to 'future-proof', so you have greater low bass output potential when you upgrade to a MTM or similar large speaker, then sure go with the 15"s

[---k---]

Oh, forgot to mention that I have a pair of Ascend 340SE on order. They will be here in mid January. I plan to audition them against a few other speakers, but I have a feeling that the Ascends will stay.

Is there any effect on the sound of the Ascend, when you place it on top of a big, wide sub? I've seen photos of other people doing it with much more expensive speakers, so I want to assume it doesn't, but people also buy Bose.

[ThomasW]

The woofer magnets won't have a significant impact on any speaker sitting on them. The only possible issue is with the TV.

You should take the height of the tweeter into consideration, when designing the sub boxes. Keep the tweeter at ear level.

[---k---]

The stands that Ascends sells are 24" high, and I'm told that puts the tweeter at 34.5" high. So that is where I was going to start. Maybe an inch or two higher -- I'm a tall guy.

I think my question was more about the radiating patterns of the speakers. I have attempted to read some of the speaker design theory threads, but am over my head at the moment. It seems like some focus is placed on positioning of the tweeter with respect to the woofer, so I wasn't sure if I put my speaker ontop of the sub, how it would affect it. Also, I wasn't sure if having a big, flat mass under the speakers would affect the sound radiation patterns. If I'm not making sense, it is because I haven't spent enough time reading those threads yet, and you can tell me to go back to my corner and shut up.

[Dennis H]

The subs won't bother the mains as long as the main's front baffle is even with or in front of the sub's front baffle. You just don't want it behind so the tweeter can reflect off the top of the sub. For the same reason, you want the mains slightly ahead of the TV -- no reflections off the side of the TV. As Thomas said, sit in your chair and measure the height to your ears. That's how high the tweeter should be. Ascend doesn't know how tall you or your chair are so their stands are just a guess.

Edit: however, you'd better test your TV with a sub driver before you go ahead. If it's a CRT, it may not like having a big magnet that close.

[---k---]

Thanks Dennis.

Well, if I use the subs as stands, I would put them where the speakers are now. They would be almost 2 feet to either side, and then there is the vertical direction. I plan to get a big DLP someday, so they may end up a little closer, but not much. How far away do I need to keep these things from a CRT? I'm shocked that 1" of MDF doesn't shield the driver pretty well.

[ThomasW]

1" of MDF doesn't shield much in the way of magnetic fields. And neither does 1.5" which I suggest you use...

The necessary distance will depend in the level of shielding in the CRT.

You can always add 16 gauge sheet metal to the inside of the sub box when building it. Gluing on a couple low cost bucking magnets doesn't hurt either. These things usually solve most problems.

[---k---]

Thomas,

1.5" MDF??? I was just re-reading Adam's 18" Av thread and noticed the discussion of weight this time. Wow! It had never occured to me how much these things weigh. But, I fully trust you and will likely do 1.5".

Both the TC2+ and RL-p15 appear to be rated at around 400W. So, it looks like I need at minimum a Behringer EP-1500 to drive two of them, correct? Are there any more cost effecient amps out there? The Nady XA-900 is only rated at 300Wx2 @ 4ohm, so I don't think I can use it and get full performance, but it would be nice to save $100

[MDJones]

I am currently running a Behringer EP1500 with a single Rl-p15 (DVC4) in bridged mono. I believe it's something like 800 watts average (900 W @ 1kHz) - these things can handle some power. Mike at Sound Splinter had his Rl-p15 running off a Behringer EP2500 single channel with a 2 ohm load (1200 watts 8O ). Using 2 subs, there are numerous ways to wire them into a 2 channel pro sound amp. Here is a nice site from crutchfield with wiring options. You could probably get away just fine with the EP1500. Also, I don't know that you will find much more bang for buck than with the Behringers.

[ThomasW]

Subs tend to "walk" at high SPL, the weight and using carpet spikes helps keep them in place

If you want to save a little weight at increased expense, use a layer of 3/4" Baltic Birch ply ($50+/sheet) inside a layer of 3/4" MDF.

We use MDF as the outer layer because it machines nicely (no tendency for tearout).

This is the best price I've found for the EP1500. I know nothing about the seller.

http://stores.ebay.com/Pro-Audio-4-Less_W0QQssPageNameZviQ3asibQ3astoreviewQQtZkm

[---k---]

I'm going to take your silence about other amps to imply that the EP-1500 is my best bet. PE has them for a few $$ more and free shipping. PE seems to be having a problem with their website right now, so I'll order the it tonight.

Then it will be down to the drivers. I need to mock up the size with some card board boxes and decide between 15" or 12" drivers. Then I'll have to decide if the RL-p is worth the extra $$ over the TC2+.

[PoorboyMike]

This place has the Nady XA-1100 for $146 shipped.

http://www.digitallyunique.com/xa-1100.html

They are out of stock right now but a guy on the IB forum got Musiciansfriend to pricematch and they have them in stock. Just another option for you to consider, as if you don't have enough already. :B

[---k---]

Wow, that looks like a steal. Am I reading the specs correctly, that the Nady does 2x475@4ohm vs the EP-1500 which does 2x400@4ohm? The Nady spec for bridge mono looks a little wierd, since it is only 1100 vs. the Behringer 1400.

To save a $100, I'll look around and see what kind of prices I can get and if Musiciansfriend will price match. But, is the Nady generally considered eqaul to the EP-1500. I know for the most part Watts is Watts. But is there any downside to getting the Nady?

[PoorboyMike]

Wow, that looks like a steal. Am I reading the specs correctly, that the Nady does 2x475@4ohm vs the EP-1500 which does 2x400@4ohm? The Nady spec for bridge mono looks a little wierd, since it is only 1100 vs. the Behringer 1400.

To save a $100, I'll look around and see what kind of prices I can get and if Musiciansfriend will price match. But, is the Nady generally considered eqaul to the EP-1500. I know for the most part Watts is Watts. But is there any downside to getting the Nady?

I couldn't tell you; I haven't fired mine up yet. I can tell you this though, the thing is built like tank. It weighs over 40 lbs and appears to be made well. The fans are kind of loud though, (ok, so I have fired it up, I just haven't hooked it to anything!) but it doesn't cost much to quiet them down. The Behringers would probably be just as loud and require mods also if they will be in your listening room.

[ThomasW]

The Nady won't drive 2 ohm loads and has VERY noisey fans (easily replaced with quieter PC units).

The 1400 watt spec for the Behringer is for a single 2 ohm load

If you use the TC2+ then the Nady 900 should be fine. If you go with the RL-p 15"s get the Behringer. Or........

You can find the bigger Nady 1100 here...

http://www.amazon.com/gp/product/B0002D0RR6/104-6334842-3161547?v=glance&n=172282&v=glance

Or here with free shipping

http://www.avdeals.com/djequipment/XA1100.htm

[---k---]

I was leaning towards the Behringer until Thomas appeared to approve of the Nady XA-1100 by posting a link to it. So,I got my credit card out and called Musiciansfriend to get them to price match the Nady XA-1100 price, and they wouldn't do it. They said that guy isn't an authorized dealer, and that the cost was WAY below theirs. $199 w/ free shipping was the best they could do. I think that I'm going to order it tonight.

[Edit: I didn't order it yet. I keep changing my mind. The Behringer has a varible speed fan, so maybe it will be almost quiet enough without voiding my warrenty. And after I add $25 for two quiet fans, that cuts the price differance to $30. I think Behringer has a little better rep, no?

Yeah, I'm starting to get to that point where I don't want to learn and just do whatever Thomas says.
End Edit]

From the Nady $146 thread, I figured out that I would need 2 of these cables: http://www.musiciansfriend.com/srs7/...se_pid/333031/ to go from the receiver. To go from the BFD to the AMP, do I just want two of these:http://www.musiciansfriend.com/srs7/...361707/c_lv=1/ ?

Anything else I should order with the amp? I figured after I order the amp and drivers, I would post of list of terminals, spikes, and whatever from PE, and get you guys to sign off on it.

Thanks all.

[---k---]

Well, I ordered the Nady 1100 from Musciansfriend today. Now I need to order the drivers. It will put me slightly over my budget, but I am going to order 2 SS RL-p15.

Question, do I want the 4ohm version or the 2ohm version? And just for my education, why? I think I want the 4 ohm.

Thanks.

[SteveCallas]

Don't you think you are taking a bit of a risk assuming you will be happy with the 340s and building the subs to match up as stands at this point? As far as the size of the subs and getting them to fit in your room, the idea of putting the subs under your speakers is a great idea, but, if I recall, you aren't yet sure on what speakers you will end up with.

A 24"-26" tall sub will put a lot of bookshelves' tweeters at ear level, but if you are still auditioning, who's to say what you will end up with?

[---k---]

Steve,

Good to see you. I was hoping you would show up sooner or later.

You raise a good point, and one which I have had that thought about also. But, I was thinking 24"Hx18Wx?D before Thomas suggested using them as stands. I was just going to put them to the inside of the speakers. So, whether I use them as stands or not, I don't think it will change the sub woofer size. I also planned to put the 16ga steel between the MDF layers for shielding, to give me maximum placement flexibility, for whatever the future holds.

Of course, there is always the other problem: do you get stands that would put the the tweeter at ear height when sitting upright or fully reclined? Big swing.

I'm making some sketches right now, trying to decide what looks best. I'm really torn. With the Ascend dimensions, a sub box 14wx36h w/ a 12" driver looks real good. But I want a 15" hehehe

I'm just ordering the parts right now, and plan on doing all the cutting over the Christmas - new years holiday. So, I got time to change my mind. I still haven't ordered the drivers either. I like the price of the TC2+ and the lower Fs.

[ThomasW]

Buy the 2 ohm drivers and wire the individual VC in series to create a 4 ohm load. Run the amp in stereo with one sub/side

You don't need any special cables. You can run standard RCA cables between all the gear and simply use mono RCA to 1/4" connectors. Radio Shack or PE sells these

There's not point in running XLR cables anywhere, unless your receiver or pre/pro has a balanced sub output.

[---k---]

Thanks again. Can you explain a little bit more. Do you recommend the 2ohm, because of its lower Fs and higher Vas, or is there some benifit to using the 2ohm driver? Also, and maybe this is a dumb question, if I get the 2ohm and wire it for 4ohm, does that give it the specs of the 4ohm driver?

Using 1/4 cables makes things easier. I got the impression from somewhere that I needed to use the XLR inputs.

[ThomasW]

Sorry this is not a good day to ask for explainations....

Forget about the specs. The reason to buy the dual 2 ohm driver is so it can be wired to make a single 4 ohm load.

You can use 1/4" connectors if you want, just make sure they're mono (unbalanced) not stereo (balanced).

There's no reason to use XLRs. They're only needed if your receiver or pre-pro has balanced (XLR) outputs.

[SteveCallas]

Of course, there is always the other problem: do you get stands that would put the the tweeter at ear height when sitting upright or fully reclined? Big swing.

Well I'm 6' tall and I knew that I would be, at the very least, audtioning the 340s, so I built a pair of stands. The stands Ascend sells are 24" high. I took a bunch of measurements from the ground to my ears in a variety of sitting positions, and settled on 36" - so I made my stands 26". It worked out great while the 340s were here.

I realize that 36" figure may be worthless without giving you the height of my couch - I'm away from my apartment tonight, so my best advice is to measure from the ground to your ear in a variety of sitting positions and go with a number slightly higher than the average. Subtract 10" and you've got the ideal height for stands for the 340s. Hope that helps.

[---k---]

Sorry this is not a good day to ask for explainations....

Forget about the specs. The reason to buy the dual 2 ohm driver is so it can be wired to make a single 4 ohm load.

Been there. No problem.
Actually with what you said, it makes a little bit more sense.

2 RL-p15 have been ordered. I decided that 3 months from now, I didn't want to be wondering if it could have been bigger or better.

Curiously, Mike at SoundSplinter said:

You mention that these are home theater woofers, for which I would usually advocate a ported enclosure - however given that you will be running TWO of 'em, you shouldn't need it unless you really have a deaf wish! ;-)

For the flattest frequency response on the RL-p15 in a sealed enclosure, I would suggest 2.1 cu ft net internal volume (2.31 cu ft gross internal volume) per speaker. You could also add up to 3 lbs of polyfill to each enclosure depending upon your own personal taste. If you ultimately find that you want more output at low frequency, I would suggest constructing an enclosure at 3.0 - 3.5 cu ft net volume per speaker, tuned down around 20 - 22 Hz.

I told him that I was planning on something sealed around 3 cu ft. and use heavy fill, targeting a Q = 0.5. (I think that is what we are doing.) I asked if there was any reason this would be a bad idea.I haven't heard back yet.

[---k---]

Steve,
I'm 6'-3". I also came to the conclusion that 26" stands is about the right height for me and my furniture. It will also give the subwoofers the 2:1 aspect ratio I was looking for. Whether the end up being stands or not, I'm getting really excited. I should have the amp and drivers early next week.

[Edit, I'm a moron, it isn't a 2:1 aspect ratio. It is closer to 1.5:1. It looks right in my sketch, and thats all that matters!]

[Bent]

k, Mike knows what he's talking about - but he has a different opinion as to what is held to be true here, respectfully leave it at that.

My subwoofer works very well, and it isn't anywhere near as small as 3.5 cubic feet.
I probably have more than 3 ft^3 of mdf making up the enclosure.
It's outside volume is 11 ft^3.