DIY subs - coming from dts-10 - 3k+ budget - Page 2

Make SURE the drivers are wired electrically out of polarity. That is the + of dts1 to the - of dts2 (and of course the opposite wiring on the other terminals).

This will put them physically IN polarity (due to the opposite mounting).

When you put a battery on the speaker cable both driver should move in the same PHYSICAL direction. One will more INTO the basket and the other will more OUT OF the basket. But they both will move INTO the same part of the horn.

That's the best description we've had yet for a topic that has confused many, many people. Thanks Ivan.

Curious to hear some impressions with the new driver in.

You probably shouldn't be clipping. I've not clipped mine and have run mine very loud. How do you have it wired to your ep4000?

When I had a single DTS, my EP4000 was in bridged mode and it clipped a few times. When I added the second DTS10, I changed to parallel and haven't had the first hiccup out of the amp! I'd experiment with that.

Do you still have your room bare concrete? If so, I would wait until you get all of the walls and sheetrock up. That may give you a world of difference.

Try an Orbit Shifter from JTR

http://jtrspeakers.com/home-audio/orbit-shifter-lf/

^^^^
I had one of these bad boys in my room; and yes sir, output above 20hz to impress.

Here is one, the Cinema F-20, and if you can handle the size two of these should be quite effective above 20 Hz. Two of them would cost you around $300 to build...however, they are visually more imposing and require more space than many subs (DTS-10 included). One last point, if you desire output below 20 HZ, you should look elsewhere.

If you want just 20hz and above just build a THT for cheap.

There are a few people who use this JBL pro-cinema sub. It has tremendous output > 25 hz. Room gain in a small room (domestic) would probably get down to 20 hz. Haven't heard it myself but its an inexpensive plain & simple brute. Two would be fantastic for just over 3 grand brand new. The driver itself is used in the latest Synthesis system (subwoofer) which costs quite a bit more.
TH221 could solve your dilemma.

Sorry this is the JBL unit: JBL 4645C
http://www.jblpro.com/pub/cinema/4645c.pdf

Are you sure your DTS-10 is in a good location? Before doing anything, you should place the DTS-10 in your listening position. Move your chair into another room, temporarily. Then walk around the room with an SPL meter to check sound pressure in different room locations and compare them with the output in the position you've had the DTS-10 at. You might be locating it in a room null.

If it's in a bad spot, then no subwoofer on earth will make you happy in the same position.


EricH still has two of the 2245 subs available, which is supposedly higher output and better sounding than the 2242 in the 4645c? Apparently, either would use a much smaller cabinet (10cu.ft.)

EricH's 2245's:
http://www.diysoundgroup.com/JBL_Group_Buy.htm

Subwoofer for hi-fi: 2242H vs 2245H
http://www.audioheritage.org/vbullet...245H.&p=227138


So, I thought the DTS-10 was comparable in output to the THT from 20-80hz. Am I wrong?

I wonder if Eddie is on to something. I've never had a sub before that was as sensative to all the variables. And there has been major performance swings in my room. When dialed in at its best, I don't feel a need for supporting subs like you mention. But there were times with the wrong EQ, position, or room treatment that I felt that way.

If you are keeping the DTS-10 in the system don't mix subs, build more DIY DTS-10's

Up your crossover on the avr and have a listen

The F-20 is a pretty similar design to the THT, and I have high-SPL measurements here. Based on the rising response I saw in the 1W measurements of a THT I posted here, the THT will have an edge on the F-20 above 40 Hz.

DTS-10 measurements here. The DTS-10 numbers were collected at 2M, so they are 6 dB lower than the 1M values (distance is doubled).

You really do need a highpass. Especially if your room is open to other areas and you only have the one DTS-10 to fill it.

I'd want it to start rolling off somewhere around 15Hz or so in your situation. 48dB/octave. Especially if you're a bass nut like me and you're pushing it to its limits often. I use a Reckhorn B-2 on my own tapped horn, but it can be tricky to get set up properly unless you loop it through a computer running REW while dialing it in.

The thing about a horn is, if it's run too hard below the corner you start getting into distortion land. The horn starts amplifying the harmonics, more than the fundamental. With no highpass, this could very well be what you're hearing when it sounds like it's clipping.

A horn for a 21" driver will dwarf the DTS-10. Especially if you load the driver properly (20 Hz +/- for the Fc).

With an EP4K, you are quite capable of overdriving the sub, and it is distorting/clipping/complaining as a result. Are your clip lights flickering? If not, the sub has reached mechanical limits. Highpass will help a lot. As OW said, horns do not play nice below Fc.

As others have said, placement will make or break any sub. The best sub in the worst spot will sound awful. The worst sub in the best spot will sound better, but placement alone does not work miracles....

For Highpass/EQ? I like the MiniDSP, but it is a little fiddly to set up. Simple highpass? The Mic2200 will do that, but to be honest - it costs nearly the same as the MiniDSP and does far less of what matters.

A word of warning - unless you plan to measure each tweak on the B-2 with REW, avoid using the EQ part of it altogether. Just bottom out the subsonic knob with no EQ boost and see if that improves things for you.

The reason I say that is the B-2 does some odd things with the highpass once you start dialing up the EQ boost on it. You can actually get it to move the highpass down to the point it'll still be like you still have no highpass.

No EQ boost however, and the 10Hz subsonic setting on it should put you in the ballpark of where you want to be. If still not satisfied, raise it a bit and see if it helps any.

There's two parts to overdriving, thermal limits and excursion limits. It sounds like you're exploring the excursion limits. A highpass will help a lot. That's typically a good sign that you need more (or more capable) drivers to get the SPL you want. Bass takes displacement, and though they're burly, the 12s in the DTS-10 do have their limits.

Have a look at this, which is arguably the most complicated tapped horn fold out there in the wild, and we're not done with it yet. It is certainly the most complicated fold I've drawn up. This uses a pair of 15s, and it is HUGE. It also puts a few dB on the DTS-10, as would be expected. Did I mention it is HUGE?

Most of the 21s I've modeled don't go as low as the DTS-10, but they do get louder. They're gonna be in the 25 to 30 cubic-foot range as far as cabinet volume, which is beyond cumbersome for a sub that does not go much below 20 Hz.

Personally, I like the idea of multiple smaller cabinets, cause I gotta move them. Since I'm getting older, 20 cubic feet is pushing things.....

Consider - a single 15" driver in an 18-cubic-foot cabinet models at 123 dB at 20 Hz 2pi using a $250 (street price) car stereo driver. A pair model at nearly 130 dB, 2pi. Four? Assuming you had enough power to drive them (and you do...) they should exceed 130 dB in a 2pi setting at a meter. In a room? Over 130 at the couch, easily. If this is not enough, seriously, seek professional help.

If you want to get below 20 Hz, the same drivers can dig a little deeper (-3dB at 14 Hz), but give up ~5 dB of output capacity and require 12 more cubic feet of cabinet volume. Nothing ever comes for free.

Mike, since the tapped horn design utilizes both the front and rear energy of the drivers, is it fair to say that the displacement is doubled? In other words, the two 12" drivers in the DTS10 act similar to the displacement of four?