Usher D2 "clone" Project gone OPEN BAFFLE!!!

[ChopsMX5]

How are you getting those numbers?? The woofers are 95db figure 98db for 2. If the one you got were 97 figure 100db in the lower midband.

Rob

Well, considering I had to drop the gains back on the woofers about -7dB from what they were with the 98dB sensitive Klipsch Cornwalls, and still add about another +4dB of gain to the horns to match up to the Usher woofers, they're quite a bit more efficient than 100dB.

And at that 110dB SPL I was talking about, that 14 watts was the peaks from bass drums that got up close to 114dB. When running at a constant 110dB, the amp was peaking around 3 watts rms.

Also, when I used to hit those kind of SPL with the Klipsch/Altec combo, the master volume on my receiver was around the -12dB mark. Now to reach that same SPL, the master volume is down at the -20dB mark.

So in short, I've knocked back the output gains on the xover for both the woofers and horns, and am reaching the same SPL's at lover volume settings.

That's how I'm coming up with the 104dB (or more) at 1W/1M. It kind of adds up that way. Besides, I have no earthly reason to make any of this up.

[ChopsMX5]

I've been at it again today, this time for several hours. I started completely from scratch, putting the xover and EQ settings to "zero" so to speak. I turned the horns off and just played with the xover settings on the Ushers only. Once I got them where I wanted them with the proper xover point, I turned them off and had a go with the horns. I did the same with them minus the xover point. Once I got their levels just right, I turned the Ushers back on and tweaked with the woofer delay settings until everything was blending as close to perfect as I could get them.

You know, I remember reading somewhere that if you use and adjust a crossover properly (xover point, levels, delay), it can have a similar effect as using a parametric EQ. After spending a couple hours alone simply adjusting the xover, I now see how this is completely possible! Without even touching the EQ, I was able to get a pretty decent flat response from 100Hz all the way up to 10kHz and completely eliminating that annoying peak around 1kHz I had before.

So back to tuning... Once I got everything sounding as good as possible with JUST the xover, I started work on the EQ. With about an hour of tweaking, the EQ itself looks totally different and civilized compared to before, as does the curve on the SynRTA graph.






And just a couple pics of the RTA setup...

[ChopsMX5]

I've got a couple updates. Not that anyone cares (which is apparently quite obvious).

1) I just ordered a Behringer DCX2496 digital xover which I will be using on the front three channels. At the same time, I ordered an AudioSource AMP100 which I will be using to bi-amp the center channel (one channel for the woofer, one channel for the horn).

2) I added some LED rope lights to the backs of the OB's and to the bottom of the couch and took a few night shots.

[Ian Mackenzie]

Good work Chops.

Looking back at earlier posts you now apear to be answering your own questions. This is often the case with DIY.

Ian

[tomee]

Nice project! I don't have the room to try an open baffle but it looks interesting. In theory the wider the OB the lower it will go, but maybe there is an optimum width that works with room gain, and going wider doesn't work well at all? You could experiment with adding 1 foot 'wings' onto either side of the baffle to make the OB work down into lower frequencies and see if you need less EQ boost.

I'd also add that with 4 of those woofers in that room it's no wonder you're not seeing any cone motion! Put them on an outdoor open stage and try to get 100 dB out at 100 feet away and watch the cones fly out of the baskets on the first low bass note! You're using an OB in a 'safe' location for sure.

Did you try the woofer in a ported box at all?

Funny thing is that before I came across this thread I was looking at those Usher 15's in the PartsExpress catalog and wondering what they would be like in a large format 2-way. Usher woofer with a 4" Selenium compression driver and one of the constant directivity horns all in a 5 cubic foot box. But in the end day dreaming is free but DIY isn't...

[clmrt]

Some nice tube amps will give you the same effect...

Oh - and,

[louped garouv]

I've got a couple updates. Not that anyone cares (which is apparently quite obvious).

I've been following...



nothing to contribute tho'

[Joe Alesi]

I've got a couple updates. Not that anyone cares (which is apparently quite obvious).

Hello Chops,

Sorry to hear about the negativity, but I think it is an intersting project and a well presented thread with pics, measuremts, etc...as evidenced by the 1500 odd views-.

Keep it up- we are interested.

[duaneage]

Many years ago speakerbuilder magazine featured a lrge OB system. They presented it with 4 woofers IIRC and got bass to 40 hz out of it. The system was very ambient and measuring the output was a bit difficult because the sound went everywhere. The designers concluded that even though it measured rough it sounded pretty darn good, and after a while they preferred it to sealed or vented systems.

[ChopsMX5]

Alright, sorry guys. I guess I was jumping the gun a bit there. I was having a not-so-good day that day and it kind of trickled onto the net.

Anyway, the DCX2496 came in, I installed it, connected the RS-232 cable, got my laptop out, turned it on and it wouldn't boot into Windows! I already had the Behringer software installed and had some setting already made, but obviously couldn't load them at all. The laptop is about 4 years old, and the HD has been giving me a little trouble over the past year or so, so it was only a matter of time.

So with a dead laptop, I had no choice but to enter everything manually. It was really quite simple to do and I had it up and running within minutes. I first set the xover to L-R48 slopes at 754Hz. From there, I adjusted the I/O gains by ear so the Ushers and Altecs blended nicely together. After that, I pulled out my Behringer ECM-8000 mic, plugged it into the xover, placed the mic at my listening position, and let the auto calibration do its thing for the delay. Finally, after all of that was out of the way, I added HP (curves at -12dB slopes) and LP (curves at -6dB slopes) to the EQ section of the DCX similar to those of my old DEQ1024.


Now a few words on the sound...

First thing I noticed is that the signal is very clean and quiet, definately a step up fromt the Rane/DEQ setup. The second thing I noticed is that the DCX is more open and clear sounding.

One odd thing about the DCX is that when it did the auto calibration for delay, it left the LP outputs alone and delayed the horns instead! That is the exact reverse of what should be done (since the horn driver's motor is nearly 9" behind the woofer's motor), but it certainly sounds much better this way. The sound is very coheirent and "there" with this delay.

Tomorrow I'll be working the center channel into the the last set of I/O's of the DCX and tuning that one up. Speaking of which, I just ordered an Usher 15PA driver for the center channel as well. Since it seems that Parts Express is out of the HM's, plus the fact that I'll be dealing with a much smaller baffle with the center channel, the higher Qts of the 15PA should work a little better.


Anyway, here's a few pics...

[ChopsMX5]

Today I got the center channel worked into the DCX. I first set the levels between the woofer and horn by ear, then adjusted the overall level to that of the main channels. From there, I tweaked it a tad by adding just a little bit of a HP boost at 8.87kHz, the same as the mains, but not as much boost. After that, I let my Pioneer Elite receiver do a full system "auto calibration" (levels, delay, minor EQ) for all channels.

I must say, it is sounding very impessive right now. I've played everything from red-label CDs to HDCD's to DVD-A's to even a movie (Cars). Everything, and I do mean everything sounded superb. I have never heard such seamless panning across the front three channels in my system before. Balance, levels, tonality, height... It all sounded very natural and real.

There's just the slightest bit of "thickness" or "chestiness" in the lower midrange in the center channel. I think this comes from the wrong driver being in the wrong enclosure having the wrong duty. I'm sure that once I get the Usher 15PA driver in, mounted to a small-ish OB, and angled slightly upward toward the listening position, that will all go away and it will sound just as good as the mains.

My next day off, I'll fire up SynRTA and see how things measure up. To be perfectly honest, I could probably be happy with the way it sounds right now for good, but I know that once I take some measurements, I'll have some tweaking to do which will ultimately end up with even better results. The good news is, I still have 17% processor power left in the DCX. After that, or if I need more flexability, I'll have to get the DEQ2496. I'm also planning on getting the FBQ2496 pretty soon.

[ChopsMX5]

Another update...

I got in the Usher 15PA driver a week or so ago. Today I finally had the time to install it into the center channel. With a little trimming of the original enclosure (4.23 cf sealed), I was able to shoe-horn the Usher driver in.

As you can tell by the pictures below, I am also trying a slightly different driver configuration just for the heck of it. So far, it sounds pretty darn good and matches up pretty well with the mains from about 100Hz on up. ATM, it's only tuned by ear, but seems fairly close in tonal balance with the mains.

If I can find the time on my next day off, I'll fire up SynRTA and run through the front three channels.

BTW, I also totally rewired the entire system and moved the equipment around a bit. Everything is now on the rack where it should be, IC cables are shorter, tied together and seperated as far as possible from the power cables. The power cables are also tied together. All new speaker wire was run to the front three channels as well.

Anywho, here's a few pics of how it sits right now.

[clmrt]

So sweet. Really nice things going on there.

[timc]

Very nice. I seem to be comming together.

Im wondering about the horn for the center channel. Don't you get reflection issues from the floor when placed like that?


-Tim

[ChopsMX5]

The CC isn't like that anymore, it's back in its original position.