My OB4A's??

ebag4 · « **on:** 27 Dec 2007, 05:32 pm »

Attached are pics of a speaker I just built using Danny's OB5/7 MTM section and a separately amplified Hawthorne audio Augie OB bass driver. The results are outstanding (subjectively, no measurements yet), I get Danny's excellent MTM sound with the OB bass I have come to love. The 15" Augie is plenty of bass for my small (10.5'x12.5'x8' room), there is no boom, only clean articulate bass. These have only been in service for a day although I did burn in the crossovers and drivers while I was finishing the baffles. I am extremely happy with this compliment of drivers/components. The MTMs are powered by my battery driven 41hz Amp4 w/Jensen PIO input coupling caps, the Augies are driven by Infinity OVTR1 bass amps (100 watts). The source is a Bolder Analog modded SB3 with VH bypass caps. More info to come once I have had more time to listen and measure. Thanks Danny, these sound great!!

Wind Chaser · « **Reply #1 on:** 27 Dec 2007, 05:40 pm »

YEAH! Those are very attractive... Nice work!

Is Danny selling a partial OB-5 kit?

ebag4 · « **Reply #2 on:** 27 Dec 2007, 05:42 pm »

Quote from: Wind Chaser on 27 Dec 2007, 05:40 pm

YEAH! Those are very attractive... Nice work!

Is Danny selling a partial OB-5 kit?

Thanks.
Yes, I asked for the MTM section and he priced it up for me.

pbrstreetgang · « **Reply #3 on:** 27 Dec 2007, 05:46 pm »

Looks Awesome!!!

Philistine · « **Reply #4 on:** 27 Dec 2007, 05:48 pm »

They look fantastic

You did an incredible job on the design and construction.

ebag4 · « **Reply #5 on:** 27 Dec 2007, 05:54 pm »

Thanks guys. They won't stand up to close scrutiny like Denny's or Jim Salk's work but I am pretty happy with the way they turned out.

Wind Chaser · « **Reply #6 on:** 27 Dec 2007, 06:14 pm »

They look very pro and original, sort of like an upright musical instrument.

The two tone combination is very nice. Perhaps a nice high gloss black might be more appealing. Hot damn, you could go commercial with these. A sensibly priced flat packed kit offering of these beauties could keep you busy between the bank and the wood shop.

ebag4 · « **Reply #7 on:** 27 Dec 2007, 06:23 pm »

Quote from: Wind Chaser on 27 Dec 2007, 06:14 pm

...could keep you busy between the bank and the wood shop.

Thanks. My wood shop is the tailgate of my truck (for outside sanding duty) and half of my garage which is connected to the house so I am not quite set up for mass production

.

poseidonsvoice · « **Reply #8 on:** 27 Dec 2007, 07:20 pm »

Ed,

If I saw those at a store I would be expecting a price tag from $5K to $10K. Super job.

Best,
Anand.

hmen · « **Reply #9 on:** 27 Dec 2007, 07:26 pm »

Beautiful work.

If I had to guess I would think they were the work of a top-rate design team.

TRADERXFAN · « **Reply #10 on:** 27 Dec 2007, 08:53 pm »

Really interesting design. I am really curious to hear what this "OB bass" is that I keep hearing about... Good looking work.

I am concerned about the bare fiberglass though -you should try and get those covered in something.

ebag4 · « **Reply #11 on:** 27 Dec 2007, 09:22 pm »

Thanks guys, I'm glad you like them.

Traderxfan, yes I need to complete the acoustic treatment project.

Thanks again
Ed

poseidonsvoice · « **Reply #12 on:** 27 Dec 2007, 09:33 pm »

Ed,

Is that a passive crossover to the OB bass section? Or is it active? Your pictures show a large inductor connected to the OB bass section, making me believe its passive. But you also have a separate amp for the bass section as well.

Best,
Anand.

ebag4 · « **Reply #13 on:** 27 Dec 2007, 09:41 pm »

Quote from: poseidonsvoice on 27 Dec 2007, 09:33 pm

Ed,

Is that a passive crossover to the OB bass section? Or is it active? Your pictures show a large inductor connected to the OB bass section, making me believe its passive. But you also have a separate amp for the bass section as well.

Best,
Anand.

Anand,
The crossover shown is a two way (Danny's design) for the MTM section. The bass amp at the rear of the base has a low pass (200 Hz) built into it, this is the unit that handles the signals going to the Augie (woofer). The speaker wire for the woofer that appears to be coming from the crossover is actually coming from the amp but just running under and through the crossover board.

Daygloworange · « **Reply #14 on:** 27 Dec 2007, 10:17 pm »

Great Job Ed!

I think you did a fantastic job with the design. You have a great eye for lines and proportion.

The marriage of the Auggie driver (which I've read a lot of good things about) with the MTM section of the OB 5/7 should sound really, really good.

It also appears that you've mounted the woofer with a magnet mount. Nice detail on that and the brace for the MTM section.

Very cool.

Cheers

ebag4 · « **Reply #15 on:** 27 Dec 2007, 10:23 pm »

Thanks Denny. Yes, the Augie is on a magnet mount which will ultimately disconnect the Augie from the rest of the baflle by using 3 bolts going through the primary base to the floor. The brace serves to stiffen the top of the baffle and it is also my raceway for the wiring to the MTM section.

MaxCast · « **Reply #16 on:** 28 Dec 2007, 12:57 am »

Very nice Edward.

lonewolfny42 · « **Reply #17 on:** 28 Dec 2007, 07:29 am »

Quote from: Wind Chaser on 27 Dec 2007, 06:14 pm

They look very pro and original, sort of like an upright musical instrument.

Nice work Ed....looking good...

As for a musical instrument....yes....does have the look of a sitar....

bernard991 · « **Reply #18 on:** 28 Dec 2007, 06:25 pm »

Fabulous job ED!
two Thumbs up
am a new to building spkrs , wondering if I could ask you a couple of questions ...can you tell me what is magnetic mounting of the Augie ( by the magnet itself rather than bolting flange into baffle ? ) .. from the photos I cannot really discern .. also the beautiful curved baffle you created for the 15" , is the construction and veneering something you can share with us ? ...vacuum press ?
Big thanks
Bernard

ebag4 · « **Reply #19 on:** 28 Dec 2007, 06:58 pm »

Quote from: bernard991 on 28 Dec 2007, 06:25 pm

Fabulous job ED!
two Thumbs up
am a new to building spkrs , wondering if I could ask you a couple of questions ...can you tell me what is magnetic mounting of the Augie ( by the magnet itself rather than bolting flange into baffle ? ) .. from the photos I cannot really discern .. also the beautiful curved baffle you created for the 15" , is the construction and veneering something you can share with us ? ...vacuum press ?
Big thanks
Bernard

Hi Bernard,
The magnet mount setup that I used is similar to what Darrel Hawthorne put together and illustrated on his website, a pic of it is here:
http://www.hawthorneaudio.com/photos/displayimage.php?album=3&pos=91
Before that a gentleman that goes by Mr Content on the Hawthorne website had done something similar with the B200 driver while on the Decware site as Mr. C I believe. The idea is that you are mounting the driver by its heaviest component, the magnet. In my speaker I will be using 3 bolts in the bottom plate of my magnet mount to pass through the main speaker base and slightly lift the magnet mount and speaker off of the main bass, this will hopefully give me the minimum amount of vabration coupling to the main baffle.

For the curved portion of the baffle I used the kerf cut method, in this case it meant cutting the 3/4" stock 5/8" the way through (experimentation is required). You then add glue in the cuts and bend/clamp the piece, the result is a piece that is as strong as the original stock only bent. When the board you are bending is cut at an angle, there is a wierd result that is hard to describe, just suffice it to say that I had to cut the bent piece after it had set up to get the top flat for trim, prior to cutting it the top is twisted in 3 dimensions which would require a trim that could twist, it would also look a bit odd. I then veneered the curved MDF with a Cheery veneer, no vacuum press though. In fact I built these speakers using only a circular saw, router, belt sander, handsaw and batttery operated drill. I would have normally used a sabre saw as well for the curved pieces but mine died during the first cut so I had to resort to using a circular saw then rounding off with the belt sander, a real pain in the a**.

I hope this answers your questions.