My OB Wild Burro Betsy over Alpha 15 H-frame build

Poultrygeist · « **Reply #40 on:** 6 Aug 2013, 11:23 am »

I'm using small 8 inch subs to augment the bass with my H-frames. Just completed the P.E. 8 inch Dayton with flat packs and really like what it adds. I have the Triska on the other side for the moment. I primed then painted the MDF Baluga matte black ( Behr Ultra sample jar ) using a small roller. Flat paint applied with a small roller shows less imperfections.

I drive the Dayton sub with one of the Yung SD300 plate amps which I freed up. One Yung driving the Alphas in 4 ohm parallel equals the same power as two driving them in 8 ohms but even at that 150 watts per side is really over kill for the efficient H-frame Alphas.

danvprod · « **Reply #41 on:** 6 Aug 2013, 01:10 pm »

Thanks @Poultrygeist and @mcgsxr.

I went ahead and purchased some satin black paint from Lowe's before work this morning as well as a small foam roller. I'm going to give the primer and base coat some time to dry (prob. overnight today) and then sand it down again tomorrow to smooth out the surface a bit mor, fill any more holes/voids, and then give it a shot with the roller and the top coat.

@Poultrygeist, I like your idea for a small bass helper. How do you compare the single 8" pictured below with the triska?

Poultrygeist · « **Reply #42 on:** 6 Aug 2013, 02:32 pm »

The 8 inch Reference Dayton has more authority than the Triska and with the 300 watt Yung will shake the walls, not that I ever would. The efficient Triska is happy with a less powerful amp.

Either work nicely with the H-frames.

danvprod · « **Reply #43 on:** 6 Aug 2013, 03:13 pm »

Cheers, thank you for the listening impressions. I do realize this is a journey and I don't want to do everything all at once. For this week, I am really focusing on getting the h-frame set up and painted. Those will likely be the basis of whatever final system I decide on.

Then I want to develop and refine the top baffles, upgrade to a tube-amp to drive those full-range drivers, then assess whether I need some LF augmentation. I do like the idea of a small 8" driver out of the way.

Poultrygeist · « **Reply #44 on:** 6 Aug 2013, 04:16 pm »

The H-frames offer incredible flexibility. Once you build a pair the fun begins as to what you'd like to try on top. That can be a journey all itself.

Today I'm playing with double Neo's and the Tang Bands. Next week it might be the Zenith alnico's I pulled from an old console. The possibilities are endless.

With the H-frames you hear the bass but you don't feel it. I like to feel the kick drum so the small subs do that well without calling attention to themselves.

danvprod · « **Reply #45 on:** 8 Aug 2013, 05:10 pm »

Zenith alnico's -- that sounds fun! I'd like to try and find some Saba greencones. Those would sound awesome on top of the h-frame as well.

After much deliberation, I decided on Valspar Flat Black paint for the top coat. Undercoating was going to be too expensive ($100+) and a 30 mile drive, and the $70/gal shipped for the Duratex was a bit pricy. Quart of the Valspar from Lowe's was 9 bucks. http://www.lowes.com/pd_47098-4-410.0065050.005_0__?productId=3158889&Ntt=valspar+latex+enamel&pl=1&currentURL=%3FNtt%3Dvalspar%2Blatex%2Benamel&facetInfo=

Also picked up a small, 4" foam roller to roll the pain on smooth.

After that is done, I'll work on the new baffles for the Mark Audio Alpair 10.3s.

Poultrygeist · « **Reply #46 on:** 8 Aug 2013, 09:05 pm »

I'd love to try the MA's but I lack the power to drive any of them.

danvprod · « **Reply #47 on:** 9 Aug 2013, 01:24 am »

Some progress this evening. Got a few hours to work on the new baffles. Decided on the 3" u-frame after simulating in the edge. Should be able to run without any baffle roll-off compensations and mate well with the h-frame. Tomorrow I need to make 12 1" cleats so that the MAs have 1.5" of material to screw into (prob. overkill but oh well) and also mount the metal l-brackets to hold up the baffles. I will prob do a 12" x 1" cleat so that the metal l-brackets also have 1.5" of material to go in.

Then I get mount up the MAs and start breaking them in while I work on finishing the h-frames.

Bad picture in my garage. Full ranges are off-center by 2" in both x and y dimensions to minimize the dipole peak and dip.

danvprod · « **Reply #48 on:** 9 Aug 2013, 01:26 am »

Sorry -- the right way this time...

Poultrygeist · « **Reply #49 on:** 9 Aug 2013, 01:39 am »

They look great!

Poultrygeist · « **Reply #50 on:** 10 Aug 2013, 03:09 pm »

Don't want to steal your thread but since you seemed interested, here's the Zenith wide banders in a cobbled together baffle. Butt ugly but sound is pretty good. The Zeniths came from an open backed tube phono cabinet and I see them on ebay for low prices.

danvprod · « **Reply #51 on:** 11 Aug 2013, 12:17 pm »

I bet those sound great @Poultrygeist!

Going to get back to painting them this morning. I should make some good progress today (hopefully it doesn't get too hot!). Great call on the flat black paint. Really really helps make my marginal woodworking skills look better. I ended up getting the highest quality Valspar flat paint from Lowe's in a quart, and a 4" foam roller kit. Paint went on very smooth.

Also did a combo of bondo and vinyl drylwall mud to clean up the edges. Worked really well. Bondo works SO much better than wood putty. Lesson learned.

Also, with the valspar paint + primer, no need to prime before.

Also, found this amp, a little pricy but interesting and 4-channel...
http://classdaudio.com/specials/4-channel-sds-470-class-d-audio-amplifier.html

danvprod · « **Reply #52 on:** 11 Aug 2013, 08:00 pm »

Here we go! Got them all assembled and starting the break-in period. They already sound AWESOME. I have to run out right now, but I will post x-over specs later this evening. MJQ prestige first-press for their inaugural play. Very happy so far. Flat black paint with the metal-coned alpairs works really well IMO.

MJK · « **Reply #53 on:** 11 Aug 2013, 08:24 pm »

Dan,

Very nice!

I have built a few H frame with OB combinations, all in black, and they have been very flexible allowing different full range drivers. The H frames lay down the foundation and mate well with small and large full rangers in the OB.

What type of crossover(s) and settings did you end up with, where are you headed with the final crossover hardware?

Martin

Poultrygeist · « **Reply #54 on:** 11 Aug 2013, 08:48 pm »

I know they sound as good as they look. Great job!

danvprod · « **Reply #55 on:** 12 Aug 2013, 12:46 am »

@MJK -- I've designed these largely on your white paper on the H-frame + Jordan fullrange. I am crossing over the Alpha 15a h-frames at 150Hz LR2, which accounting for the resonance, brings the x-over point to about 200 Hz. This is where the u-frame tops are rolling off according to the Edge. So I am doing a 200 Hz LR4 for the Alpair 10.3s.

Right now it's all active -- MiniDSP is doing the x-over. Rotel RB-1050 70w/channel for the Alphas and a Jerry's electronics Class-D battery powered amp DIY for the Alpairs (I think it is about 15 watts/channel). Not needing to do any padding of the Alpairs to match the Alphas right now.

Only other EQ I am doing that the moments is the Nelson Pass OB 6 dB 20 Hz Q of 2 peak filter to bump up the low bass response of the Alphas. I've contemplated building a passive x-over once I get everything dialed in, but I am not really thinking that is necessary.

Also, with the alpairs, I am not thinking I need a tweeter at all. Very good treble extension. Once I break them in past the 100 Hr mark, I'll iron out the dipole peak, which should be somewhere around the 375 Hz region given the dimensions of the U-Frame.

@Poultrygeist -- thanks! I am very excited with the way they turned out. I just love the way the Marks look peached on the H-frame Alphas.

JohnR · « **Reply #56 on:** 13 Aug 2013, 05:35 am »

Nice work!

danvprod · « **Reply #57 on:** 13 Aug 2013, 12:09 pm »

Thanks, @JohnR.

Now the question, to grill or not to grill?

Guy 13 · « **Reply #58 on:** 13 Aug 2013, 12:25 pm »

Quote from: danvprod on 13 Aug 2013, 12:09 pm

Thanks, @JohnR.

Now the question, to grill or not to grill?

Hi danvprod and all Audio Circle members.
I always admire people that make things simple.
Your speaker set up is simple and sound good, I am sure.
Nice work.

Guy 13

danvprod · « **Reply #59 on:** 14 Aug 2013, 01:54 am »

@Guy13. Thank you very much. Yes, I was striving to produce a relatively simple, enjoyable audio playback system. I think I am there. I am extremely happy with the way they came out. You can always find things to improve, but I think for the time being I am happy with the point that I am at. I may address my amplification and possibly add a subwoofer as @Poultry has recommended to add some impact to the 20-40Hz region, to supplement the bass from the H-frames.

But that will happy after the MarkAudio drivers have been broke in and I can fully asses the system's presentation.