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Open Baffle Epiphany!

Tucker99 said:
Some photos of my Isophon open baffles.

I allowed an anticipated small roon small footprint to drive my build.

I drove them with a Marantz 2325 and the sound was surprising good.

However there was a predictable absence of base response with the tone controls flat but I was able to compensate using the tone controls... the base needed to go way up and the kids a goodly way also.
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I guess the Pendragons cured that. I've been eyeing the Tekton OBs
 
nj pheonix said:
I guess the Pendragons cured that. I've been eyeing the Tekton OBs
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I had these Tekton OB's for awhile. Detail freaks and excellent speakers if you augment the bass. Eric sells expensive subs for them but I think H-frames probably sound just as good and for much less money.

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Poultrygeist said:
Hope the MiniDSP works for you. My two analog actives ( Ashly and Behringer ) sit idle in a storage closet. They were not the best match for a SET amp.
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I'm using a Dynaco ST-35 amp (push-pull), my biggest issue is breakup of the Fostex driver when the volume is turned up. I have been temped by the Audio Nirvana drivers, but thought I might try using some kind of crossover first. I heard a system in the Madisound booth at Axpona that was using Minidsp and it sounded great.
 
Poultrygeist said:
The AN Classic 8 is the one David gushes over. Here's an interesting blog on OB's. I have a pair of those Zenith 12" Alnico's and they deserve a good baffle. But this guy really likes his large AN's. But don't miss his section on SET amps. Amazing collection.

http://glowinthedarkaudio.com/openbaffle.html
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Thanks for the link. i suppose if you use 2 speakers in one panel you need some kind of crossover or could I bi amp with 2 different tube amps. Green as they come talking speakers.
 
Bi-amping is the way to go. Your best amp on the full range drivers and another amp for the woofers. If you use a plate amp on the woofers it has a built in low pass Xover. I run my full range speakers full range and straight off the SET amp with nothing in the signal path.

The least expensive decent 2 way active crossover is the $79 Behringer.
 
mkane said:
So just full range and no other speaker.
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Maybe a picture will help. With these OB's I ran the Wild Burro Audio Betsy's full range straight from a tube amp while the Eminene Alpha woofers are powered by an old AV receiver ( 2 channel mode ). There's a fixed 80 hz low pass filter on the woofers. A better solution for the woofers would have been a plate amp like the Yung SD100 which has an adjustable crossover. How did it sound? I liked this inexpensive arrangement enough that I promptly sold the Zu's.

So how did I get the same source signal to two different amps at the same time? If using a single output preamp I used Y cables. If using a plate amp and no preamp I connected the source to it's line in and then connected it's line out to the main tube amp. If no plate amp or preamp I split the source's signal with Y cables feeding both amps.

You really don't need a fancy looking baffle like this as it doesn't impact the sound. I'd suggest 3/4" plywood or MDF 20" wide and 38" tall with the woofer 10" above baffle bottom. Full range driver located 32" above bottom baffle edge and 2" off center. They need to be constructed in mirror image. To support the tall flat baffle you can use the largest "L" or shelf brackets from Lowes. The ones I used in another project were white.

If any of this sounds like Greek you are welcome to PM me.

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I'm the owner of the Glow in the Dark website. I no longer have either of the 15 inch AN drivers. I liked the ceramic magnet version a bit more than the alnico, and i think the efficiency difference had a lot to do with it. I do currently have the AN classic 8 inch drivers mounted in a ported cabinet very close to the design recommended by David Dicks, and it sounds very good driven by PP el84.

I like the Zenith drivers best though, and have used them in the main rig almost non stop for a year now.
 
kunja said:
I'm the owner of the Glow in the Dark website. I no longer have either of the 15 inch AN drivers. I liked the ceramic magnet version a bit more than the alnico, and i think the efficiency difference had a lot to do with it. I do currently have the AN classic 8 inch drivers mounted in a ported cabinet very close to the design recommended by David Dicks, and it sounds very good driven by PP el84.

I like the Zenith drivers best though, and have used them in the main rig almost non stop for a year now.
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kunja, it's great to have you posting on AK. I absolutely love your website and all the wonderful gear you have. :thumbsup:

I have the same Zenith drivers but haven't done much with them yet. Do you think they'll need a tweeter?
 
Poultrygeist said:
kunja, it's great to have you posting on AK. I absolutely love your website and all the wonderful gear you have. :thumbsup:

I have the same Zenith drivers but haven't done much with them yet. Do you think they'll need a tweeter?
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Thanks Poultrygeist! I use them with a tweeter, but in all honesty I think its optional for me and my aging ears.
 
I'll second loving your site kunja. I've got to get myself a pair of those zeniths! I used some 10" RCA alnicos I found in an old cabinet in a JE Labs baffle and they were just wonderful. It started me down the rabbit hole.


Question for any of you guys:

I recently put in a pair of Eminence Beta 12LTAs with ASD1001 tweeters on an H frame. I did the "mods" (removed dust cap, made phase plugs and damped the whizzed a bit) but they still sound pretty harsh on vocals and somewhat closed in (I don't really know the best way to describe it) the mid range just isn't there. I've still only got about 6 hours tops on them but I was wondering if anyone had any experience with them not sounding "right"?
 
It's that exact recipe only with a 1uf cap on the tweeter not 1.33 (didn't have one lying around)

Again, I only have 6 or 7 hours on them- even less on the tweeter. I'd like to think it will open up and not be harsh on voices after a while.

Here they are in all their basic glory!!! I still need to cut out the hole for mounting the waveguide. I was just too anxious to hear them.
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Yes, the SET on the Betas plate amp for the alphas. They sound pretty darn good. I can roll a few other drivers on another board (err. baffle?) to taste, but these Betas were pretty cheap to try out after hearing rave reviews on them. I'll put some more time on them and hopefully see if they smooth out some of the harshness on the vocals.

That bass though is something to experience. :beerchug::naughty:
 
I still enjoy my Beta LTA/H-frames and love their grand sense of scale. They're not as refined as the laid back Tang Band W8-1808s but throw up one heck of a sound stage.

Most days I'm listening to the Lowther DX3s which are my favorite full range speaker so far. "Lit up" is the best way I can describe their sound.

The tweeter I used with the LTA is an old Realistic pod tweeter and it's a good match with it's high sensitivity.

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What is your crossover point between the betas and the h-frames? How are you doing the crossover? What is your SET amp?
 
I use a single .47uF cap between the Betas and Realistic tweeters with both powered by 2a3 Bottlehead Paramours or a APPJ Miniwatt S1.

I drive the H-frames with a Yung plate amp with it's built in crossover dial set at whatever sounds best at the time.

I prefer full range speakers running full range with as little as possible in the signal path. The same goes for Jeff ( Godzilla ) in the previous link regarding the Betas.

Two plate amps are shown in the picture but one is enough. I've also used the Dayton APA150 but two of those are required.

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