Open Baffle w/miniDSP HD -- Hallelujah It Works!

DesertRatt

DesertRatt

All Bark, No Bite!
Finally, it's all together playing music. Seems like it took too long, but I think it will be worth it.

Setup
Full rangers: EV-SP-12B 12" @ 100Hz and above
Woofers: Eminence Alpha 15" @100Hz and below
Crossover/PEQ: miniDSP-HD
Bass Amp: Carver TFM-35x
Full range Amp: Adcom GFA-5200
Preamp: Carver C3

After a few hiccups understanding how to program the DSP, It finally became somewhat obvious how to set it up. Not the best written manual I've ever read, but it's ok.

I can easily see that playing with the DSP can take many more hours. What sounded just right on one CD, seemed a little off on the next. I did 3 hours of twiddling with the laptop connected to the DSP playing music, and finally decided I should settle on something and try it.

The sound is very different from my Magnepan 1.7i. I got the warning from the wife when i dragged these new speakers in: "These better sound as good as the Magnepans!" Or else what? Throw them out?

The EVs were definitely a little shy in the treble, so I cranked in some boost above 6k and that seemed good enough for my ears which go to about 12k. The low end was more solid than my Magnepans. The big difference was the space around vocals. There was more "3D" around every vocal. Space in front, behind, side to side and above. I'm pretty convinced that vocals pouring out of a 12" driver just sound big and spacious compared to other speakers.

I'm not that happy with the appearance. I'm going to have to doctor the appearance.. maybe adding some grill cloth.

Tomorrow, I'll try the REW software and see what that reveals. For today, I'm exhausted!

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A heckuva nice setup. Playing with it to tune to your room/tastes will probably take awhile, but for sure will be worth it.
Love my OBs.
 
fjdds said:
A heckuva nice setup. Playing with it to tune to your room/tastes will probably take awhile, but for sure will be worth it.
Love my OBs.
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Time is one thing I have right now! I'm looking forward to the REW process . That will be a brand new thing to learn--just as the DSP was a new thing. I think the DSP would revolutionize speaker design.
 
tomlinmgt said:
Did you use any sort of "wings" on the sides?
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Not yet. I pondered that when building, but decided to wait and listen first. Right now I think wings would seriously degrade the look of the speakers in the room. As they are now, they have s similar profile as my magnepans--they look slender. Wings near the top will make them look like huge boxes.
 
DesertRatt said:
Not yet. I pondered that when building, but decided to wait and listen first. Right now I think wings would seriously degrade the look of the speakers in the room. As they are now, they have s similar profile as my magnepans--they look slender. Wings near the top will make them look like huge boxes.
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From what I've seen, with an OB it's best if the wing is only on one side for the mid and high frequency (or full range) driver, and both sides for the low frequency driver. Like this...

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and sculpting some curvature into the wings helps make them appear less box speaker-ish.
 
tomlinmgt said:
From what I've seen, with an OB it's best if the wing is only on one side for the mid and high frequency (or full range) driver, and both sides for the low frequency driver. Like this...

View attachment 2737137

and sculpting some curvature into the wings helps make them appear less box speaker-ish.
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That's really elaborate! I will do some experimentation as soon as I can go buy more ply wood. Right now, I'm wingless for want of wingage.
 
Using REW Software

WOW - pretty complicated to setup. It took me about 3 hours just to get my laptop setup, the right cords, the mic setup and so on. I was finally able to run some basic sweeps, and did some fussing with the DSP settings but this is going to take a lot more time. It's quite tedious - probably made more so because I have an old crappy laptop. And, my poor dog absolutely freaks out over every sweep sound, bell-ring, beep, honk, tinkle made by any phone or computer. Then when he freaks out, the wife loses patience and well, the whole affair goes downhill.

What I did manage to determine with confidence is that my EV-SP12s go to 12kHz and then hit a brick wall. No amount of treble tweaking on the DSP will get one iota more treble. So, I will now be thinking of a super tweeter. to add into the mix.
 
DesertRatt said:
That's really elaborate! I will do some experimentation as soon as I can go buy more ply wood. Right now, I'm wingless for want of wingage.
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Also, if you want more low frequency extension and bass strength, my experience is that the 15A's do much better in an h- or u-frame. But that will create the appearance of a box around the 15a's, which you said you aren't keen on. But if you ever change how you feel about that, know that there is more bass performance that can be had from them if you shroud them.
 
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tomlinmgt said:
Also, if you want more low frequency extension and strength, my experience is that the 15A's do much better in an h- or u-frame. But that will create the appearance of a box around the 15a's, which you said you aren't keen on. But if you ever change how you feel about that, know that there is more performance that can be had from them if you shroud them.
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I put an 18" deep box with no back on the BACK SIDE of the woofer in order to have a "stand" for the whole affair. I am reasonably satisfied with the bass although there is a but of peak at 100Hz.
 
Looking nice! There is something refreshing and revealing about the open baffle sound. Kind of like you let the bird out of the cage:)
 
dfoulk said:
Looking nice! There is something refreshing and revealing about the open baffle sound. Kind of like you let the bird out of the cage:)
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Dang! That's a great metaphor. I wish I had thought of that! Yeah, I think you nailed it. What I replaced was Magenpan 1.7i - which I liked quite a bit. But this OB has such a BIG open sound that is very seductive.
Last night I was listening to an old Julie London CD - which is not particularly well recorded - but darn! it sounded so luscious it made up for the so-so recording. I think I can not count myself among the converted.

I am going to add a tweeter today, just to see if It is really needed. I'm also anxious now to try a higher end full range than what I am using. When I suggested I'd be using an EV-SP-12B some folks suggested they were far less than "high end." So, I might try moving up that ladder. The way I made the speakers, it is trivial to plug in a different top or bottom.
 
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DesertRatt said:
Dang! That's a great metaphor. I wish I had thought of that! Yeah, I think you nailed it. What I replaced was Magenpan 1.7i - which I liked quite a bit. But this OB has such a BIG open sound that is very seductive.
Last night I was listening to an old Julie London CD - which is not particularly well recorded - but darn! it sounded so luscious it made up for the so-so recording. I think I can not count myself among the converted.
I am going to add a tweeter today, just to see if It is really needed. I'm also anxious now to try a higher end full range than what I am using. When I suggested I'd be using an EV-SP-12B some folks suggested they were far less than "high end." So, I might try moving up that ladder. The way I made the speakers, it is trivial to plug in a different top or bottom.
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A while back, I had a Tang Band 8 inch full range that worked nicely with a 12 inch Goldwood woofer. I ran the Tang full range, and the Goldwood I rolled off around 250 Hz. with an inductor.
I ended up selling the Tangs, to experiment with some Alnico Zenith's, but if I had to do it again, I would have kept the Tang, W8-2145 I believe was the model. It was an easy to listen to speaker, but had good detail, and it blended nicely with the Goldwood. The high end of the Tang was good enough to me to not need a tweeter.

Presently I took a trip down the nostalgia lane, and just bought a pair of Rectilinear Lowboys, a bass reflex, not open baffle. Lost some of that airy openness, but wanted a change of
pace, and a lower jump for some older kitties that like to relax on a pillow on top of the speakers:)
I am not quite sure how the Rec's will end up, but just might end up pushing them in an open baffle direction. I have already made some changes that would delegate them to non-rectilinear
status by those that need to keep it all original. I have always enjoyed making stuff more to suit me than preserve a museum piece, but that for me is the fun of audio!
 

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dfoulk said:
Presently I took a trip down the nostalgia lane, and just bought a pair of Rectilinear Lowboys, a bass reflex, not open baffle. Lost some of that airy openness,
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A way to get some (most?) of that back is up firing speakers, wideband or midrange, behind the main speakers. Probably not a good idea with your cats.
 
dfoulk said:
Presently I took a trip down the nostalgia lane, and just bought a pair of Rectilinear Lowboys
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For the longest time back in the 70s I had a crush on Rectilinear tall boys. They were one of the most popular speakers at Pacific Stereo. But alas, Dynaco speakers are my budget in that era.

I'm thinking of going to 15" on the full range. My sense is that really big speakers are IT! Maybe those L'il Audio15s.
 
DesertRatt said:
For the longest time back in the 70s I had a crush on Rectilinear tall boys. They were one of the most popular speakers at Pacific Stereo. But alas, Dynaco speakers are my budget in that era.

I'm thinking of going to 15" on the full range. My sense is that really big speakers are IT! Maybe those L'il Audio15s.
Click to expand...
I couldn't afford those Rectilinears back 50 years when I was first drooling over them! The Nostalgia bug rendered my brain senseless, so I had to have them for $175.00, a month ago. My cats love them, and my wife too! With every change I make, they keep getting better, maybe even all the way to open baffle if I take the sabre saw to the backs:banana:
 
tomlinmgt said:
From what I've seen, with an OB it's best if the wing is only on one side for the mid and high frequency (or full range) driver, and both sides for the low frequency driver. Like this...

View attachment 2737137

and sculpting some curvature into the wings helps make them appear less box speaker-ish.
Click to expand...
The potential problem with wings is that standing waves between them produces a definite boxy sound. That boxiness is in the midrange, so having one side open where the midrange driver is makes sense. Also, having the wings non-parallel to each other makes sense too.
 
Ah, wings! Another opportunity for experimentation!

It has also occured to me that some amount of rear damping might be interesting. Right now my full range driver is exposed to collecting dust. I'm considering putting some type of veil over it.
 
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