For you fans of the open baffle - here is a rig that may tickle your fancies. And you can hear it next month in Dallas at Lone Star Audio Fest - LSAF May 14, 15, 16
This is real DIY - all done from scratch.
Photo courtesy of Positive Feedback Magazine
This belongs to my buddy John, but it will be in my room at LSAF. Please drop by for a listen. This speaker was a big hit at LSAF 2008. Don't know what room I'll be in yet, but will post when I know. LSAF is still small enough that it's easy to find anyone.
Basically it's an Altec 605 coax with an 18" Eminence helper woofer. The 605 section is passive, the 18" Emmy is active. See the crossover schematic below.
The 18" is no longer made, alas, but it's a low Qts pro 18. Used here on the open baffle it's crossed at ~40Hz, 3rd order. This low x-over point fights the rising response this driver has on open baffle. 3rd order blends best with the 15" Altec cone above it.
Being a coax -and an Altec Alnico - of course it has tone and vocals to die for. Imaging is top notch, too. The crossover was tweaked for best in-room response in the Embassy Suites. I will probably tweak it further this year, and will report the results.
The idea here is to have a big, but not gigantic, baffle that is very musical with great vocals and imagining - but also has some real grunt. Thus the division of passive mid/high and active woofer. The mid/high section can be driven with a nice little flea amp.
Speaking of amps, I'll have a few there - I like amps - but the star will be a Grant Audio SET amp. Their A-534B 300B integrated. Should really sing with the Altec coax!
I hope you can stop by for a listen and a chat. always fun to meet other DIYers. And it will give you a chance to hear a nice OB rig. One with no secrets.
This is real DIY - all done from scratch.
Photo courtesy of Positive Feedback Magazine
This belongs to my buddy John, but it will be in my room at LSAF. Please drop by for a listen. This speaker was a big hit at LSAF 2008. Don't know what room I'll be in yet, but will post when I know. LSAF is still small enough that it's easy to find anyone.
Basically it's an Altec 605 coax with an 18" Eminence helper woofer. The 605 section is passive, the 18" Emmy is active. See the crossover schematic below.
The 18" is no longer made, alas, but it's a low Qts pro 18. Used here on the open baffle it's crossed at ~40Hz, 3rd order. This low x-over point fights the rising response this driver has on open baffle. 3rd order blends best with the 15" Altec cone above it.
Being a coax -and an Altec Alnico - of course it has tone and vocals to die for. Imaging is top notch, too. The crossover was tweaked for best in-room response in the Embassy Suites. I will probably tweak it further this year, and will report the results.
The idea here is to have a big, but not gigantic, baffle that is very musical with great vocals and imagining - but also has some real grunt. Thus the division of passive mid/high and active woofer. The mid/high section can be driven with a nice little flea amp.
Speaking of amps, I'll have a few there - I like amps - but the star will be a Grant Audio SET amp. Their A-534B 300B integrated. Should really sing with the Altec coax!
I hope you can stop by for a listen and a chat. always fun to meet other DIYers. And it will give you a chance to hear a nice OB rig. One with no secrets.
Attachments
Well done!
It looks a well-proportioned baffle and beautifully made. Pity I can't hear them.
40Hz 3rd order LPF is steep! Is that 18" hungry for power?
It looks a well-proportioned baffle and beautifully made. Pity I can't hear them.
40Hz 3rd order LPF is steep! Is that 18" hungry for power?
😎 a 2.5 OB. I made one fully passive.
This loudspeaker should give a big sound 😀 (2400cm² of area)
This loudspeaker should give a big sound 😀 (2400cm² of area)
Well the 18 is going to be a bit hungry. Much more so than the mid. But that's the nature of Open Baffle. You have to do something to fight the loss of bass - so power is the solution.
Electrically a 3rd order low pass at 40Hz is steep. But acoustically it works out much higher and somewhat less steep. I will try to measure it in-room in Dallas.
It is a big speaker with a "big as life" sound. I like the powered bass. John likes all passive rigs, so he built another. It will be there, too. I'll post pics.
Electrically a 3rd order low pass at 40Hz is steep. But acoustically it works out much higher and somewhat less steep. I will try to measure it in-room in Dallas.
It is a big speaker with a "big as life" sound. I like the powered bass. John likes all passive rigs, so he built another. It will be there, too. I'll post pics.
a.wayne asked here about imaging with the wide baffle, but somehow his post got mangled.
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The other big OB rig.
Here is another, even bigger, OB rig that will be at LSAF.
Photos below of the front & back under construction. It's 2x18" + 1x10" + tweeter. All passive crossover. Plays deep and clean. Nicely efficient, too.
It should be up at the Nor Cal DIY meet on the 24th.
diyAudio - Nor Cal DIY Audio Group Spring 2010 Meeting
Drivers are:
2x Goldwood 18" for bass. Run in parallel for a 4 ohm load.
Goldwood GW-1858
1x 10" Seas
Seas Prestige A26RE4 (H1411)
Dome tweeter TBD. (John has a lot to choose from)
Anyone going to the Sacramento event, please let us know what you think.
Here is another, even bigger, OB rig that will be at LSAF.
Photos below of the front & back under construction. It's 2x18" + 1x10" + tweeter. All passive crossover. Plays deep and clean. Nicely efficient, too.
It should be up at the Nor Cal DIY meet on the 24th.
diyAudio - Nor Cal DIY Audio Group Spring 2010 Meeting
Drivers are:
2x Goldwood 18" for bass. Run in parallel for a 4 ohm load.
Goldwood GW-1858
1x 10" Seas
Seas Prestige A26RE4 (H1411)
Dome tweeter TBD. (John has a lot to choose from)
Anyone going to the Sacramento event, please let us know what you think.
Attachments
Hey Stig. Thanks! I know you do a lot of great work on OB. 
The dipole peak EQ is hidden in the woofer to mid crossover. That's part of the reason for the low freq, 3rd order filter. It all kinda works out. If I get a chance in Dallas, I'll do some measuring. But as you know, in-room measurements are hard down that low.
The dipole peak EQ is hidden in the woofer to mid crossover. That's part of the reason for the low freq, 3rd order filter. It all kinda works out. If I get a chance in Dallas, I'll do some measuring. But as you know, in-room measurements are hard down that low.
Hi,
Forgot to ask, the 605, in the first post, is the rear cap of the compression driver removed? 😀
And, why not give hi-Z amp a try? Maybe it can surprise you 😉
Forgot to ask, the 605, in the first post, is the rear cap of the compression driver removed? 😀
And, why not give hi-Z amp a try? Maybe it can surprise you 😉
No, the rear cap is in place. I might try it off just to hear what the back splash will do. Good idea.
Hi-Z amp. Got one? 😉
Hi-Z amp. Got one? 😉
To answer the "does it image with that big baffle?" question.
yes. I know that many folks just don't believe that wide baffles image well, but I have not found that. Now it may be easier to get a small baffle to sound spacious, but it seems to me they are just more omni than the wides. That can be a very pleasant sensation, but it isn't real imaging to me.
Having attended a lot of audio shows and DIY meets and heard a lot of speakers over the past few years, I have to say that rare is the speaker with good depth. Width, space, air - yeah. But depth, no. And the few that I've heard with real depth have almost all been wide baffle. (but not all wide baffles had good depth)
Of course the coax mid/high has some great advantages for imaging. The drivers are already aligned on the X & Y axis. And if the crossover is done right the phase will line up and the Z axis will come into line, no digital delay needed.. Coax drivers have their faults, but for alignment they are hard to beat.
So I am certainly not in the "wide baffles don't image" camp. Because for me - done right - they do it better than anything else. That's my POV. 😉
yes. I know that many folks just don't believe that wide baffles image well, but I have not found that. Now it may be easier to get a small baffle to sound spacious, but it seems to me they are just more omni than the wides. That can be a very pleasant sensation, but it isn't real imaging to me.
Having attended a lot of audio shows and DIY meets and heard a lot of speakers over the past few years, I have to say that rare is the speaker with good depth. Width, space, air - yeah. But depth, no. And the few that I've heard with real depth have almost all been wide baffle. (but not all wide baffles had good depth)
Of course the coax mid/high has some great advantages for imaging. The drivers are already aligned on the X & Y axis. And if the crossover is done right the phase will line up and the Z axis will come into line, no digital delay needed.. Coax drivers have their faults, but for alignment they are hard to beat.
So I am certainly not in the "wide baffles don't image" camp. Because for me - done right - they do it better than anything else. That's my POV. 😉
Your baffles may be wide in terms of inch or cm, but they don't look wide acoustically if compared to the drivers' diameters. Beaming of the drivers need to be accounted for.
An acoustically wide baffle is 3" driver on 45cm baffle, as extreme example.
I know from AudioCircle that you're not fond of the Orions. Can you share us your subjective comparation to this one? Where do they stand out and what are the limitations or tradeoffs?
btw. the photo lacks scale... can you stand between them just fo get a grasp of how big those 18" drivers are? 😀 😎
Gainphile, a loudspeaker with more area sounds bigger, better. The mid of the orion is fantastic, clear, detailled, etc. but in my opinion not enough because you have 2700cm² versus 900cm² 🙂
Well, you know, this is DIY forum 😀
Changing a couple of small resistors can make (almost) any Lo-Z SS amp become one with 20 Ohm output impedance 😉
About the wide baffles that cant image.... dont agree! I did have some rather wide baffles during my own OB experiments, although I ended up with no baffle... just nude drivers. The thing that impressed me most with the wide ones was the imaging - very vivid, deep, wide soundstage, although tonal balance suffered because of bad directivity. My current baffle-less speakers image very well, they are far more accurate than the large baffles, but their soundstage is somewhat smaller in all dimensions. What you want is all a matter of your own preferences.
Well yes, if you put it that way. The baffle is not too wide compared to the drivers. And John's dual 18s are even slimmer. It's just when I read "narrow baffle" I think 6-8". I was thinking absolutely instead of relatively, I suppose.
I'll post a photo of me between the speakers we they get to Dallas. And I'll post more info and listening impressions, too. Will try to get visitor comments if I can.
As for the Orions, yes, I was underwhelmed. Nice speaker, but never very lively. Good balance, no obvious faults, but no real life. Strange. Never had that feeling of either a singer right there in front of me, or the wall opening up and reveling the symphony hall. That's the sort of thing that the Altecs do for me.
(Don't want to turn this into an Orion thread. Linkwitz is a lovely man, but his speaker - as I heard it - was not to my taste).
Hi Panomaniac,
You are not the first people who have this feeling 😱 Good speaker, very versatile but no dynamics, no life etc.
The magnesium driver needs very good electronics to come to life. It is a very neutral driver but if you don't put good amplifiers the sound is lifeless
Waiting for your report
🙂
>>> 1x 10" Seas
>>> Seas Prestige A26RE4 (H1411)
Nobody seems to care about hi Qts drivers when having bass help. I tend to agree with this. Only seem to need hi Qts when it's the only driver on the baffle... unless there is a tweeter too.
Godzilla
>>> Seas Prestige A26RE4 (H1411)
Nobody seems to care about hi Qts drivers when having bass help. I tend to agree with this. Only seem to need hi Qts when it's the only driver on the baffle... unless there is a tweeter too.
Godzilla
I've heard the magnesium seas (several different drivers in different speakers with different "break-in" times), in different applications with *VERY GOOD ELECTRONICS* and have *never* heard them "come to life".
Clarity yes, even spacious (..depending on the application), but always dynamically "stunted" (or "compressed" sounding) and always *dull* (..not a freq. balance issue). Dido for the nomex tweeters that Seas produces that I've heard. (..by contrast some of the older aluminum tweeters that Seas produces have a bit of "life" to them.)
Well John's new rig (post #6) uses high Qts drivers. In fact on baffle they have a Q of about 1.2! Now that surprised me because John usually doesn't like high Q woofers. So I asked him:
Pano: "you like those goldwood hi-Q drivers OK?"
J.B. "Yep"
Pano: "But don't they have sloppy bass?"
J.B. "Nope"
Pano: Don't they flop around down low or boom?'
J.B. "No."
Pano: "So these cheap 18" woofers are giving you clean, low bass?"
J.B: "Yes. But I'm out of them by 250Hz. And there's 2x18" a side, so plenty of surface area. And X-max is more than they state. They don't have to work hard."
Pano: So you really like 'em?"
J.B. "Yep, maybe the best bass I've ever heard."
😱
I have not heard them yet, but will be sure to give a full report from Dallas. Hearing is believing, and I have not heard them yet. We shall see - or hear.
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