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Hey guys...we need a little rallying here... - Page 183

post #5461 of 9857
Jeff Bagby finished up his work on the crossover today. He said he really liked how it turned out.

It's going to be an impressive speaker. Actually.....speaker(s). He designed two models around the same enclosure using 2 different woofers. That should help with 2 different price categories.

Time to get box prices on these.
post #5462 of 9857
Quote:
Originally Posted by Erich H View Post

Jeff Bagby finished up his work on the crossover today. He said he really liked how it turned out.
It's going to be an impressive speaker. Actually.....speaker(s). He designed two models around the same enclosure using 2 different woofers. That should help with 2 different price categories.
Time to get box prices on these.

Did he listen in stereo or just mono?
post #5463 of 9857
Quote:
Originally Posted by smokarz View Post

what's your box's internal volume?
got any pics of your completed speakers?

Never mind. I missed that you were talking internal volume and not external size. I am changing gears and going with a box that has external size of 26" x 14.5" x 10.75" deep.
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post #5464 of 9857
Quote:
Originally Posted by Eternal Velocity View Post

Did he listen in stereo or just mono?

Mono for the speaker design. Once the boxes are cut, I'll send him another one if he wants.
post #5465 of 9857
Quote:
Originally Posted by Eternal Velocity View Post

Did he listen in stereo or just mono?

I think I know what you're hinting at. Jeff is obviously a great speaker designer, but he's never designed anything controlled directivity afaik. Direct on axis can sound to bright, but once off axis they sound just right.
post #5466 of 9857
When he told me he was about done, he said he listened to it in multiple positions, different conditions, and different distances.

He's given me a lot more information on his design, but as you can imagine, some of it is a bit over my head right now.
post #5467 of 9857
I think if you ever met Jeff Bagby and had the chance to speak with him your concerns would go away. I know he knows what he is doing. His past designs have confirmed this.
post #5468 of 9857
Which WOOFERS! wink.gif
post #5469 of 9857
Quote:
Originally Posted by NicksHitachi View Post

Which WOOFERS! wink.gif

Eminence 4012HO would be one of them.

http://techtalk.parts-express.com/showthread.php?234487-Interested-in-building-Econowaves-from-scratch-anyone-familiar

See posts 8, 14, & 27
post #5470 of 9857

Wow cool, nice woofers.  I don't know how I missed that, I'm over there quite a bit. 

 

I had considered the Definimax woofers as probable candidates but their price puts them in the ball park of used JBL stuff.  Eminence's published specs are very nice.  IDK which I would prefer, but having Jeff B design them surely makes them more appealing!

post #5471 of 9857
I also considered this design, but decided to go with the TD12M so that I could have a smaller form factor behind my screen.
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post #5472 of 9857
Oh I'm not worried. I think Jeff's design will be great. I think we're just wondering if he evaluated them the way CD designs excel. I often choose to listen to things in mono. And very specific things.
post #5473 of 9857
Quote:
Originally Posted by Hindikush View Post

Smokarz, A post by LTD02, #4379, page 146. Has a break down for sealed & ported ideal box volumes.


What port size/length would I need to tuned a 1.5cf to 38hz for the TD12M?

I am thinking of the round port.
post #5474 of 9857
Quote:
Originally Posted by bg40403 View Post

I think if you ever met Jeff Bagby and had the chance to speak with him your concerns would go away. I know he knows what he is doing. His past designs have confirmed this.

Not at all concerned; just hoping Jeff gets a chance to evaluate them with the crossfire. There's nothing wrong with designing in mono and in many ways it's a preferred method because stereo can mask things. But the crossfire is a key component of this sort of speaker too, so it's nice if he gets a chance to hear it that way smile.gif
post #5475 of 9857
Quote:
Originally Posted by smokarz View Post

What port size/length would I need to tuned a 1.5cf to 38hz for the TD12M?
I am thinking of the round port.
http://audio.claub.net/software/jbabgy/WBCD.html

Keep an eye on power handling as the M has a limited x-max compared to other AE drivers.
post #5476 of 9857
post #5477 of 9857
Thread Starter 
"Keep an eye on power handling as the M has a limited x-max compared to other AE drivers."

properly setup and crossed that won't be any problem.

most folks will run them with a 2nd order high pass filter at 80 hz or so.

with that in mind, even 500 watts will just take them up to xmax and that is while running north of 120db nominal spl.

hindi, the 2226h is a good driver too. no worries there.

"What port size/length would I need to tuned a 1.5cf to 38hz for the TD12M?"

13 inches long 4 inch diameter or any equivalent.

tuning is based on enclosure volume, port diameter and length. doesn't depend on the driver.
Edited by LTD02 - 10/31/12 at 10:00pm
post #5478 of 9857
Thread Starter 
smok, you might actually get the best performance if you run the 12m full range, -6db at 80hz and cross your subs in around that point.

just a thought if they can be be 2nd order low passed. :-)
post #5479 of 9857
Quote:
Originally Posted by LTD02 View Post

smok, you might actually get the best performance if you run the 12m full range, -6db at 80hz and cross your subs in around that point.
just a thought if they can be be 2nd order low passed. :-)


Thanks. Thinking of using the XO provided by Bill W.

This whole 2nd order and low passed stuff seems to complicated for me.

tongue.gif
post #5480 of 9857
Hey smokarz, as usual LTD02 is right on the money. biggrin.gif There's many ways to go about it, but yeah, for an enclosure 1.5ft^3 tuned to 38Hz, you can use a single round port 4" in diameter, it will be 12.75" long. The -3db point is ~90Hz. A slot port is pretty easy too and no port to buy, just make it! cool.gif Same box, tuning, and F3 point, the slot port will be 1"H 12"W 12"D. The slot port takes less room on the baffle than a 4" round and since you may be close to walls behind your screen, you wouldn't want the port on the sides or back. Worth checking out.

Are you going to be crossing to subs all the time? If so, and you never intend to run them full range you could also tune it higher, effectively lowering your F3 point.

All you really need to do is pick an enclosure size and tuning, build the box, and build the xo from Bill's schematic. Order a couple of Erich's blank SEOS baffles too, huge time saver!
post #5481 of 9857
Quote:
Originally Posted by robotbunny View Post

Hey smokarz, as usual LTD02 is right on the money. biggrin.gif There's many ways to go about it, but yeah, for an enclosure 1.5ft^3 tuned to 38Hz, you can use a single round port 4" in diameter, it will be 12.75" long. The -3db point is ~90Hz. A slot port is pretty easy too and no port to buy, just make it! cool.gif Same box, tuning, and F3 point, the slot port will be 1"H 12"W 12"D. The slot port takes less room on the baffle than a 4" round and since you may be close to walls behind your screen, you wouldn't want the port on the sides or back. Worth checking out.
Are you going to be crossing to subs all the time? If so, and you never intend to run them full range you could also tune it higher, effectively lowering your F3 point.
All you really need to do is pick an enclosure size and tuning, build the box, and build the xo from Bill's schematic. Order a couple of Erich's blank SEOS baffles too, huge time saver!


Hey Robot, thanks I really like your build.

You might sold me on the slot port. How do you calculate the slot port size?

I like to play around with it a little with different enclosure sizes and tunings.

Yes, I'll always be crossing over to the subs, but sometimes I might want to run them direct for 2-channel. I am thinking, perhaps tuning them to around 40-50hz.
post #5482 of 9857
Thanks smokarz. There are many online calculators for both round and square/slot ports, the formula for doing it on paper, and WinISD. I used all three to triple check my work to make it as exact as I could. Since my TD12M is only in 1ft^3, the port volume and driver volume would make a significant impact on final volume and response curve. Wayne Parham mentioned this, that in larger cabinets "less precision" is needed. You can see this evendenced by the minute changes in simulated response with larger volumes, though I've never measured this, I'll take Wayne's word for it. wink.gif

The enclosure is 14.5"W 16"H 13.5"D with double baffle, 50Hz tune, 2-chamber cabinet (waveguide and woofer separate), 1ft^3 with slot port 12"W 1"H 10"D (~120in^3) plus driver volume 0.1in^3. With the double baffle the inner port length is reduced which gives me enough room for the 1" donded Dacron lining to not interfere with port mouth. There are no braces since the box bottom, port structure, and box top (bottom of compression driver chamber) are in such close proximity, it's very solid. I finally finshed the second one and have been listening in stereo for a week. cool.gif

Here's a couple shots of the port and baffle before the sides were installed. The first time I assembled everything at once, port, sides, bottom, top. everything. On the second speaker installing the port first was way easier.
Gluing the fully assembled port to the back of the baffle.
Another view of the port and baffle.

Anyway, you're close though, man. You may as well order the xo components and build the crossover while you decide on the enclosure. Once you've got the particulars sorted out, you'll be making sound soon!
Edited by robotbunny - 11/1/12 at 10:21am
post #5483 of 9857
A point worth noting is that if a ported box is XO'd above Fb, you can use a smaller port, as it will never be driven at full power.

You can see how small by looking at port velocity in WinISD with filters applied.
post #5484 of 9857
^ Something often not considered, yet so true.
post #5485 of 9857
To expand on that, I was considering porting my 2206 boxes to lower F3 by 20 Hz or so.

With such a small box, Fb needed to be 55 Hz to keep from getting a hump at the low end.

IIRC (no WinISD at work), I needed a 14" long 4", and that was giving 30 m/s port velocity.

With a 100 Hz 2nd-order HP, IIRC all I needed was a 3" long 2" port, and velocity with the same nominal 180 W input was only 18 m/s.
post #5486 of 9857
Thread Starter 
noah, why not just run your 2206 mains in small sealed enclosures (0.6 cu ft or so) "full range", then cross your subs in "plus mode" or whatever your receiver company call it around 90hz, which is the -6db point on the mains? this is the approach bag end takes (dr. g. too more or less) ...minimum phase change, minimum group delay...as you go from the low mids to the bass.
post #5487 of 9857
Because that would reduce clipping headroom and increase distortion of the mains amps, and increase flux modulation distortion in the 2206's.
Quote:
Originally Posted by LTD02 View Post

noah, why not just run your 2206 mains in small sealed enclosures (0.6 cu ft or so) "full range", then cross your subs in "plus mode" or whatever your receiver company call it around 90hz, which is the -6db point on the mains? this is the approach bag end takes (dr. g. too more or less) ...minimum phase change, minimum group delay...as you go from the low mids to the bass.
post #5488 of 9857
What internal volume do you guys need for the A&E 12" woofer cabinets?
post #5489 of 9857
According to John (post #4387)


You could go as small as around 1cf tuned around 58hz (green curve). That gets response down to around 70hz F3. Going 2cf tuned to around 50hz would give you an F3 in the low 50's(red). You could go as big as 3cf tuned to 45hz. (light blue) The 1cf option gives a very compact design.
post #5490 of 9857
Thread Starter 
for the td12m: 1.4 cu ft tuned to 50hz gives a reasonably rounded frequency rolloff that is down 3db just below 80hz, which is the target for those running the standard thx 80hz crossover setups. (two 3" ports ~8.75" long or the equivalent slot port)



for the td12s: you could use the same cabinet, but sealed. no ports would make it a little larger, so 1.5 cu ft sealed. -3db point is a little under 80hz. good too for thx mains.

so both could be used in a 1.5 cubic foot cab. the td12m would net 1.4 with ports.

they will need a different crossover to the seos because of their difference in sensitivity.
Edited by LTD02 - 11/4/12 at 11:43am
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