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So I'm starting to think about the next project. I have a pair of 515B's that have been totally rebuilt by GPA they are beautiful!
I am wondering what everyones opinions on the best cabinet to build for them would be? I only have a pair so I'm thinking something along the lines of a 816 style cab.
What do you all think the best cabinet for them is?
'Best' is a moving target, so what kind of performance over what BW are you wanting from it?
Your options are quite limited to a bass horn cabinet. The 816 is an excellent choice . If for Home Hi Fi.
You can make the cabinets with a veneer .
The 828 cabs are huge and you might not want these
for home use unless your sitting at least 20 feet from them.
If your looking for a horn . I would try the Fostex Radial wood horn retail is 400$
with a 1" throat driver by GPA either 902 or 909.
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"Best" really is a big target isn't it, I'm not really sure what direction to go with them, I guess my thought was to figure out where they would perform the best and then fill in the bottom with a sub and the top with the appropriate horn
They would probably see mostly indoor HiFi and some mild PA, they probably aren't really suited for to much PA use.
I currently have GPA 604's for the home and a pair of 515G loaded 828's that get used for PA both indoors and some outdoor. So as I said earlier I'm not really sure what direction to go with these.
I guess I need to know what BW they are at their best at and go from there, I'm open to any style cab. BR, horn loaded etc.
IMO, 816 would be a step backward from the 828.
Why not consider a "210 split", or something along those lines.
I'd want to exploit the best of what the 515B can do, and i think that's best done by getting them in a bass horn with the lowest possible cutoff.
If you plan to use a sub, forget about the reflex volume of the "standard" Altec boxes and put the resources into the horn flare with the lowest tuning.
This of course is just one opinion from my narrow little mind.
Greets!
OK, since a sub is an option, then I agree that the largest practical compression horn is the way to go, so how long (including CC), large and heavy can you tolerate?
GM
Bowtie, I am actually very interested in the "210 split" there used to be a website with a bunch of pics and info about it but lately I haven't had much luck finding info about it.
Your thoughts to exploit the best of a 515B is exactly what I had in mind.
Another cab. I have looked at is the "Imperial Folded Horn" at the Decware website but I'm afraid it would need more room to sound good than I can give it.
GM, I am actually open to the idea of very large and heavy if that is what it takes to make these guys shine, what is "CC", and how large are you thinking?
GM was kind enough to post the 210 split stuff a while back here, but for the life of me can't remember what the thread was about. A search of the board using those keywords didn't bring it up before my attention span wandered.
Maybe GM remembers, or can post again. If not, I have them somewhere, but I suspect somebody remembers.
There's still an article out there somewhere on Michael Frye's 210 splits, i search to no avail.
Article was in Sound Practices issue #15.
You could try him at this email, 'tis the most recent i have.... [email protected]
<font size="2" face="Verdana, Helvetica, sans-serif">I refer to the Imperials as "EF's" or "eternal fortunes". Having known someone who went this route, trust me when i tell you they'll cost a fortune to build or have built, and you'll spend an eternity finding their new home. Each one is quite literally the size of a side by side refrigerator/freezer.Quote:
Another cab. I have looked at is the "Imperial Folded Horn" at the Decware website but I'm afraid it would need more room to sound good than I can give it.
The Imperial may have done magic for the driver around which it was originally designed, but in person for me they're just huge golden oak albatross' that fail to impress.
One thing i've wondered about a "210 split" is the standing wave effect, and if it merits building them to accomodate angled sides rather than parallel sides as per the original design. Hopefully our senior members will chime in with the verdict.
Not sure what you'd use for a sub, but Old Guy posted a link to these some time ago.
http://www.billfitzmaurice.com/T36.html
I haven't begun building yet, but i have stocked the materials to build 4 boxes in the vertical baffle design, still vacillating on the best woofer to load them with. These seem to be the best ratio of physical size to LF extension out there, at least for my budget.
Greets!
Just a 'quickie' for now:
'CC' = compression chamber, IOW the driver box
Don't know if Frye's stuff is still on the net, but here's what the Wayback Machine has archived: http://web.archive.org/web/200502130...frye/index.htm
I uploaded his SP article awhile back: http://s120.photobucket.com/albums/o...210/?start=all
GM
GM to the rescue- again. http://www.hostboard.com/forums/
i have been using the split 210 for a while , i dont know how to post a pic here??
with the 515b it just is in another league , i prefer it to the a7 cab and 816 which really cannot fit and i had to modify the back , i also tried them in br cabs and did not enjoy it
using the 210 i also got the drivers aligned, having them in the horiziontal position with horn on top also helped a lot in crossover implemation,i use a electronic crossover as well as horn subs
they are perfect in the home if you have space ,sometimes it just reminds me that i am in a small club and the platform stage is the size of the speaker layout
all altec members are wellcome for a visit
Well said. I have been chasing the ultimate LF horn for years. I am willing to dedicate my attic for a straigh horn but have yet to put one thru "Horn Response" that I was willing to invest in. It may be time to just start cutting wood. I did pick up a pair of the Lab Sub drivers to use in tapped horns but there is no reason that I cannot just straighten out the Lab in my attic.
Jim N
Greets!
A variation of the theoretical ideal 515B horn is ideal for an attic app since the space is large enough for the 'compression' chamber Vb and there's plenty of room to fold it in half and dump it into a large enough mouth to pressurize a good size room up to where the Labs would kick in.
GM
Greets, part deux!
The Imperial was designed for a much higher Qts/lower Vas driver, so is ill suited for the 515/416 series without some serious tweaking.
The 210 split suffers from the same parallel wall standing wave and poor mouth termination issues as most of the Altec mid-bass horns, so while they sound pretty good, they're hardly 'ultimate'.
A conical expansion will have the least distortion, but the highest F3 for a given path-length while a hyperbolic the opposite and due to the 515's front vent and specs, a fairly low CR is desirable, so the 825/828's ~1:1 seems the one to use since it's designed for a slightly higher HF cut-off than the 210's 300 Hz XO design point.
WRT to size, using the published specs the 'optimum' horn is a ~2.1 Hz BLH that's nominally flat to its ~290.6 Hz mass corner, but obviously it's not even remotely practical, so I guess it boils down to what you can fit through the narrowest doorway it must pass through.
Assuming a standard American entry way, this would be ~32.5" x 78" o.d.. This yields a ~56.5 Hz mouth cut-off sitting on a rigid floor and perpendicular to it and requiring a somewhat longer than 120" path-length plus CC depth depending on the flare factor to load all the way to Fc. Note that any shape other than round is a compromise and any other than square increases distortion with increasing aspect ratio, so if 'best' really is required, then it won't go low and get through a typical doorway without being built in a number of interlocking segments bolted together.
Problems with a 'best' low Fc alignment is the size/shape of the mouth termination required to keep reflections back to the throat from modulating the driver's response. Others are a too wide an acoustic gap to a typical 500 Hz system for them to sum well at the listening position and the increasing critical listening distance required with decreasing flare factor. Then there's the size/cost of a ~matching efficiency sub system...........
So, all things considered, a relatively narrow BW conical horn is 'best', with which BW depending on the HF XO point and/or how big and/or costly a sub system can be realized.
GM
<font size="2" face="Verdana, Helvetica, sans-serif">Hi Merdy,Quote:
Originally posted by MERDY:
all altec members are wellcome for a visit
I might be interested in taking you up on that, could you email me or PM whether that's possible and where you are? I'm in Brooklyn. Thanks.
Dave
<font size="2" face="Verdana, Helvetica, sans-serif">Greets!Quote:
Originally posted by MERDY:
i dont know how to post a pic here??
with the 515b it just is in another league
sometimes it just reminds me that i am in a small club
You will have to open a Photobucket or similar photo sharing account to upload pics to, then post the image link(s) it generates.
I agree, the only other woofer that I've auditioned that can compete with it other than a few vintage ones is one of the TAD drivers, though I imagine the very expensive GOTO units can.
I agree, the 210/515Bs I had gave a live large venue type performance and I enjoyed it for decades, but for a variety of reasons I wound up getting rid of them and to my dismay found that I preferred the more open sound of dual 515Bs in my old large EBS tuned (~20 ft^3/16 Hz) sub cabs. Apparently the mild throat distortion of the 210s finally got on my nerves at some subjective level and why if I ever horn load them again it will be with a large conical one and accept the consequent narrow gain BW.
Frankly though, I've reached the point where I don't see the point unless only flea power is available since dual 515s have >100 dB sens. and close to an ideal polar response for most HIFI apps mounted either vertically or horizontally depending on the desired coverage angle.
GM
I found this . It's a good looking speaker box.
http://www.hostboard.com/forums/hbmc...2007/06/43.jpg
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I think those are Exemplars? They are supposed to be "good sounding" too.
Dave
WOW, I had to go and work for a couple days and while I was gone this thread took off!
Thank you all for the info and ideas! Hmmm where to start? I'm actually glad to hear the Imperial cab would be a poor choice, I wasn't looking forward to building those suckers!
GM, thank you for all the info. I understand most of your post A few things are pushing my brain and knowledge to the edge, lol, sounds like the proverbial "best" cab is gonna get really big really fast!
Thanks for the 210 split info. it actually sounds like a very good option as far as size etc. especially with regards to fitting thru a doorway.
What are your thoughts on angled side's as bowtie mentioned? They could be opened up from the approximate 17" width to 30" and still fit thu a doorway, would that help the standing wave issue or horizontal dispersion at all?
Also I'm a little confused about one thing, you mentioned "a relatively narrow BW conical horn is 'best' etc" I always thought the 515B was a fairly wide BW driver for a 15 so wouldn't a narrow BW horn limit it? What kind of freq. spread would be considered narrow and/or wide for that type of driver?
Merdy, I was searching 210 split info. on yahoo and stumbled accross a old post of yours and a pic of your system on another board, very nice! I would love to hear them but I'm in north Idaho so I probably won't get to anytime soon!
wow thank you all again for your help and info. I'm sure I've forgotten something and will have more questions!
Greets!
You're welcome!
It is implicit that there should be no parallel horn walls.
The horn's BW needs to be fairly narrow to keep the size reasonable, not the horn + driver's HF response. Three octaves is pretty much the limit for a point source driver depending on the BW and a short one such as the 825/828's is slightly < one octave.
Yes, the 515B's response is fairly wide for a 15": http://www.lansingheritage.org/image...15b/page02.jpg
GM
<font size="2" face="Verdana, Helvetica, sans-serif">Greets!Quote:
Originally posted by selmerdave:
I think those are Exemplars?
Yeah, Jeff Markwart's and John Tucker's take on balancing trade-offs in a high SQ Altec components two-way. I forget all the particulars and lost the SP #9? article in a HD crash, but maybe JM will elaborate.
GM
Hi Merdy,
I didn't seem to get PM or email, could you try again to dave(at)davesmithtrumpet(dot)com? Thanks.
Dave
<font size="2" face="Verdana, Helvetica, sans-serif">No, EBS = Extended Bass Shelf: http://www.diysubwoofers.org/prt/ported5.htmQuote:
Originally posted by MERDY:
.....i would like to make sure that i have got the mouth size correct where the upper end mates with the different horns i will be using.....
G M does ebs mean 6th order.....
.....in new york city you can rent your 40cft boxes for $500 a month.....
Is that all?! http://www.hostboard.com/forums/ I can get at least twice that from all the illegal aliens infesting my area.
Anyway...........
I don't understand why you're concerned with a proper mouth size for mating to the HF horn since this is a function of the throat. A throat reduced to ~66.5"^2 has a ~469 Hz cutoff and since the 515's mass corner is considerably below it, a new XO may be required. Tonally, it will potentially be a better blend overall since both will be horn loaded through much more of the XO's BW.
GM
since we are on this topic i have been planning to increase the 210 flair on one side by adding layers of ply in a step format, i havent rushed to this as i would like to make sure that i have got the mouth size correct where the upper end mates with the different horns i will be using i have tried a lot and love the 203b with 288g, havent tried 329 as i cannot find one , please chime on this
http://i118.photobucket.com/albums/o...15horncalc.jpg
http://i118.photobucket.com/albums/o...16horncalc.jpg
http://i118.photobucket.com/albums/o...5ehorncalc.jpg
http://i118.photobucket.com/albums/o...S/CIMG0481.jpg
G M does ebs mean 6th order , in new york city you can rent your 40cft boxes for $500 a month
the tads need some wattage at idle so some power is needed for them to sing , they do play lower though, for my ears and pea size brain altec wins
selmerdave i pm and e mailed you
thanks for the kind words and support