DIY multicell horn

Mirrophonic,
The 210 and 211 enclosures are bigger!!!
Actually, the 815 is a very similar, truncated cousin. The 211/210 horns extend several inches farther at the mouth though the width (flat panel to flat panel) is the same. Here are the horn dimensions (exluding the overall enclosure):

Width of 210 horn mouth (flat sides): 34"
Width of 815 horn mouth (flat sides): 34"
Height of 210 horn mouth: 59.5"
Height of 815 horn mouth: 44"
Depth of 210 horn: About 30"
Depth of 815 horn: About 23"

The other significant differences on the 815 is the absence of any bass-reflex chamber, a fully-enclosed driver chamber designed to reduce woofer travel, and the apperently thinner plywood on the curved panels to (my guess) reduce weight for shipping and suspending purposes.

As soon as I get my hands on some 210s and or 211s I'll A to B compare them with my 'opened-up' 815s.

After living with LF horns I simply cannot go back to direct radiating enclosures. I can only anticipate that the 210 will be that much more of a good thing.

MP

Mirrophonic,
Plans for all these enclosures are readily available. Check the Lansing Heritage site. They have a great Altec library there.

MP

>After living with LF horns I simply cannot go back to direct radiating enclosures. I can only anticipate that the 210 will be that much more of a good thing.

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FWIW, I had 515B loaded 210s at one time (three actually) and later turned two of them into corner loaded compression horns. Very impressive. Much later I sold them and put the four 515s into two 20 ft^3 vented EBS aligned cabs in the same corners and I can't really hear any difference beyond what you would expect due to the lower efficiency. Tonal balance, usable 'slam', transient response, etc., all sound the same except they require more power now (still within Xmax) and go two octaves lower (16Hz Fb).

For HIFI, an acceptable tradeoff IMO if you have sufficient/clean power and two corners available.

GM

GM,
Would you expound on that system as I am not familiar with EMS low frequency enclosures? The prospect of another octave is exciting to me as you can see on my avatar to the left.

The factors I cherish most about my Altec horns are the directivity and efficiency, the result being the reduction of the effects room acoustics and trademark transient response. Or simply really loud and clean! http://www.hostboard.com/forums/

MP

EBS, Extended Bass Shelf. Basically, you make a cab that's a bit too large and tune it below Fs. This raises the F3, F6 points of course, but the corner boosts it some and if there's any room gain of note, the bottom end also. Without the corners, it has a response similar to a large sealed cab, though with a bit more gain.

If stuck in the corners, the corner is a conical horn of sorts, so there's not much difference in a typical size HIFI room. Where it becomes an issue is higher up, so you want a mids/HF horn that's 90deg or less. WRT transient response, there's a minor measurable difference between the modded 210s and the EBS, but I can't tell it. As for 'loud n' clean', well, dual 515s and a clean 110W/chnl is as loud as I care to go in my room.

Indeed, the 511s are the limiting factor and why I didn't mind parting with the 210s, which I got to fill a large 'great' room in a previous home. Actually, the cabs I'm using now were originally my 'subs' to fill in below the 210s.

GM

OK, I'm going to skip the separate thread because I've been doing
more quick caculations and it appears that the 210 is a fairly good choice
for a bass horn.

Initially I was concerned about the lack of depth which I suspected of
leading to an insuficiently low 'flare-rate frequency' - which should approximate
the cut-off frequency.

For reference I'm using Dr Edgar's design curves for "wall position" Tractrix
bass horns (the 210/ A4,A2 could be considered quasi 'wall-loaded'
because of those added baffle panels). To convert Tractrix to Exponential,
I add about 10% to the length.

With the 210's approx. 380 sq in throat area, and I make the cut-off freq ~80 hz,
the flare length can be as short as 30" (thanks to the large throat area
with dual drivers).

With the 'wall' loading, horn loading should extend to below 50hz
and with corner loading: who knows ? As GM said, they should be very impressive !

The avatar shows some floor-loaded concrete bass horns in Italy .
(click 'member rated' for enlargement)

Mirro,

Looking at your new avatar..... What did you do? Accidentally turn the volume too high & blew up your house? http://www.hostboard.com/forums/

GM & VOTT,

Some good experimentation GM and the results are not a great surprise to
me.
The results being an undetectable difference between a good direct radiator
and a 210 theater horn.

I think the reason may be the compromises in theater horns which deserves a
separate thread and I will be Devil's Advocate by asking :
"Are Movie Bass Horns Any Good ?"

Mirrophonic,
Not only do your calculations support Altec's own data, they also suggests that Altec engineers actually knew what they were doing. Of course my ears have been telling me that for years. http://www.hostboard.com/forums/

It is the bottom octave, however, that I must solve. That's where the brick or concrete horn comes in!

MP

VOTT
In case you missed the picture of the Italian commercial
bass horns, I have reloaded it to the avatar.

I am thinking of similar construction for my bass horns:
Flat top & bottom wedge, curved sides with tractrix contour to reduce length,
single 15" driver with 0.6 throat-to-driver ratio.

Precedents:
Dinsdale: Tractrix bass horn
Babani: Simplified wedge construction for horns
Edgar: Design curves for Tractrix bass horns

Thanks Mirrophonic,
I have made drawings similar to that. That is, incorperation the horn into the stage cavity. It makes perfect sense.

MP

My wife can read me like a book, I'd never get away with it!

I think I'll just have to build my dream venue and call it a business http://www.hostboard.com/forums/

MP

Lots of municipal parks have summer concert series. Can you imagine the draw you would get with an in ground, poured concrete, LF horn system! Maybe even combined with a water feature that distributed a fine mist to cool the audience when the music starts smokin'. Well, maybe I'm getting a little off topic.

Ray

"That is, incorporation of the horn into the stage cavity"

...OR in a split-level sunken living room....

"Honey, you'll really love this split-level home I've found" http://www.hostboard.com/forums/

It seems a lot people like LF horn in here but i noticed that LF horn is used less and less.(I mean the modern speaker) Why???

Larry,
It has everything to do with size. It is easier to transport smaller direct radiating LF enclosures in tour-sound applications. There are some sacrifices though---and directivity is the main one (IMHO). I must say, however, there seems to be a number of folded sub-bass horn systems in current use which definitely speaks for itself.

Long live horn systems!!!

MP

Larry,
I'm sorry, you probably meant home systems not tour-sound. I'm still thinking 'venue', which might as well have a permanent house horn system anyway!
Nevertheless, again size seems to be the issue along with big amplifiers (which can drive little inefficient speakers) and strong glue (so the speakers components don't fall apart). The public has been so passified over the last half century or so on direct radiating systems that most people have no idea how much better horn systems can sound (again in my humble opinion).
Even my hodge-podge 815/511B horn system (which only horn loads to abit below 100Hz) is jaw dropping to most people,...and with guitar speakers no less!! Ah!!! There's gotta be somethin' to this horn thing!

MP

VOTT,
When you say that you "opened up" the 815's for improved
sound, I have an alternate idea: You could close this
front port and open the rear speaker access (if they
have a rear panel like the 210's) creating a "Shearer/Mirrophonic" effect.

To eliminate/attenuate the rear waves, add wings - or
a wing if corner mounted - or cut a hole in the wall to
make adjacent room/garage the 'infinite rear chamber' (do it while your wife is out shopping http://www.hostboard.com/forums/ )

I like your infinite baffle idea. My garage/workshop/doghouse/home-away-from-home/"my space" is located adjacent to my basement den where all the audio is. If I turn the common wall into an infinite baffle mounting for the LF, I could mount the 1005's to supply the den and mount the 511-90's in the opposite direction to supply the the garage. I like that idea.

Charles:
Yes, with the right drivers and a little EQ, you can have
superior bass - in two rooms !

Here's a picture of one I/B installation:
http://home.comcast.net/~ttriff//page3IB-Gallery3.html

Mirrophonic and Charles,
My 815s have front slots like a 210 but I made them closeable for experimentation. I'll try opening the backs and see how it sounds though I have no wings. If I wall mount the enclosures I will be infinitely baffling my drivers directly into the neighborhood. Of course, If I toss a couple of reverse-phased 511Bs out there It'll be a great block party!

Hi all,

Anyone tried added wings on A5 or A7(828 enclosure)? Do you think the sound is better?

I have seen some Japanese add wings on A5 ,A7 from Japanese audio magazine. Anyway, wings would not affect the sounds get bad that I believed.

>My 815s have front slots like a 210......

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Oh really?! Did you add them, or do you mean the 817, which has a smaller horn and vertical vents on each side?

http://www.lansingheritage.org/image...pro/page05.jpg

====

>Anyone tried added wings on A5 or A7(828 enclosure)? Do you think the sound is better?

====

Yes, but you have to extend them up to get the max benefit, like the original 800 VOTT, though I placed the horn in the baffle directly above the midbass horn since it was for a HIFI app.. Due to the wrong horn offset, you need to bi-amp and use electronic time delay to align them at the XO point.

http://www.lansingheritage.org/image.../800/page2.jpg

GM

Been there, done that alot in my time. http://www.hostboard.com/forums/ I wonder how many of the discarded 825s I chopped down into stage monitors are still being used by garage bands.

GM

GM,
My 815s have been severely modified: "Mr. skill saw, meet Mr. loudspeaker enclosure"..."Oh no, not the skill saw!! Ahhhhhhhhhh!!!.....Hey, that wasn't so bad, now I respond to 40 Hz...Cool" http://www.hostboard.com/forums/

Yeh, I did just the opposite. I took a pair of 'horn only' enclosures and expanded them into big vented enclosures. One of these days I'll put some proper drivers in the monsters and see what they're really capable of http://www.hostboard.com/forums/

Hi all,

Last week, i heard a pair A5 with original 828 cabinet(1005 horns, 288B drivers and 515B woofers). The sound is very strange, this A5 has midrange only. I have a look at both drivers and woofers, they both in mint condition. Is that A5 original sound?

Yes, the 515 won't sound 'full' in such a large cab without significant series resistance, which of course lowers efficiency considerably. Best to seal off the horn section and add a 'sub' in the lower section of the cab.

GM

Hi GM,

How to add a "sub" in the lower section?

Hello,

I've found by chance this post, and I'm very happy to see that my site has been seen from other countries... And thankyou for your interest into our (my brother and I) horns. They are not copies of Ledauphin horn and the construction is different (and lesss risky) even if the result is the same (and much pleasant to look !). I have to scan the pictures of the construction and put them on line.

As it takes a long time to translate the whole site in english, it's still in French...

If you have any questions about the content of the site, you can write to me !

[email protected]

>Hi GM,

How to add a "sub" in the lower section?

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Not much to tell. Block off the driver area to create a compression chamber, romove the two vent baffle boards and replace them with a sub driver/vent(s) baffle board to suit. I recommend adding some bracing.

If there's archives, I mentioned this awhile back and Roland (haven't seen him post in some time now) liked the idea, added a JBL 2245? and seemed quite pleased with it, though I'm sure other drivers will work also. I used a 411-8A in mine way back when they first came out. Really, with these new low Vas/low Fs sub drivers, using two in a bipole layout would be best, but then you would have to cut up the cab, which for some would consider it heresy. Due to efficiency differences, bi-amping is best.

GM

GM

Thanks

Hi, GM

I have seen a people turned his 828cabs up side down. Bass horn on the bottom. Then used 2 pieces of plywood to cover the bass horn. Just leave a 1 inch gap as vent. The 515B mounted on the baffle. This way can makes the cab provide more rich bass. Although LF and HF not on the same point. but Sound stage still very great.

have you or anybody has tried?

No, it never occurred to me.

GM

GM

I know some peoples would like to add a sub woofer(s) to their VOTT system.
But I interested to your mentioned that relating to add a sub woofer(s) in 828 cabs. Which one of sub you would suggest? Cause that lights up my greed to quest for the higher music reproduce.

Best regard

Roland's choice of the JBL 2245H appears to be a good one. Altec's 3156 looks good also, if you can find some.

GM