horn system id please

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noviygera

noviygera

Member
Joined 2009
#1
I have come across this photo:
Coaxial_horn_system.jpg
anyone know more about this system or any links to additional info on this design?
 
#5
EarlK said:
( too bad all his pics are missing )
Click to expand...

Super Bad Cat



The mid-bass horn is a 210/211 converted to have non parallel side walls that was a continuing 'thorn in my side' when I cut mine out of some 210s to be part of a 4 way corner loaded system. IIRC he used the same compression box size I'd used for 515Bs with no mods. I don't remember how the flare factor [slope angle] was determined.

GM
 
#7
You're welcome!

They're dual 15", ~70 Hz truncated expo horns in BR cabs:
http://www.lansingheritage.org/images/altec/catalogs/1978-pro/page05.jpg

IIRC he used the same compression box size I'd used
Click to expand...

Who said no rear chamber? 😉 'compression box' is a sealed rear box [chamber] sized to push the driver's Fs up to load the horn properly. If not attached to the horn it would be a high tuned sealed alignment with a big peak in its response [high Qtc].

That said, if the driver had the right Fs, Qts it could be used OB same as the pioneers did: https://i.imgur.com/GYqTr.jpg

GM
 
#12
Whoa, that is one interesting system to study. Perhaps build? Any site of forum where Steve Mac can be found to ask him some questions?

What I like about it is -- 3 way system yet a 2 point source. I believe this is much easier to integrate in a normal sized listening room of about 500 sq.ft. -- my listening space. Traditional 3 way horns are a no go for me.
If I understand correctly, this is a near point source from midbass up. Would be interesting to see how this midbass horn models and the system crossover points....
 
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#17
noviygera said:
Whoa, that is one interesting system to study. Perhaps build? Any site of forum where Steve Mac can be found to ask him some questions?

If I understand correctly, this is a near point source from midbass up. Would be interesting to see how this midbass horn models and the system crossover points....
Click to expand...

Not to my knowledge, but we communicate occasionally and I need to respond to his latest PM, so will ask him if he will share the expo Excel? WS he made.

Really though, if still online, anyone can take the throat, mouth area, axial length off the 210 drawing and 'run the numbers' to get the expansion dims. Hmm, actually, it can be done in Hornresp by using just throat area, axial length, flare frequency IIRC, so could make it a different aspect ratio and/or larger/smaller though of course it won't load as low if smaller.

True point source once digital time delay is used to 'move' the 511's driver back somewhere around/behind the 515's acoustic center at the XO point. Without this it's not that good of a sound system.

From experience I find it hard to believe it sounds fine without some aerodynamic smoothing of the 511, but he claims no.

GM
 
#18
noviygera said:
Whoa, that is one interesting system to study. Perhaps build? Any site of forum where Steve Mac can be found to ask him some questions?

What I like about it is -- 3 way system yet a 2 point source. I believe this is much easier to integrate in a normal sized listening room of about 500 sq.ft. -- my listening space. Traditional 3 way horns are a no go for me.
If I understand correctly, this is a near point source from midbass up. Would be interesting to see how this midbass horn models and the system crossover points....
Click to expand...

Hi folks, Greg alerted me to this post...good to see the community active!
Noviygera, I think you nailed the original intention of developing a large point source. It began looking at old Westrex designs, an article on shading WRT driver in driver, and then the Altec designs. Greg was instrumental in this design so always a shout out there to him. 😉 So, another intention was slightly elevated presentation while seated. The mid bass horn bolts together as well. I built what I call the wedges, which was the hardest part. Once they were done the side walls simply bent to conform.

Recently I removed the bass horns below and replaced them with JBL dual 18” powered sub-woofers.

So from a driver point of view:
2 Fostex T500AMKII horn tweeters
2 GPA 288H alnico drivers
4 GPA 515’s
2 JBL 2242H 18” -> now the dual 18 jbl powereds

Greg’s comments about the 511E’s edges may be true, but inside the home my general feeling is they are not driven like they would be in an auditorium so although I experimented with trying to curl the edges some more, I just couldn’t hear an improvement. My experience in audio was being subjected to the dozens of speakers my Dad and his friends were constantly experimenting with. And those fellas were all Altec, JBL, McIntosh obsessed. God bless them, they knew. 🙂

The amps in my system are Odyssey Audio mono blocks. The owner visited this setup before I added the super tweeters had me turn the system way beyond what I had done and I think it was surprising to him how the system did not blink. Also, he adnitted he had not heard dynamics like this. I know Greg and the gang regularly had issues with flea powered amps and dynamics. I think they were right.

The timing of this thread is interesting as I am moving the middle of next year and it’s not clear I will have the space for the mid bass horns, kind of an open question right now. But, honestly this system exceeded what my kinfolk worked on. I had them in a large room up in the Indy area and the stereo image was astounding. Because of the size, it just feels like you are in an auditorium and smaller speakers just don’t present the same “feel”.

I’m going to try and upload some images a little later.
 
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