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Mid horn question [message #45589] Sat, 16 October 2004 10:47 Go to next message
Russellc is currently offline  Russellc
Messages: 397
Registered: May 2009
Illuminati (1st Degree)
I received my 2123H drivers this morning. They are OEM units still in their original boxes and haven't ever been installed yet, still have their final test tags on. Anyway now I need your midhorn kit, and after looking at all the diagrams on your site & forum, it appears that I must build a small enclosure to go on the back of the unit, correct? If so, what size should it be for this particular driver? About the only discussion I have seen about this said something like "anything over a 1/2 cubic foot" The JBL info says from 1/4 to 1/2 cu ft, so I guess that sounds about right? Is there any tuning advantage to the box size on the rear? What sort of stuffing and amount, if any, should this chamber be filled with, All this is probably in the instructions that come with the mid horn kit and I should just shut up and order it?

Thanks in advance,
Russystems

Mid horn answer [message #45591 is a reply to message #45589] Sat, 16 October 2004 14:08 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18789
Registered: January 2001
Illuminati (33rd Degree)

The midhorn was designed to have an open back, or one that is arbitrarily large. The idea is to have no peaking from a sealed rear chamber. So it should be large enough that it is, in essence, insignificant. That's where the 0.5ft3 minimum figure came from.

I'll send you the seven π plans so you'll have all the dimensions you need, for the midhorn cabinet and everything else.


Re: Mid horn answer [message #45597 is a reply to message #45591] Sun, 17 October 2004 09:04 Go to previous messageGo to next message
Russellc is currently offline  Russellc
Messages: 397
Registered: May 2009
Illuminati (1st Degree)
Wayne let me ask this so I am completely clear on the best way, what type of back do you use on the 7 Pi professional (7PI corner horn, mid horn, high freq horn,) or is it run open backed? I would like to Replicate it as closely as possible! Your Comments on that combination with the stoekit ( spelling) impressed me. Is it still possible to review that thing, or is that over with? What a great idea!

Thanks Again for your time & patience,
Russellc

Re: Mid horn answer [message #45602 is a reply to message #45597] Sun, 17 October 2004 14:41 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18789
Registered: January 2001
Illuminati (33rd Degree)

About the Stoetkit, I'm pretty sure Frank Stuppel is still making it available for demos. And I think you'll love it so do be sure to write to Frank about it.

I sent the Pro seven π plans twice to your Hotmail address. I didn't receive an error message saying they exceeded your space limits so I assumed you got the plans, but I guess not. But I just looked in my address book and found your SBC address, so I've resent the plans there. If you don't get them this time, let me know and tell me an alternate address so I can resend. The plans have the exact dimensions of everything, including the midhorn and its cabinet, so that will tell you everything you need to know.

seven π cornerhorn loudspeakerbass and mid cabinets, side view

Re: Mid horn answer [message #45605 is a reply to message #45602] Sun, 17 October 2004 14:52 Go to previous messageGo to next message
Russellc is currently offline  Russellc
Messages: 397
Registered: May 2009
Illuminati (1st Degree)
Thanks a million wayne, I'll see if the little amp is still available.
Thanks for the plans, the hotmail address just isnt big enough, it takes the other one at SBC. Thanks again.

Russellc


Re: Mid horn answer [message #45606 is a reply to message #45605] Sun, 17 October 2004 15:55 Go to previous messageGo to next message
Russellc is currently offline  Russellc
Messages: 397
Registered: May 2009
Illuminati (1st Degree)
Wayne for what ever reason the crossover downloaded to my brief case, but I can't open it, I think it got corrupted. could we try just the crossover again?

Thanks, Russellc

You've got mail! [message #45607 is a reply to message #45606] Sun, 17 October 2004 17:52 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18789
Registered: January 2001
Illuminati (33rd Degree)


Re: Mid horn answer [message #45619 is a reply to message #45591] Mon, 18 October 2004 13:22 Go to previous messageGo to next message
GarMan is currently offline  GarMan
Messages: 960
Registered: May 2009
Illuminati (2nd Degree)
Hi Wayne. Just to clarity. When you say "open-back", you mean a rear chamber volume sufficently large enough to not impact bass alignment (in this case, greater than 0.5 ft^3). However, a closed back is still necessary to contain back waves.

Can you please confirm the last statement. That means the mid-horn should not be used open-baffled?

Gar.

Re: Mid horn answer [message #45620 is a reply to message #45619] Mon, 18 October 2004 14:26 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18789
Registered: January 2001
Illuminati (33rd Degree)

That's right. I've run them open back and they sound great. But I'd rather close the back, and with a large enough rear chamber, tuning is the same as if the rear were open and the backwave is contained. This prevents the rear wave from causing reflections and intereference, so I recommend it.


Re: Mid horn answer [message #45621 is a reply to message #45620] Mon, 18 October 2004 15:07 Go to previous messageGo to previous message
GarMan is currently offline  GarMan
Messages: 960
Registered: May 2009
Illuminati (2nd Degree)
With my back problem for the past 6 weeks, I've been in no shape to veneer my JBL cabinets, so I've been wasting, ... no, spending my time reconfiguring what I already have. I've crossed a pair of Alpha10 on midhorns, completely open-backed, to my Theatre-3. The transition between mid and hi's is pretty good, but I don't think I have the mid to low transition right yet. I thought I might need to close the back up completely. But that would require woodworking with a bad back...

Would you please send me a copy of the crossover document for the audiophile series. I'm interested in seeing how you approached the crossover with the midhorn. I recognise that attenuation would be different for a direct radiator vs corner horn, so I'll keep that in mind.

thanks,
Gar.

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