Forums - Imperial SO has problems, need help

gexter

Ex Member

Re: Imperial SO has problems, need help
Reply #15 - 10/21/05 at 02:47:19

I wish I knew what a real SO is supposed to be like!
I did not think about your woofer size when I noticed the size of the slot.
It you lay the thing on its side it makes a noticible differance with my hack. I also fire the horn into a corner and the output is higher on the horn than the front where the speaker and slot is. That gives me two sides of extention with it on the floor fireing into the corner (kinda) and a top.
When the top is on and its standing up its output is minimal.
I tried it again on its side with the top off and the horn fireing into the corner and it makes a big diff.

My FS/QTS is the exact opposite of the spectrum.
I sure would like to know what specs the thing is designed for.

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« Last Edit: 10/21/05 at 07:47:02 by gexter »

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dank

Ex Member

Re: Imperial SO has problems, need help
Reply #16 - 10/21/05 at 13:01:32

Gexter
What do you mean by "top off" and "top on"?

Have you tried covering up the slot and firing into a corner? My standard Imperials are indicating that the direct speaker radiations are actually reducing output when the Imperial is firing into a corner. In other words the Imperial firing into a corner does better with no direct speaker radiation going into the corner too. Are you seeing the same thing?

DanK

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dank

Ex Member

Re: Imperial SO has problems, need help
Reply #17 - 10/21/05 at 13:13:48

Stvcmty

From what you are saying, the Madison Executioner X 21 ought to be a good candidate for the Imperial SO.

http://madisonspeakers.netfirms.com/0105/products/rawdrivers.htm

Fs = 31, Qts = .982, 4" voice coil, 200oz magnet, Xmax of .75" I've been dying to try one of these monsters, but the high Qts was scaring me off. Might be worth a try now.

DanK

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gexter

Ex Member

Re: Imperial SO has problems, need help
Reply #18 - 10/21/05 at 15:20:10

sorry Dank
My hack is a corner cab. the horn exit is at the top and the normal corner cab has a flat lid so to speak.
I when I used it against a wall with the lid on ( it was in the middle of that wall) it was really week and I could hear it but not that get your attention bass.
I took the lid off ( the top of the corner cab) and laid it downon the floor with the opened horn exiting into a corner behind my corner TV stand.
The slot was facing into the room about 2 feet away from my TV stand.
The output was substantially better. And yes mine seems to have more output through the horn than the slot. when I stick my head into the horn i readilly hear bass. but when i put my head near the slot the bass is less pronounced.
I would not compare mine to yours because mine was based on what I had thought a SO would be like in a smaller form to fit where I wanted it to.
Mine ended up working better than I thought but I still want to know what makes up Steves Imp SO.
I presently am looking for an addtional amp to power it in my garage to give it a good healthy run.
I will try to post a pic of its intended placement ( untested there at the moment)

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« Last Edit: 10/21/05 at 15:33:27 by gexter »

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stvcmty

Ex Member

Re: Imperial SO has problems, need help
Reply #19 - 10/21/05 at 18:39:28

High QTS normally means sealed box or open baffle. Since the SO is a horn resonator built around a sealed box, my guess is high QTS is good. The thing to watch is how a given driver works with the volume the SO has in its sealed chamber. If it is too big, no problem, add bracing. If there isn’t enough volume, the speaker’s low-end extension will fall off.

Stv

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JohnF

Ex Member

Re: Imperial SO has problems, need help
Reply #20 - 10/24/05 at 03:41:11

I'll just wait for the plans. If I wanted to do try one on my own, then I'd go radical and use the open slot loading for the horn and forget the sealed chamber. ei open baffle bass with horn loaded support of the bottom end. No 5 cube chamber, with a corner to form the final horn flare.....hmmm...OB with horn support on the bottom end where OB rolls off, all in a compact form. That has potential to be a perfect sub.

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Brian

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Re: Imperial SO has problems, need help
Reply #21 - 12/20/05 at 22:17:51

[quote author=dank link=1129662594/0#12 date=1129847111]The speaker I’m using doesn’t seem to model well in a sealed 5 cubic foot box (if I’m using the s/w correctly). Perhaps some nice person out there can check my results to see if I’m doing it right. Fs = 30.5 hz, Qts = .227, Vas = 8.6 cubic feet, 8 ohm, 18” diameter. When I model it in a sealed box of 5 cubic feet my s/w says Fc = 50, Qtc = .37 and Cutoff(F3) = 116. [/quote]
Your numbers look good to me. I do not have software, only a table of values in a book which only go down to Qtc 0.5. Setting Qtc to 0.7 I calculated f3 = 94Hz, Vb = 1.0 cu ft.
With Qtc 0.5, f3 = 103Hz, Vb = 2.3 cu ft. I think your numbers would extrapolate from these.
If your cabinet has a door to give access to the sound chamber, you might throw in some sand bags to reduce the volume to 1.5 cu ft or smaller. This might improve your bass without having to buy a new driver.

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Jet-Lee Ex Member	Re: Imperial SO has problems, need help Reply #22 - 12/21/05 at 19:26:21 When I mde my desktop ImpSO, it was an easy hack scaled way down, like 1:24. I think I'll do a little larger version for my 4x6's I took out of my car. I think I'll use corrugated cardboard.
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Rap Ex Member	Re: Imperial SO has problems, need help Reply #23 - 12/21/05 at 19:39:06 [quote author=Jet-Lee link=1129662594/15#22 date=1135193181]When I mde my desktop ImpSO, it was an easy hack scaled way down, like 1:24. I think I'll do a little larger version for my 4x6's I took out of my car. I think I'll use corrugated cardboard. [/quote] You should open a disco for mice Jet
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Jet-Lee Ex Member	Re: Imperial SO has problems, need help Reply #24 - 12/21/05 at 19:59:18 I know. I've got 1:24 Imperial SO, HouseWrecker, and WickedOne. All using headphones. Thought about CornerHorns, but they wouldn't be 1:24 scale.
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dank

Ex Member

Re: Imperial SO has problems, need help
Reply #25 - 01/30/06 at 13:12:42

I finally re-worked my front panel and tried a couple different 15" drivers, rather that the 18" that was originally installed. All to no avail, as I'm still getting virtually zero output from this thing. Here are some pictures:

http://www.mninter.net/~kuechle/impso15_3.jpg

http://www.mninter.net/~kuechle/impso15_2.jpg

http://www.mninter.net/~kuechle/impso15_1.jpg

Thats a 15" JBL E-140 in there now, and I know that speaker is capable of making some bass.

So, has anyone else out there built one of these things and been able to make it work? I'm about ready to scrap this one.

Dank

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J_Rock Ex Member	Re: Imperial SO has problems, need help Reply #26 - 01/31/06 at 02:22:17 SO you build this off of steve's plans? Or is it an extrapolation. Is it just really quite? Or are getting serious cancelation?
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dank

Ex Member

Re: Imperial SO has problems, need help
Reply #27 - 01/31/06 at 14:01:41

It's from Steves plans. The only modification is that it has a hole for an 18" speaker rather than a 15", and the way it's setup now is theres a 15" speaker installed on an adapter board.

It has to be serious cancellation, thats the only thing it could be, right? I see the speaker cone moving like crazy, but there just isn't much sound. If I cover up the front slot opening its quite a bit louder, but thats the only thing I can do to make this sound better: cover up the front entirely.
I did send a full range signal through it yesterday and it had good volume in the vocal range, just no bass. I think that proves cancellation in the lower frequencies.

Dank

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Brian Ex Member	Re: Imperial SO has problems, need help Reply #28 - 01/31/06 at 16:53:26 This may be a silly question, but I think it's time to cover all the bases. Do you have some other bass speaker to use as a reference standard to verify that your hearing is not damaged in the bass region?
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J_Rock

Ex Member

Re: Imperial SO has problems, need help
Reply #29 - 01/31/06 at 23:18:21

A graph of actuall response like a meter away would work too. If it is indeed cancelation(which I expect is the case.), the graph would gradually slope down to the perfect cancelation frequency then begin to slope upward as frequency goes down further.

Kinda like a normal response with a large dip in the frequencies surrounding the cancelation frequency.

Also, this graph would show exactly what you are trying to describe, or wether there is output or not.

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