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Author Topic: TMS4s HF Horn Flare Question  (Read 6429 times)

Adam Biscow

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TMS4s HF Horn Flare Question
« on: December 02, 2017, 01:28:50 PM »

Hey all, my first post here, been lurking for a few years.  I picked up 4 TMS4 cabinets fairly cheap and have started the refurb process.  Unfortunately, the only Turbo drivers left in the boxes are original TS LS-1801Es.  The mids have been replaced by Eminence LA-10850s and the HF are JBL 2425.  What I'm looking for are a couple of replacement horn flares for the HF.  2 are original and 2 have been replaced w RCF H3709 flares.  Was able to source 2 more RCF flares in the UK.  Really would like t keep the original horns but want everything to match obviously.  Thanks for any help or suggestions and listening to my babble.
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Mac Kerr

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Re: TMS4s HF Horn Flare Question
« Reply #1 on: December 02, 2017, 03:19:44 PM »

Hey all, my first post here, been lurking for a few years.  I picked up 4 TMS4 cabinets fairly cheap and have started the refurb process.  Unfortunately, the only Turbo drivers left in the boxes are original TS LS-1801Es.  The mids have been replaced by Eminence LA-10850s and the HF are JBL 2425.  What I'm looking for are a couple of replacement horn flares for the HF.  2 are original and 2 have been replaced w RCF H3709 flares.  Was able to source 2 more RCF flares in the UK.  Really would like t keep the original horns but want everything to match obviously.  Thanks for any help or suggestions and listening to my babble.

It’s been a while since I dealt with TMS4s, but IIRC the high frequency horn was no big deal. They were kind of beamy, and fairly narrow coverage. You may be better off with the RCFs, but with the changed horn, driver, and mid driver you should probably triamp them rather than rely on any internal passive crossover not designed for that setup.

Mac
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Adam Biscow

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Re: TMS4s HF Horn Flare Question
« Reply #2 on: December 02, 2017, 03:25:50 PM »

It’s been a while since I dealt with TMS4s, but IIRC the high frequency horn was no big deal. They were kind of beamy, and fairly narrow coverage. You may be better off with the RCFs, but with the changed horn, driver, and mid driver you should probably triamp them rather than rely on any internal passive crossover not designed for that setup.

Mac
I plan on doing that.  The original crossovers are gone and were replaced by an Eminence 3K highpass filter.
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Adam Biscow

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Re: TMS4s HF Horn Flare Question
« Reply #3 on: December 02, 2017, 03:58:51 PM »

I plan on doing that.  The original crossovers are gone and were replaced by an Eminence 3K highpass filter.
Had another question as well.  Is there any reason the 10" when mounted on the turbomid device should physically touch the back of the phase plug?  Im thinking this is not right and Ill make a spacer for it.
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Mac Kerr

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Re: TMS4s HF Horn Flare Question
« Reply #4 on: December 02, 2017, 09:56:14 PM »

Had another question as well.  Is there any reason the 10" when mounted on the turbomid device should physically touch the back of the phase plug?  Im thinking this is not right and Ill make a spacer for it.

It should not.
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Adam Biscow

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Re: TMS4s HF Horn Flare Question
« Reply #5 on: December 02, 2017, 11:19:35 PM »

It should not.
But I should make it as close as possible.  Was reading approx 6mm.
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Art Welter

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Re: TMS4s HF Horn Flare Question
« Reply #6 on: December 03, 2017, 12:03:42 AM »

But I should make it as close as possible.  Was reading approx 6mm.
Adam,
The Eminence LA-10850 X-max is only 2.9mm, XLim is 10.4mm.
Crossing at 250 Hz the voice coil would likely burn up before reaching X-max, so 6 mm would be OK, going closer is probably not a good idea unless the profile of the LA-10850 matches the phase plug exactly.

If you measure each of your HF horns you may find that the the old 2425 driver unit to unit differences are more than the horn differences. Unless you are getting a real deal probably not worth replacing the fiberglass Turbo HF horns, which probably cracked and were replaced. Support the drivers if they aren't already...

Art
« Last Edit: December 03, 2017, 12:07:17 AM by Art Welter »
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Adam Biscow

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Re: TMS4s HF Horn Flare Question
« Reply #7 on: December 03, 2017, 12:20:40 AM »

Adam,
The Eminence LA-10850 X-max is only 2.9mm, XLim is 10.4mm.
Crossing at 250 Hz the voice coil would likely burn up before reaching X-max, so 6 mm would be OK, going closer is probably not a good idea unless the profile of the LA-10850 matches the phase plug exactly.

If you measure each of your HF horns you may find that the the old 2425 driver unit to unit differences are more than the horn differences. Unless you are getting a real deal probably not worth replacing the fiberglass Turbo HF horns, which probably cracked and were replaced. Support the drivers if they aren't already...

Art
Hey Art,  6mm it is then as the Eminence is a close match but not exact.  Understood about the JBLs.  And yes, I'm sure the original HF horns cracked.  One of the originals still in there is cracked from over tightening the screws in the front and from the driver not being supported well.  In my research online I see some  TMS4s that had the HF replaced with this RCF model.  Its an exact match height wise and just a shade wider.  For me these are going to be part of a weekend warrior rig.
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Steve Payne

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Re: TMS4s HF Horn Flare Question
« Reply #8 on: December 03, 2017, 01:10:49 AM »

Had another question as well.  Is there any reason the 10" when mounted on the turbomid device should physically touch the back of the phase plug?  Im thinking this is not right and Ill make a spacer for it.

Definitely not.  The original 10" driver was a Fane.  The dust cover was glued in concave rather than the normal convex placement.  This conformed to the shape at the back of the phase plug and allowed the required clearance.
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Adam Biscow

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Re: TMS4s HF Horn Flare Question
« Reply #9 on: December 03, 2017, 10:46:55 AM »

Definitely not.  The original 10" driver was a Fane.  The dust cover was glued in concave rather than the normal convex placement.  This conformed to the shape at the back of the phase plug and allowed the required clearance.
The dustcap on the Eminence driver is convex.  I should rephrase about it touching.  When I pulled the drivers, there was a slight mark where I assume it rubbed.  Looking at all 4 the mark is noticeable only on 2.  Whoever owned these before me just threw them in there.   
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ProSoundWeb Community

Re: TMS4s HF Horn Flare Question
« Reply #9 on: December 03, 2017, 10:46:55 AM »


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