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Anybody...Sentry IV bassbin vs Lascala Bass bin


Wrinkles

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I know there are many of ya'll that have been chasing audio nivana longer than me. So, the EV bassbin is almost twice the size of a LaScala bass bin.

The EV Sentry IV uses the TL5050 cabinet. Plans below.

http://archives.telex.com/archives/EV/Builders%20Plans/TL5050%20Builders%20Plans.pdf

Has anyone measured the bass response of this speaker and cabinet?

Has anyone compared it to the LaScala bass bin?

I 'm betting a K402 might sound pretty good on top of this.

Thanks,

Wrinkles

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The (flaming) top cabinets were JBL 4560s.

Posted Image

The horn portion of a 4560 (or Altec A7) is about 30" x 20" with a single 15" driver. They have terrible bass, and limited bandwidth mids (150hz~800hz), and are huge.

The above photo shows what replaced the 4560 boxes, a horn loaded 12 with the same mouth area. They are smaller (two are still smaller than one 4560), lighter, more efficient, and go higher.

Ask yourself, does it make any sense to haul around a 4560/A7?

The (flaming) bottoms were EV TL5050s.

One 5050 is 2Pi is a total waste of time, they start rolling off below about 100hz (a LaScala at about 140hz), and they are big and heavy.

The above photo shows a push-pull slot-loaded (PPSL) subwoofer using a pair of custom Eminence woofers (similar to the Klipsch K43). A pair are 107dB/2.83V/1M and are flat to 31hz. They are reasonable sized, have less distortion, are easier to build, have real bass.

Ask yourself, does it make any sense to haul around a 5050?

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I 'm betting a K402 might sound pretty good on top of this.

I don't know anything about those bins.... but I'll say that if you have a bottom end that can be crossed at 450/500, then the K402 will probably sound great with it.

I've heard the K402 on the LaScala bottom, Jubilee bottom and the MWM bottom. It only gets better as you go up in size yet the top was the same in all of them! Go figure.

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Well, I'm going to try the K402s on them. If they go deeper than the LaScalas, then maybe I'll move my LaScalas into the HT with the other 2 LaScalas. Then I guess I could call it a JubSentry or Jub5050 or K4025050 or K402IVA or EVK402 or ?

I bought the EV Sentry IVA pair for $200. The ST-350A drivers and 1823M drivers had their diaphrams replaced 3 years ago and along with new surrounds for the 4 12" woofers. If they should not perform well then I can always put them back on Craigslist where I got them. I thought maybe laying the TL5050 cabinets on their side vs upright might connect the horn better to the floor plane.

We'll see.

Wrinkles

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Wrinkles,

I purchased a pair of Sentry IV bass bins a month ago, I've had been searching for a pair for a number of years. I've refoamed 3 of the woofers and have sourced a reconed 4th that will be delivered over the next week or so. I'm going to slap my Altec 511/902 on top and give them a test drive shortly.

I have fond memories of these speakers when I last heard them in 1980, very punchy, clear and loud, perfect for Rock and Roll.

I'd be interested in your impressions as well as any crossover work you're doing to accomodate the K402s, I believe the Sentry IV crosses the midrange at 400HZ and the tweeter at 3500HZ

Bonder

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Bonder,

I'm betting the Altec and 902 will sound great. My older setup of LaScala with Altec 511A/802d drivers and JBL 2404 tweeters really sounded geat.

I am way busier than I want to be to play around much, but I did swap out the K402 with the EV mid horns and tweeter. The K402 overpowered the IVA bass bin. I was figuring that the IVA bass bin would play deeper. And I think it does. but without any crossover work it will not gel well with the K402. With the total IVA together go lower, but I have not set them up in a room correctly for any serious listening. So, more work and observations to go. I did deterine that the Sonic T amp did not do them any justice. With Bottlehead Paramour 2A3 tubes, these speakers sounded pretty good.

I think you are correct on the crossover points. The LaScala/K402 crosses alittle higher around 450 hz I think. I do not know how high the IVA bassbin will reproduce well. Something else I will need to do.

Take Care,

Wrinkles

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Been tinkering with the Sentry bass bins and crossover to my 902/CP25 combo.

DJK: While the article states usable output to 850 HZ there's not much more than 550 hz before it starts to take a nose dive, I started with a 2.5 mH inductor but removed that to squeak a few more db's out.

The 902 driver is another story, can't get it low enough to meet the bass bin at 500 hz, best I can do is about 750 hz(I started a new thread to see if there's anything I can do to get it to reach down any more). If possible I'd like to correct this even though I'm not sure I can hear this dip.

I've played 90% test tones this week so I can't comment on the sound in detail, further listening is required. First impressions are good, the speakers are in the garage so I'm going to move them to the man cave after I'm back from vacation. Will report back in a few weeks.

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  • 1 month later...

I 'm betting a K402 might sound pretty good on top of this.

I don't know anything about those bins.... but I'll say that if you have a bottom end that can be crossed at 450/500, then the K402 will probably sound great with it.

I've heard the K402 on the LaScala bottom, Jubilee bottom and the MWM bottom. It only gets better as you go up in size yet the top was the same in all of them! Go figure.

They do indeed!

post-27549-13819499780618_thumb.jpg

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  • 1 month later...
  • 5 months later...

I lost track of this thread a couple of months ago and looked it back up after a LaScala bass bin question. I have a couple of 500Hz tractrix horns that I have a 2" driver for. Then a 2404 tweeter. Thinking about a esn5800 with AP12-500 crossover setup. Right now I'm trying to decide on another La Scala bottom, dBB or maybe even a Jamboree plan (the woodworking on the last may be too challenging for me at this point).

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  • 9 years later...

Sadly the TL5050 is NOT the Sentry IV, which is 50" in height. The Sentry IV had extended response to 50Hz and 35Hz when stacked as a pair. I know this to be true because we ran 4 of these back in the 70's and blew most other PA's off the stage. The 12" drivers were NOT the EV12L having much lower Fs and foam surrounds..closest to the  published figures for this driver, assuming correct, is the Eminence 12 Kappa Pro with similar Fs, VAS and a Qts of around .2..

 

I continue to be unable to access cabinet drawings for the Sentry IV..so if anybody out there can help??

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On 2/9/2020 at 3:42 AM, david.purton@ntlworld.com said:

Sadly the TL5050 is NOT the Sentry IV, which is 50" in height.

 

The TL5050 is correct for the bass horn cabinet. The height of the Sentry IV includes the sectoral horn on top.

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