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Zilch
07-03-2004, 06:17 PM
I found a pair of 4625 cabs on eBay and loaded them with Sub 1500's. The results are surprisingly good, since I don't believe the tuning is optimal. Perhaps you guys will run the numbers for me?

Allegedly, the boxes are 4 cu.ft. The interior dimensions calculate to 4.3 cu.ft., but deducting for the bracing, ports, and speaker volume, 4.0 net seems about right, at least for the E-140's that came in these. Sub 1500 is a little bigger, it would appear.

The ports, a pair in each, are 4" X 5-1/4" deep from the face. Somewhere in the literature, I believe I saw the factory tuning was to 40 Hz. I was going to plug the ports, but I'm not so sure now.

In any case, the bass is tight, low, clean, and effortless. I'm running them on a Mackie M-1400i, with the sub filter set at 63 Hz. If I crank the full 300 W into each that amp will deliver, it's clear the cabinets aren't made of thick enough material, but that's WAY more bass than I need here.

I ran them overnight with the local "boosted bass" FM station playing to break them in. Big difference when I got up this morning. These babies throb oh so nicely now. :D

Alex Lancaster
07-03-2004, 07:09 PM
Why would You cut them at 63Hz????

Zilch
07-03-2004, 07:51 PM
Why would You cut them at 63Hz????

It's low PASS at 63 Hz.

The mains are 4412's right now, running without any high pass, so I just need sub.

Similarly, these will ultimately mate with other Cabarets having 15" woofers.

The other option on the Mackie is 125 Hz. I can switch frequencies easily on the rear panel. When I do that, I perceive directional content from the subs.

There's also a low cut filter on there. I trust I have it "Off." Gonna go check that now. [Might be good if I cleaned them grilles, too....] :p

Zilch
07-07-2004, 05:53 PM
JBL Cabaret literature calls these "4.5 cu.ft." boxes, so I went back and carefully measured the interior dimensions: 28" X 18" X 14-7/8" = 4.3385 cu.ft., less the port volume of 0.0654 cu.ft. = 4.2731 cu.ft. net.

It's 1 X bracing, so the 1" fiberglass insulation everywhere says ignore it.

While measuring, I found and removed a 5/16" flat washer floating in there. (Wondered what the rattle was....) ;)

So, what have I got transfer characteristic wise, and how can I "optimize" them? What happens if I plug the ports?

Test disk: "A Momentary Lapse of Reason"

Mackie actually delivers 425 W into 4 ohms, each channel....


Footnote: I once asked JBL Pro customer service about puting 2226H's in these boxes in lieu of the E140's that are standard, and if any change in tuning would be recommended. "No good. Totally different drivers requiring different boxes and tuning altogether," was the initial response.

When I pointed out that the 2226H data sheet response curve was spec'd using a 5.0 cu.ft. box tuned to 40 Hz, and that the SR Series equivalent that superceded Cabaret using 2226H was essentially the same volume and tuning, it became, "Should work, then. How come you're asking ME?" :confused:

Zilch
07-14-2004, 01:24 PM
Well, this is turning into a monolog, albeit instructive:

WinISD says these 4.0 cu.ft. cabs are presently tuned to 42.5 - 45 Hz. I am clueless as to why they sound so good. Apparently, the Sub1500's are "forgiving" in application, i.e., you can put them in just about anything.

It also says I "want" to tune them to about 27 Hz, which will require extending the ports to 20", achievable using elbows. Yup. Maybe use them clamp-on rubber elbows to test rather than ripping out the existing cardboard tubes. Group delay peaks at 22 ms. Not TERRIBLY terrible....

Plugging the ports gives essentially linear rolloff down from about 50 Hz. Seems this would require EQ to work well. I just don't get in my own analysis why others here suggest a 4.0 cu.ft. closed box is a viable option for Sub1500.

Part of the problem may be that we don't have firm T/S numbers, at least, not posted here. It's difficult to design using floating Vas and Fs. :mad:

BUT, it seems I can't go VERY wrong extending the port lengths to lower the box tuning. So, off to Home Depot and the plumbing supply store....

:rockon1:


Sidebar: I also don't understand why Cabaret gets so little play in this forum. There's few systems sweeter than 4628B with E145, 2118, and 2404, at least to the ears of those who prefer cone to horn midrange. A bunch of these have been appearing on eBay recently. Would only they were mirror-imaged....

And 4612B, with dual 2118's and 2404. Perfect rear/side boxes, no, aesthetics notwithstanding? [This from a 4425/30/35 B380/460 fan, LOL....]

Chas
07-14-2004, 01:40 PM
Well, this is turning into a monolog, albeit instructive

Hey, I am enjoying it! I'll have to find something to house the two I bought at some point when I have finished my four 2235's project.

Please, keep us posted as you go:cheers:

Zilch
07-14-2004, 01:51 PM
Chas: Heh, heh. Maybe you'll help with my NEXT project, then, which is four LE 14A's in a triple-chamber bandpass box modeled on Control Sub5. :D

Just gotta refoam these last two, and start another thread, LOL....

Bought a fifth one as a spare on eBay, but the jerk seems to be stiffing me on shipment, going on two months now. :mad:

Zilch
07-14-2004, 02:04 PM
Giskard: Well, plugging the ports certainly WOULD be easier. I'll try that first.

Mackie Low Pass Filter - Switched: 63Hz/125Hz, 3rd Order Bessel

Alternatively, I have BX63A, which is 12 dB, if I recall, but with boost, and adjustable from 63 to 125 Hz....

Which is preferable with the closed box?




Bo: Yup, I used a combination of those and PE Clio numbers in WinISD, compromising on those that don't agree. There was some discussion of those being from one sample only, and PE numbers being from "not broken in" unit. Hard to nail down without the published specs, which must exist somewhere....


Alas, Giskard's very informative posts seem to have disappeared. He's a phantom poster in this thread, apparently. Heh, heh....

Giskard: Kindly repost, if you would, good sir....

speakerdave
07-14-2004, 02:39 PM
Originally posted by Zilch
There's few systems sweeter than 4628B with E145, 2118, and 2404, at least to the ears of those who prefer cone to horn midrange. [This from a 4425/30/35 B380/460 fan, LOL....][/I]

Yeah, I think this system has potential, but not for hi fi (at least to my taste). If I am reading the crossover correctly, the E145 and the 2118 both run full, so I would expect a distinct midrange emphasis in the sound.

I think Giskard's comments about boxing the sub1500 should always be understood in the context of taking into account the effects of room rise in the VLF. It would be a matter of individual taste for how you want or need the subwoofer and the room to work together.

David

Zilch
07-15-2004, 01:47 PM
Originally posted by speakerdave
Yeah, I think this system has potential, but not for hi fi (at least to my taste). If I am reading the crossover correctly, the E145 and the 2118 both run full, so I would expect a distinct midrange emphasis in the sound.

Hmmmmm. I've never opened up the pair I have to see the crossover, or looked at the schematic, but they do sound good here. It's them I intend to mate with the Sub1500 Cabarets. If the woof and mid are running direct, it sounds like some effort in building or installing a suitable crossover would be worthwhile.

Seemingly, it's a killer combination of drivers in a right size box, as above, worthy of an appropriate "tweak" for home hifi or media room use. One 5-7/8" dia. port, 5-1/2" deep. Alas, multi-driver system response analysis is WAY beyond my expertise here....

YEEOOW, Dusty in there! Need to "exercise" them more. :D

speakerdave
07-15-2004, 02:16 PM
I wasn't aware when you posted that you had the speaker. Personally, I wouldn't touch if I liked it the way it is. You're listening to it and I'm just looking at spec sheets, so already you know a lot more about it than I do. I was just interested because I've been thinking about that combination. That mid/tweeter combination was briefly discussed on another thread recently, and it may be that JBL's handling of it in the 4628 and the 4612 (mid run full and a nominal crossover frequency of 3k) is the only way to get them to work together. Gordon pointed out that when he ran the numbers on the crossover component values the true crossover was more like 4.5k. The problem is that the tweeter doesn't really go down to 3k and an 8," even at that frequency is beaming. The two sources paralleled in the overlap region may help with dispersion, I don't know. The result might be that even though on-axis response may have it's peculiarities, the balance in the wider field may be good. Besides, mid-frequency emphasis is more or less standard procedure for sound reinforcement, isn't it?

You might be interested to know that Gold Sound (you can find them on the web) used that mid/tweeter combination in their GS 11 kit, but I have not seen their crossover.

David

Here's the URL for that GS 11 kit.

http://www.goldsound.net/kit11.htm

Zilch
07-15-2004, 03:55 PM
Originally posted by speakerdave
Besides, mid-frequency emphasis is more or less standard procedure for sound reinforcement, isn't it?


"4628B Keyboard/Reinforcement - Specially designed for organ, piano, and synthesizer, with a superb bottom end for clean pedal tones, the 4628B is characterized by extremely low distortion and a wide frequency range"

JBL Pro's home turf is sound reinforcement, which particularly emphasizes clarity in the vocal range, with high SPL, low distortion. I'm not sure that translates to mid-frequency emphasis, per se, though.

Clearly, the current driver and system offerings reflect this; we don't see many standard full-range systems that port well to home use. Few audiophiles are building around the flagship 2226H 15" as their system woofer, I wouldn't imagine, respectable as it may be.

Assuming the design objectives of the 4628B stated above were realized, it's anomalous in this respect. If you wanted to cut through the band with vocals, you used the compression driver version, 4691B, the most popular. Successors to Cabaret refined and expanded upon that success in both portable and installed systems, as I see the evolution, at least....

We really need to see the 4628B system curves to know the actual outcome.

Well, I've drifted somewhat off-topic here, but Cabarets often show up on eBay at reasonable prices, and I think they're worth considering, even if only as convenient test boxes. Perhaps more here will give them a second look. The 4.5 cu. ft. units ship economically via UPS or FedEx ground.

I'll go plug my ports now.... :p

Robh3606
07-15-2004, 07:45 PM
Well I don't know about 2226's but an E-145 is a great HiFi woofer. You won't get too much below 40hz and you definately need a sub but what you do get is great. Fast lean and clean. Great definition on notes and very good effciency at 98db. The 2118 can be a great midrange driver and the 2404 can also excel. All you have to do is limit there range a bit. Your right the 4628 box is not set-up the way many would like but the driver set is damn good. All it takes is a little imagination and you could make a killer speaker with that line up.

Rob:)

4313B
07-16-2004, 07:12 AM
"Giskard: Kindly repost"

I can't remember what I posted.

"Plugging the ports gives essentially linear rolloff down from about 50 Hz."

Good! Exploit that.

"Seems this would require EQ to work well."

and/or proper bandwidth limiting along with proper room placement. They're going to exploit the natural roll-off of the transducer/enclosure and the natural rise of the listening room.

"I just don't get in my own analysis why others here suggest a 4.0 cu.ft. closed box is a viable option for Sub1500."

Because it is viable and we've been doing this subwoofer/ultrabass crap since the B212 first rolled off the line way back in 1977. Subwoofers are bandwidth limited devices by design. It is fairly pointless to evaluate subwoofers without various filters included. WinISD can't do that for you. Nor can it show the mechanical limitations of the transducer. What might look good in WinISD might mechanically fail under actual use.

The 1500SUB was designed for sealed enclosures. Everything about it is designed to withstand the pressures of operating in an airtight sealed enclosure. It is nice that it is versatile enough to also be used in vented enclosures with excellent results.

If someone posts that they are running 1500SUB drivers in 5 cubic foot vented enclosures or 1.5 cubic foot sealed enclosures and that the drivers are doing everything they could have hoped for, I take them at their word. If they post that the drivers aren't living up to all the hype then I know it's "user error". If they post that they prefer vented to sealed then I can understand that. If they post that they prefer sealed to vented than I can understand that as well.

4313B
07-16-2004, 09:30 AM
Originally posted by Zilch
Alternatively, I have BX63A, which is 12 dB, if I recall, but with boost, and adjustable from 63 to 125 Hz....I'm not sure how well the BX63 would work in this instance. I'd have to evaluate a vented enclosure volume with a 1500SUB that would work with the static EQ boost at ~ 26 Hz. Frankly, I see no reason to use assisted vented alignments with this particular transducer. If one went sealed, the BX63 might offer a bit too much boost unless the volume was really small so response was sufficiently down at 26 Hz to take proper advantage of the boost. Try it and see what happens.

Zilch
07-16-2004, 02:25 PM
Plumbing complete:

[/nick "Wingnut"]

Zilch
07-16-2004, 02:32 PM
Gotta move outta the 4 pi workshop, tho:

mrbluster
07-20-2004, 10:25 AM
Please let us know how the sealed boxes are performing. I would also be very interested to know the results of adding equalization via the bx63a.

Thanks,

Mrbluster

4313B
07-20-2004, 11:22 AM
Originally posted by mrbluster
I would also be very interested to know the results of adding equalization via the bx63a.Ok, I'll check tonight then.

4313B
07-20-2004, 04:17 PM
It actually doesn't look all that bad, give it a try.

Zilch
07-20-2004, 04:34 PM
Originally posted by mrbluster
Please let us know how the sealed boxes are performing.

They sound fine. But they're still in the workshop, out from the wall, not in a listening room. They are smoother and less boomy than they were before I plugged the ports. They peaked up 6+ dB at 50 Hz with the original port tuning, apparently, so, much better now, though less "spectacular" in terms of rattlin' stuff in the room and blowin' back your hair, standard performance criteria here.... ;)

That's rebuilt (but not yet refinished) L222 Disco's behind them, there, and behind those, on the bottom shelves, B380's, the standard fare....


I would also be very interested to know the results of adding equalization via the bx63a.

Looks like the mighty Giskard's gonna produce some curves on these net 4.0 cu.ft. boxes for us here, maybe....

PLEEEEZE? :)

4313B
07-20-2004, 07:19 PM
1500SUB in vented B380 enclosure and BX63

4313B
07-20-2004, 07:21 PM
1500SUB in sealed B380 enclosure and BX63

4313B
07-20-2004, 07:36 PM
1500SUB in 2.0 cubic foot sealed enclosure with 20 Hz high pass bump filter (Q = 2) and 50 Hz low pass filter

(Note - the BX63 is a 26 Hz high pass bump filter and a 63 Hz low pass filter.)

Zilch
07-20-2004, 11:27 PM
From these paramaters:

Qts: 0.30 Qms: 4.91
Vas: 181.2 L Qes: 0.34
Fs: 21.47 Hz SPL: 92.00 dB
Re: 2.90 ohm Pe: 1500 W
Le: 1.55 BL: 20.70
Xmax: 18.00 mm dia: 330 mm
Z: 4 ohm Sd: 0.000 m^2

Let me know if any are erroneous.

WinISD gain plots for 4.0 cu.ft. box:

Blue = Stock 4625 ported
Green = Tuned to 27 Hz
Yellow = Plugged ports

Looks like closed box wants the BX63a, as suggested above by Giskard's more comprehensive analysis. As he also earlier recommended, room rise may make it perfect without assist....

4313B
07-21-2004, 05:06 AM
Just remember that the BX63/BX63A is adding roughly 30ms to 40ms group delay. I posted that graph somewhere on the forum years ago. Running the 1500SUB vented and tuned low adds another 20ms to 30ms of group delay.

Here is what I am currently running and it is staggering.
Notice the hit in efficiency though - not good for people who like their ears to bleed.
4.0 cu ft sealed with B212 filter.

4313B
07-21-2004, 08:51 AM
Originally posted by Zilch
Looks like closed box wants the BX63a, as suggested above by Giskard's more comprehensive analysis.I would recommend building something along the lines of Ian's thread on variable frequency, variable Q active filters.

These can also be fun for subs - http://sound.westhost.com/projects-3.htm

Also remember that applying boost to a sealed enclosure is not like applying boost to a vented enclosure. The EQ'd sealed enclosure is all driver, the EQ'd vented enclosure is usually all vent. The 1500SUB is very robust and can usually take the abuse, a lesser driver run sealed with EQ would simply blow up (ripped spider and/or surround, snapped voice coil, etc.)

Zilch
07-21-2004, 03:12 PM
Originally posted by Zilch
Plumbing complete:

[/nick "Wingnut"]

Of some apparent interest, the port blocks I used here are plumbers' test plugs for leak testing DWV systems in construction. Available from Home Depot, your local hardware store (where I got mine), and plumbers' supply houses, they come standard in nominal pipe sizes. These are 4" ones.

They're a resiliant rubber washer or bellows trapped between two metal plates which expands to grab the ID of the pipe (port) bore when you tighten the wingnut. Cheaper versions have just a screw in the center, probably a better choice where there's limited space behind the grille. Replace the screw with a hex bolt if you really want to torque them in.

You're grabbing the bore in the front panel, for the most part, so there's little likelihood of damaging the existing port. They make a tight, rattle-free seal with minimal cost or effort that is instantly reversible. Look at the several designs available to best suit your application....

Paint 'em to match your panel color (Bo Blue, even,) or let your "mystery" components shine through to puzzle your pals for as long as they keep bringing the brewskis in hopes of you disclosing your proprietary box tuning technology. Tweak the tuning for them occasionally to maintain the requisite interest level. It's all in their heads; mess with it, and enjoy windfall refreshing beverages for the duration....

:rockon1:

Zilch
11-14-2004, 06:37 PM
Look silly, sound GREAT!

[Haven't hooked in the BX63A yet, tho.]

Heh, heh....

Tom Loizeaux
11-15-2004, 06:21 AM
I've been silently watching this thread. I'm very interested in this because, like other Forum members (I presume), I have a Sub 1500 waiting for a decision on a custom cabinet. After following the older thread on the Sub 1500, I was leaning toward a vented 5 cu. ft. cabinet, tuned to 30Hz, driven by a plate amp without EQ.
Now I'm wondering if I should consider a smaller (3 cu.ft.?) sealed cabinet with an EQ'd plate amp.

See, some of us are watching these posts and just trying to learn something.
Thanks for sharing your project!

Tom

Zilch
11-15-2004, 12:37 PM
Now I'm wondering if I should consider a smaller (3 cu.ft.?) sealed cabinet with an EQ'd plate amp.Thanks, Tom. From the number of views, Sub 1500 is a popular subject, for sure, and playing around with them is tons of fun, as you can see. :)

Here's what I can tell you from what I've done so far: As Giskard suggests, the Sub 1500 likes the closed box just fine. The bass is clean, tight, and LOW. Due to room rise, you may find you won't need any EQ, even.

However, be aware that the overall SPL output is as much as 6 dB lower in a closed box, and you'll need a substantial amp to run them at appreciable volume. I see PE has 500 and 1000 W plate amps now, but I have no experience with these.

I'm running my Sub 1500's on a Mackie 1400i, which is 425 W/C into 4 ohms. Just a rough guess from the LED panel indicators, but it seems I'm actually puting 100 W each into them here. If I added the BX63A, which I plan to do, it's clear I'd need that additional power.

My target for tuning the box and running ported is 27 Hz, but, since closing the ports, I'm pretty happy with the results, and I may never get around to extending the ports to try it. If I was using these in a disco where I needed more boom per Watt, it might get some project priority here, tho....

Zilch
12-26-2004, 05:18 PM
Acquired an M552 crossover, so here's what's running the 4625/Sub1500 + 4628B stack now. Note that the 6260 driving the Sub1500's is set to max, and the crossover has them boosted 6 dB as well, while the 6230 is set to half way.

Sub1500's in closed boxes suck up the power pretty good.

I KNOW you'll all be impressed with the fine Tuner/CD/Preamp front end of this rig on top there. :D

"It's a SONY!"

[Sounds good tho....]

Zilch
01-16-2005, 06:25 PM
Mr. Widget suggested just closing one port to retune the boxes lower. One 4" dia. X 5-1/2" long port on this pair then, approx. 30 Hz tuning.

Not good on the MACH if I really cranked them, probably, but I like this tuning best, once I got the PHASE right, of course. Sub1500 is positive phase. DUH!

Those are inverted 4691B's on top there, with 2226H in lieu of E140. Maybe I find a way to squeeze more UHF outta them now.... :p

2404H above the Sub 1500 there? Naw, that'd be CHEATING!

Shall I finish the walls or kill the hum first? Could be it's the UFER....