Enclosure type?

[retro soulman]

Hello ! Can anyone help me if there is a name or type of this enclosure ? I got the plans from here but i need the type or name to google it and take some ideas on finish, color, horns etc. Best regards!

[RMC]

Hi Retro Soulman,

Based on the writings on these plans, they are from a JBL home builder's kit, quite similar to the 1979 such kit I have called "JBL Enclosure Information Manual" that came with this type of plans.

One such large plans sheet I have has this title: "Baffle panels for 8 and 5 cubic feet enclosures using JBL musical instrument and professional series bass drivers."

These are for bass-reflex or vented-box type enclosures. There's not really a cabinet model name or number for those boxes, except to say they are appropriate for the woofer(s) identified below the plan, and maybe some other(s).

I guess in terms of finish, horns, etc. you'll have to "play that by ear" as they say. Unless you find on the Net someone who built the same project box, where you could possibly get some ideas. Hoping this can be of any help to you. Regards,

Richard

[retro soulman]

the drivers i got in my hands and i can "play" - try with are a pair of d140, a pair of k140 , a pair of 2220h and a pair of Gauss 4580 (paper dustcap). Do i have to build the ported or bass reflex version best? Now i use a pair of 4530 but its low end is very limited in my small living room...

[BMWCCA]

Well, the sketch on the bottom is essentially and dimensionally similar to a C35. Without further detail, it's really just a preferred dimension for the D130-based one-way, two-way, or three-way system. :dont-know:

[RMC]

Hi Retro Soulman,

For all practical purposes as they say, ported box (box with a port), vented box (box with a vent) and bass-reflex are the same thing (i.e. synonyms). All three designations are a sealed box with a hole (called vent or port) that passes air in and out of the box to help the woofer in reproducing low frequencies.

By analogy, since you have 4530 cabinets, the woofer front wave is radiating directly into the room and the back wave of the woofer passes through a folded horn that also exits into the room. Though the principles are different, think of the vented box's vent or port as the "equivalent" of your 4530 folded horn for the back wave.

Which woofer do you use in the 4530 cabinets?

Other than the D140 I'm less familiar with, among the drivers you have, none is really appropriate to make a subwoofer type speaker. The low frequency excursion capability of these woofers is: K 140 5.08mm, 2220H 3mm and 4580 2.3 mm.

Since you find the low-end of the 4530 very limited, yes it is and its normal the way it was designed, then I would suggest to use the K-140 woofers as the more bass capable among the three.

You can still make decent bass cabinets with the K-140 pair, with a box volume for each driver of 4 cu.ft. NET with a box/vent tuning frequency of 40 hz, as indicated in the JBL Pro Enclosure guide and in the JBL enclosure plans I have. Naturally, you'll have to increase somewhat the above box volume to take in consideration space taken in the box by woofer, bracing, vent, and driver/horn if you add the latter.

Regards,

Richard

[retro soulman]

Hi Retro Soulman,

For all practical purposes as they say, ported box (box with a port), vented box (box with a vent) and bass-reflex are the same thing (i.e. synonyms). All three designations are a sealed box with a hole (called vent or port) that passes air in and out of the box to help the woofer in reproducing low frequencies.

By analogy, since you have 4530 cabinets, the woofer front wave is radiating directly into the room and the back wave of the woofer passes through a folded horn that also exits into the room. Though the principles are different, think of the vented box's vent or port as the "equivalent" of your 4530 folded horn for the back wave.

Which woofer do you use in the 4530 cabinets?

Other than the D140 I'm less familiar with, among the drivers you have, none is really appropriate to make a subwoofer type speaker. The low frequency excursion capability of these woofers is: K 140 5.08mm, 2220H 3mm and 4580 2.3 mm.

Since you find the low-end of the 4530 very limited, yes it is and its normal the way it was designed, then I would suggest to use the K-140 woofers as the more bass capable among the three.

You can still make decent bass cabinets with the K-140 pair, with a box volume for each driver of 4 cu.ft. NET with a box/vent tuning frequency of 40 hz, as indicated in the JBL Pro Enclosure guide and in the JBL enclosure plans I have. Naturally, you'll have to increase somewhat the above box volume to take in consideration space taken in the box by woofer, bracing, vent, and driver/horn if you add the latter.

Regards,

Richard

To be honest i just need a little more bass a little more tight in low to mid volumes , something that the 4530 cant give (the tightness in the low volumes for sure). I believe a reflex box like these on the plans will give the little something ! My 4530 works really nice with the Gauss drivers but now i work them with the d140. I loose some of the bass but i get some warmer and more defined mids. Its a 3 way active system with 2390 lenses on 2445 driver and 2402 alnico tweeter

[RMC]

Hi Retro Soulman,

RE "I believe a reflex box like these on the plans will give the little something" Your belief may be wrong. The boxes on the plans are both 8 cu.ft. cabinets which are considered large size boxes. On the other hand driver Qts has an influence on appropriate box size needed.

4580 Qts 0.23, 2220H Qts 0.17, K140 Qts 0.21 which are considered low Qts drivers. And such low Qts woofers have a tendency to perform better in smaller boxes (medium size). I know my 2205H Qts 0.21 are somewhat similar to some of yours and they're mounted in 4 cu.ft or so vented box...

Larger cabinet size is NOT always a guarantee of better lower frequency performance. It all depends on Thiele/Small parameters of each woofer. Here in my view you're looking at too large boxes for the drivers you have on hand, which will lead to deficient bass performance.

RE "To be honest i just need a little more bass..." That being so, then go back to my suggestion in post # 5 last paragraph and build that type of boxes (i.e. K 140 in 4 cu.ft.net, etc.). The GROSS internal box volume needed should probably be around 5 cu.ft., to get to a 4 cu.ft. NET once driver, bracing, vent, etc. are factored into.

This means you should probably be looking for a 5 cu.ft. gross box plan instead, and mount the driver/horn/lens and tweeter on top of the box. This should do the trick. Regards,

Richard

[RMC]

Hi Retro Soulman,

Looking back at the plans in my JBL enclosure kit I realize there IS a 5 cu.ft. gross box plan included that may be suitable for you, as well as an 8 cu.ft. gross box plan the latter being for TWO K 140 in the same cabinet (equivalent to one K 140 in 4 cu.ft) in case you decide to go the double woofer way... Let me know if you need the above boxes info.

Note that in the JBL Pro Enclosure Guide chart # 6 for the similar E 140 (though this one has an even lower Qts of 0.17) the enclosure INSIDE dimensions given lead to a 4.38 cu.ft. GROSS box volume, which seems optimistic in real life, with only 9.5% overvolume, to get to a 4 cu.ft. net box volume when driver, bracing, vent and losses are factored into. The effective such box volume may well be more around 3.5 cu.ft. or less depending on construction and/or configuration details. The lower Qts E 140 may get away with this, but you have the K 140.

Richard

[retro soulman]

Hi Retro Soulman,

Looking back at the plans in my JBL enclosure kit I realize there IS a 5 cu.ft. gross box plan included that may be suitable for you, as well as an 8 cu.ft. gross box plan the latter being for TWO K 140 in the same cabinet (equivalent to one K 140 in 4 cu.ft) in case you decide to go the double woofer way... Let me know if you need the above boxes info.

Note that in the JBL Pro Enclosure Guide chart # 6 for the similar E 140 (though this one has an even lower Qts of 0.17) the enclosure INSIDE dimensions given lead to a 4.38 cu.ft. GROSS box volume, which seems optimistic in real life, with only 9.5% overvolume, to get to a 4 cu.ft. net box volume when driver, bracing, vent and losses are factored into. The effective such box volume may well be more around 3.5 cu.ft. or less depending on construction and/or configuration details. The lower Qts E 140 may get away with this, but you have the K 140.

Richard

Thank your for the infos! I would prefer the one woofer versions , its always good to have spare woofers cause you never know... Plus its easier load for the amplifiers !

[ivica]

the drivers i got in my hands and i can "play" - try with are a pair of d140, a pair of k140 , a pair of 2220h and a pair of Gauss 4580 (paper dustcap). Do i have to build the ported or bass reflex version best? Now i use a pair of 4530 but its low end is very limited in my small living room...

Hi retro,

I would stay with 4530 boxes, and I would not change the box, as I expect the results would be not better then with mentioned box.
concerning the bass section reproduction (my experience) using 150 Lit bass-reflex box, 2235 has fare better results then E140.

regards
ivica

[retro soulman]

Hi retro,

I would stay with 4530 boxes, and I would not change the box, as I expect the results would be not better then with mentioned box.
concerning the bass section reproduction (my experience) using 150 Lit bass-reflex box, 2235 has fare better results then E140.

regards
ivica


Maybe you are right , maybe its better to upgrade my 2390 with something better and cleaner in sound. What about smith horns :)

[RMC]

Hi Retro Soulman,

The reply in post # 10 is difficult to follow in the present context (with no justifications given) since you have identified the drivers you have on hand and "can play or try with", but he names others... Whereas I try to make good use of what you have available.

Also my understanding is that the 4530 (with 4580 or D 140) are not changed or replaced (like thrown away) since you like them. The box I suggested is in my view an addition to your "collection" since you mentioned wanting a little more bass.

As for expected results would not be better (with no reasons given), I disagree. From the JBL data available for 4530 and also from a few quick vented-box modelings I did in Winspeakerz there IS a gain to be made, not huge but still worthwhile.

The 4530 with 2205 driver has an F3 of about 55 hz as shown in the JBL Low frequency Enclosures document. I modeled the same driver in a 4 cu.ft vented-box tuned at 40 hz as suggested in the JBL Enclosure guide (to compare with same woofer) and I get an F3 of about 45 hz, so a gain of about 10 hz lower bass. Then I modeled the K 140 in that same box and as expected I also get the same F3 of about 45 hz, again the same 10 hz or so gain. These were modeled with the usual QL 7 and half-space loading.

Note the three basic T/S parameters needed to model a vented LF box are IDENTICAL for the 2205 and K 140: Fs 30 hz, Qts 0.21 and Vas 297.3 L. These three allow calculating the box size ratio (Alpha), tuning frequency ratio (H) and cutoff frequency (F3) ratio.

In my view this box fills the requirement of a little more bass wanted. As for "get some warmer and more defined mids" note the K 140 has a little more rising low-mid response being a musical instrument driver, which may suit you. Finally, the advantage of the K 140, over the other two drivers I know (i.e. compared to those you have on hand) is the larger cone excursion capability of K 140 in case you want to add some bass EQ or beat on it a little...

Let me know if you still want the JBL 5 cu.ft. gross box plan info for single driver.

Richard

EDIT: With a medium size box of 4 cu.ft. net (or 5 cu.ft. gross), it is also easier, if need be, to move the box around in order to try some box placement options and benefit from free low-frequency room gain.

[ivica]

Maybe you are right , maybe its better to upgrade my 2390 with something better and cleaner in sound. What about smith horns :)

Hi retro...,

Hmmmm, if mentioned 2390 is attached with 2441-AL, it would be so easy to say "...upgrade my 2390 with something better and cleaner in sound.....", but to realize that and reach really ".......something better and cleaner in sound......." would be very, very difficult task. May be something like A290 Yuichi (2-inch throat) horn with internal fins would be respectable trial. Unfortunately such horn can be find "here and there" as it is respectable in size, and so easy to be (re)-produced. A kind of CNC 3D machinery would be needed either made from wood or a kind of plastic. 3D printer solution is possible too, but in any case a lot of work has to be done in the file (documentation) preparation, in order that all the parts to fit each others. I wish You good luck in finding proper solution.

regards
ivica

[cooky1257]

I'd measure the T&S parameters of your pretty long in the tooth drivers before doing anything as I'd wager they wont be to spec so you are flying by the arse of your pants...

[retro soulman]

I'd measure the T&S parameters of your pretty long in the tooth drivers before doing anything as I'd wager they wont be to spec so you are flying by the arse of your pants...
yeap maybe its time to upgrade my horns or horn drivers !

[Stevedel]

I have been considering building a single cabinet using the plan for a 130a bass, 175DLH and N1200 crossover in a 16 ohm system in my garage. I have an old Fisher 90X tuner, a Heath mono preamp and E-bay (where I expect to find a tube Mono power amp).

I have a pair of 130a JBLs in excellent condition but hate sending them to exile in the garage. I do, however have a 16 ohm 2220b bass speaker.

Looking over specs for the 130a, 16ohm, and the 2220b, I cannot see any difference except for the number. The 2220 being the "Pro" equivalent to the 130a.

Am I correct in my reasoning?