Should my Sunn 2x15 reflex cabinet have insulation?

MrHeadfirst · #1 05-19-2010, 10:17 PM

I opened up my old, old Sunn 215 bass cabinet recently, and found that there is no insulation present at all. This is a reflex style cabinet with the port running up one of the veritcal sides. was there insulation to start with? will it get any cleaner or less boomy sounding if i were to add any?
just wondering...

billfitzmaurice · #2 05-20-2010, 07:19 AM

An unlined cabinet is a defective cabinet. Line it fully with an inch of open cell foam, like a mattress topper, or an inch of polyester upholstery batting, or a half inch of felt carpet padding. The cab response will be improved considerably.

craig.p · #3 05-20-2010, 08:32 AM

Sounds like a 215BH. I'm with Bill, HOWEVER... mine (late '70s) didn't have insulation either, none that I could see through the port anyway, and it sounded great. It sounded very "woody," lots of character, lots of "grunt." I'm sure it would've looked like utter hell plotted on response/phase graphs, but I remember getting lots of compliments on its sound. So if you like your cab's tone the way it is and if you take Bill's suggestion, make your foam installation something you can change your mind about after trying it out for a week, because it WILL change that cab's characteristic sound.

edbass · #4 05-20-2010, 10:53 AM

Quote:

Originally Posted by billfitzmaurice

An unlined cabinet is a defective cabinet. Line it fully with an inch of open cell foam, like a mattress topper, or an inch of polyester upholstery batting, or a half inch of felt carpet padding. The cab response will be improved considerably.

I agree totally, but several months ago I bought a highly touted Orange OBC115 to experiment with and found there was absolutely zero insulation. Just a driver in a box.
It didn't sound awful but kind of suprised me; how much could a little foam cost? They certainly don't skimp on the retail price...

I have numerous Sunn 215's, '72 and older, and all of them have insulation of one form or another.

billfitzmaurice · #5 05-20-2010, 11:07 AM

Quote:

Originally Posted by edbass

I agree totally, but several months ago I bought a highly touted Orange OBC115 to experiment with and found there was absolutely zero insulation. Just a driver in a box.

IMO the quality of a cab is revealed by those things that you can't see from the outside. The benefits of cabinet damping have been well known in both the professional and amateur loudspeaker design community for over 40 years. I can't imagine any manufacturer not having the knowledge that it is a required design element, or knowing that it should be in there but leaving it out for the sake of saving a few bucks. But stranger things have happened.

craig.p · #6 05-20-2010, 12:23 PM

Hey Bill, I'm wondering if they auditioned a prototype without the stuffing, and it was grins and dropped jaws all around. Wouldn't be the first time something "incorrect" was put into production simply because it had Dat Mojo, right?

My 215BH was my favorite cab in my whole history of playing. Boy would I like to hear one with drivers that could "take it" instead of those chintzy stock speakers. I'm still kicking myself for having sold it. And for not having bought a second to make a pair.

KramerBassFan · #7 05-20-2010, 12:45 PM

Quote:

Originally Posted by craig.p

Hey Bill, I'm wondering if they auditioned a prototype without the stuffing, and it was grins and dropped jaws all around. Wouldn't be the first time something "incorrect" was put into production simply because it had Dat Mojo, right?

My 215BH was my favorite cab in my whole history of playing. Boy would I like to hear one with drivers that could "take it" instead of those chintzy stock speakers. I'm still kicking myself for having sold it. And for not having bought a second to make a pair.

More likely it was a cost cutting measure that wasn't deemed NECESSARY, and was therefore scrapped to save $14.43 or how ever much it would have actually cost.

billfitzmaurice · #8 05-20-2010, 12:48 PM

Quote:

Originally Posted by craig.p

Hey Bill, I'm wondering if they auditioned a prototype without the stuffing, and it was grins and dropped jaws all around. Wouldn't be the first time something "incorrect" was put into production simply because it had Dat Mojo, right?

A loudspeaker designer with all but the most modest knowledge base would never consider building an undamped cab. Beancounters, OTOH...

MrHeadfirst · #9 05-20-2010, 08:24 PM

well, im glad to say, that while i had it apart, i lined it with carpet padding, it does sound very good. i like this cabinet quite a bit. in fact, i really love it. my only complaint is that it really lacks in the "modern" sounds area. i really like the design of the cabinet, and i notice the older mesa boogie 2x15 cabs are made in a very very similar fashion. do you have any input on the design of these bill?
i have been really kicking around building one of your cabinets, and i actually purchased several plans too, im just a little scared of them..lol. i had also kicked around building myself another one of these cabinets, then i read an old post of bill's concerning this design. You had stated that this cabinet in size was a better match for a pair of 12's and was a bit small for a pair of 15's... could i increase the dimensions on a new build to incorporate 15's? or would the gains be not worth it?
lastly...should all the surfaces in the cabinet be covered? i left the speaker baffle and the mouth section of the cab without covering...it seems to sound quite good. very tight with the bottom end. my particular cabinet is loaded with celestion BL-250 speakers.
while im going on...why doesnt anyone ever talk about the celestion green label or orange label bass speakers on here? its always the kappa's...just wondered.

billfitzmaurice · #10 05-20-2010, 08:48 PM

Quote:

Originally Posted by MrHeadfirst

well, im glad to say, that while i had it apart, i lined it with carpet padding, it does sound very good. i like this cabinet quite a bit. in fact, i really love it. my only complaint is that it really lacks in the "modern" sounds area. i really like the design of the cabinet, and i notice the older mesa boogie 2x15 cabs are made in a very very similar fashion. do you have any input on the design of these bill?

I'm not familiar with either, but older designs tended to use boxes too small for deep response. It wasn't a huge issue, as the drivers weren't capable of it either.

Quote:

should all the surfaces in the cabinet be covered?

Yes, although I don't know what 'mouth' refers to.

Quote:

while im going on...why doesnt anyone ever talk about the celestion green label or orange label bass speakers on here? its always the kappa's...just wondered.

IMO they are inferior to the Kappalites and Deltalite IIs. Celestion does make some better drivers, like the NTR10-2520D, which is equivalent to the 2510, but they're much more expensive.

MrHeadfirst · #11 05-20-2010, 08:51 PM

cool, thanks for the info...
sorry for my not so technical terminology. I was referring to the port area of the cabinet.
the port runs the vertical length of the cabinet. just a simple bass reflex design as i would describe it.
thanks for your input. it is always appreciated, by me.

KrisH · #12 05-20-2010, 08:57 PM

The Sunn 215BH I had in the 80s also lacked any insulation inside. But it was designed as a rear-loaded folded bass horn, so that somehow seemed right. (After all, you don't see carpeting covering the horn surface on a high-end driver.) Anyway, it sounded great and put out the volume.

MrHeadfirst · #13 05-20-2010, 09:00 PM

yeah, this things does seem to generate a pretty insane amount of volume without really trying too hard. even when i play without pa support, my t-max head never breaks 1 on the volume knob. cabinet just is in your face, i have not been let down by it.

craig.p · #14 05-21-2010, 05:34 AM

> it was designed as a rear-loaded folded bass horn

Now I'm confused. Mine was like MHF's cab -- direct radiator with the chamber vented off to the right-hand side. Not a folded horn. Maybe it wasn't a BH after all. Maybe it was an RH. Wish I'd kept the catalog.

billfitzmaurice · #15 05-21-2010, 06:47 AM

Quote:

Originally Posted by KrisH

The Sunn 215BH I had in the 80s also lacked any insulation inside. But it was designed as a rear-loaded folded bass horn, so that somehow seemed right.

The early Sunn cabs that claimed to be rear-loaded folded horns, the 200S and 2000S, were not. They were bass reflex with tapered ducts. The 215BH is a rear loaded folded horn, but the horn is half the length necessary to work down to the low frequencies, so it actually functions as a vented box as well. As for lining the ducts, don't. Just line the interior of the cab. Lining the ducts wouldn't bother anything, but it also wouldn't help, so it's not worth doing.

craig.p · #16 05-21-2010, 07:50 AM

Bill, the other thing I recall about mine was that the baffle board was angled, almost as if Sunn were trying to make the baffle board itself the "horn" mouth. I'd never seen anything like it at the time.

**IvanMike** · #17 05-21-2010, 08:13 AM

It all depends on how cold it is where you are and if the drivers are complaining about it. You could improve the energy star rating of the cab with insulation and cut down on your heating costs...................

Ok, I try to limit myself to one idiotic post per month, couldn't resist. I'm surprised they didn't use any batting at all. Mostly.

craig.p · #18 05-21-2010, 09:41 AM

Just found this http://i53.photobucket.com/albums/g6..._004-small.jpg via a pointer in the archives. So now I know mine was NOT an RH.

Going through the old Sunn stuff in photobucket was like a trip back in time.

billfitzmaurice · #19 05-21-2010, 11:17 AM

Quote:

Originally Posted by craig.p

Just found this http://i53.photobucket.com/albums/g6..._004-small.jpg via a pointer in the archives. So now I know mine was NOT an RH.

Going through the old Sunn stuff in photobucket was like a trip back in time.

That is a front loaded folded horn. Since it's a full range cab the driver chamber should have been lined.

johnk_10 · #20 05-21-2010, 11:45 AM

i have the older Sunn 2x15 cab. its the one with the vent in the center, and it has the fiberglass insulation (damping) in it on all of the sides and back panel. IMO, this cab sounds awesome with the two JBL K140's that are in it.