Black Hole

[drumminman]

Over the Christmas break I had time to open my 2.3TL?s and perform two mods I had wanted to do for some time: seal the cabinets and install Black Hole damping sheets.

The sealant I used is by Loctite and is listed as low VOC?s (< 0.5%) with no respiratory warnings on the label. It?s actually sold as construction adhesive. Can?t remember the name now, but when I get home I?ll have a look and post it. I bought three tubes at Lowes and used less than one.

Anyway the reason I did this is that with all the mods I?ve done, the speaks are a little bass shy. When doing the PR push test I had noticed that the MW?s recede to the half way point almost immediately (~ 1 sec). So I proceeded to remove all MW?s and both PR?s, and the batting, and carefully set aside the internal wiring. I had a full size caulking gun, which was tough to maneuver inside the cabinet. Where I couldn?t get it to go I used the ?ol finger method. The stuff dries clear, and has absolutely no odor! The front baffle was completely sealed with glue so I only needed to do the side panels and top and bottom caps.

Then it was on to the Black Hole. I read of TF66?s and others experience with using too much of this stuff. Apparently too much kills the sound, makes it flat and dull. I used a utility knife and heavy duty scissors to cut four 3? wide x 27? long strips, which I installed vertically on the inside back panel directly behind each bank of MW?s. Then I installed six 3.5? wide strips behind each tweeter; these were long enough to form a ?bridge? between the two verticals. It?s pretty easy to install as it has a strong PSA (pressure sensitive adhesive) that really grabbed. I did clean the back panel with a damp cloth just to be sure there wasn?t any dust or loose particles that might affect the bond. I used a little less than one sheet, which is good sense Black Hole is a little pricey, even with the 20% discount I got during Sonicraft?s sale.

Then I reinstalled the batting, reconnected all the wiring, and buttoned both speakers up. Another push test revealed a slower return to the midway point, around 2.5-3 seconds. Progress! Last night was the first time I had an opportunity to listen.

Front end includes Magnavox CDP, Peter Daniel DAC (both digital units fed by balanced power transformer), Odyssey Candela linestage w/ RCA clear tops fed by 1 KVA isolation transformer, Odyssey Stratos w/ Cap Upgrade fed by 1.5 KVA balanced power transformer, 12? sealed sub fed by 1 KVA line conditioner. Cables mostly DIY. You can see the previous mods I?ve done in my sig. Before these latest two I was very happy with the sound I was getting: nice SDA soundstage, smooth top to bottom, good transient response, good bass quality if not quantity. The latter I'm pretty sure is due to less than stellar placement, which I can?t do anything about unfortunately.

I?ll say right off that I was pretty surprised at what I heard. First I put on one of my favorites, Susan Tedeschi. This is a compilation of some of her best stuff, and most of the tunes are well recorded. Her band has both a piano and Hammond B3, background singers, a great bass player, drums, guitar. Next up was Miranda Lambert?s ?Crazy Ex-girlfriend?, then Best of Talking Heads, and finally Chicago?s debut album (still my favorite). The changes I heard were present across all these albums.

I never thought of these speakers as sounding congested, but the sound stage has opened up front to back and side to side. Each instrument is more clearly heard at its own particular volume level and in its place. It?s fascinating on the ST album to hear the organ move to the front playing lead or heavy rhythm, and recede to the background playing flourishes. Transients are improved with ride cymbals a little easier to hear. Female vocals sound a little more natural; a little chestiness I hadn?t noticed before is gone. The speakers, while sounding smoother also have more slam, more dynamic punch. I haven?t noticed a change in bass output. It does a fine job until that point, but the speaks are rated for 750 wpc, and it?s somewhere around 150-180 wpc. Now what I?m thinking is that the sound wave from the MW?s was bouncing off the back wall (before BH) and returning to hit the rear of the cones causing breakup and loss of clarity. I never thought the 2.3TL's lacked any of the qualities I heard last night, they are now enhanced.

I?m running out of descriptions here, but to sum it up I would say the BH is absolutely worthwhile. Sealing the cabs, don?t know since I did both of these together. I would rank this as one of the top tweaks I?ve performed on the speakers, especially for the cost.

[quadzilla]

Sounds like basically the way I did mine. It's a very worthwhile mod.

[drumminman]

Damn cut 'n paste ! Part of the review doesn't make sense - I wrote it in MS Word and then c/p to the forum. Here's what it should have said starting about midway through the nes to last paragraph:

I haven't noticed a change in bass output. The speakers, while sounding smoother have more slam, more dynamic punch. And here?s the really interesting part: I had the volume up louder than I ever have. I had always assumed that when I turned it up past a certain point the amp was starting to run out of gas. It does a fine job, but the speaks are rated for 750 wpc, and it?s somewhere around 150-180. Now what I?m thinking is that the sound wave from the MW?s was bouncing off the back wall and coming back and hitting the rear of the cones causing some breakup and the speakers to sound less than their best.

[Conradicles]

Nice I may try this on my Monitor 7A's. Thanks!

[Face]

The mids should be much more coherent with BH in place behind them.

[Toolfan66]

For this type of application Sonic Barrier works just as good and save you a lot of coin.

[VR3]

I would say No Rez would be a lower cost alternative and it is a good bit better than Sonic Barrier, IMO - I cant SB to stick to anything without help

[Toolfan66]

I have yet to try No-Rez

[Face]

Black Hole and No-Res are both excellent, Sonic Barrier isn't as good as either one.

[VR3]

Yeah I am not a huge fan of Sonic Barrier...

From my research it seems BH is better for subs and NR for mids/highs

[drumminman]

Black Hole and No-Res are both excellent, Sonic Barrier isn't as good as either one.

Haven't tried SB or NR, but I have to agree the BH works amazingly well in this application. Can't recommend this tweak highly enough. Did more listening last night and the effect is stunning. Who'd a thunk???? Have enough left to do my RTA 12C's.

Left to my own devices I probably would have used too much. Happy to stand on the shoulders of those who came before

[Toolfan66]

I agree with you Mike but with just putting strips behind the mids I noticed no sonic improvement between the two.

[drumminman]

The name of the sealant I used is Loctite Power Grab Heavy Duty Exterior Construction Adhesive.

[F1nut]

Nice write up Fred, thanks!

[schwarcw]

Any pictures or a schematic of where you placed this material inside the 2.3's? I have a pair and i am interested to learn more!

[drumminman]

Any pictures or a schematic of where you placed this material inside the 2.3's? I have a pair and i am interested to learn more!

Sorry, no pics. The long strips of BH are placed vertically on the inside back wall directly opposite the bank of two and bank of 4 MW's in each cabinet. Then I cut 3.5" strips (three for each cab.) and placed them horizontally opposite the tweeters also on the back wall. These "connected" the two vertical strips so it looks like a ladder.

Hope this helps.

[PolkMaster1]

I applied BH5 to the back of the midrange and tweeter section in my 1.2TLs a year ago. For those who are thinking of doing this in their SDAs, keep the BH5 away from the PR section.

Highly recommended.

[PolkMaster1]

I?m running out of descriptions here, but to sum it up I would say the BH is absolutely worthwhile. Sealing the cabs, don?t know since I did both of these together. I would rank this as one of the top tweaks I?ve performed on the speakers, especially for the cost.

When you sealed your cabinets, which I assume you mean you sealed the drivers and tweeters, it added the slam impact you are describing. I sealed my drivers, tweeters, and PR with mortite. It is a very inexpensive investment, and has a high ROI, adding to the slam and definition you are describing. If you get a chance, add dynamat to the baskets on your MW and PR. This will dampen renosance on your baskets. This is another low-cost tweak you can perform on your SDA-SRS'.

PM1

[drumminman]

When you sealed your cabinets, which I assume you mean you sealed the drivers and tweeters, it added the slam impact you are describing. I sealed my drivers, tweeters, and PR with mortite. It is a very inexpensive investment, and has a high ROI, adding to the slam and definition you are describing. If you get a chance, add dynamat to the baskets on your MW and PR. This will dampen renosance on your baskets. This is another low-cost tweak you can perform on your SDA-SRS'.

PM1

Definitely do not put BH below the MW's!

Also, sealing the cabinets meant running a bead of the construction adhesive wherever two panels meet and there's no visible hot glue. Different than using mortite on the drivers, though I did something similar a while back except I replaced the mortite with Armaflex.

[PolkMaster1]

Also, sealing the cabinets meant running a bead of the construction adhesive wherever two panels meet and there's no visible hot glue. Different than using mortite on the drivers, though I did something similar a while back except I replaced the mortite with Armaflex.

Ahh - thanks for the clarification. I would do that myself, which sounds like it would be worthwhile to do - but I would like to replace the wood paneling one day.

[jmitchnh]

This may be a really dumb question, but when you install the BH5 I'm assuming you discard the factory fiber fill ?

[Toolfan66]

This may be a really dumb question, but when you install the BH5 I'm assuming you discard the factory fiber fill ?

I kept mine in.

[evhudsons]

Yes keep the fill in the speaker.

[drumminman]

This may be a really dumb question, but when you install the BH5 I'm assuming you discard the factory fiber fill ?

I kept mine in. The effect of the BH (and fiberfill to a lesser extent) is that it prevents the internal soundwave from bouncing off the back wall and returning to hit the back of the MW's. It makes the cabinet "seem bigger" than it is.

[Toolfan66]

I pulled out the sonic barrier this last week and I put 4" strips of BH5 in its place but this time I added 2" strips on the sides of the cabinets with great results and I will eat my words the BH5 is better on all aspects to the SB...

[evhudsons]

I wonder if I have my norez installed incorrectly. I have the much smaller crs+ with about the same size pieces attached to the top, bottom and sides (one piece each) but not against the back. The passive and the crossover takes up most of that space, but from the description maybe that's where I should try to put it, and maybe even less of it. They are more like 3 inch squares rather than strips. I apologize for interjecting a crs question on your thread, but I would like to fully understand the concept and your thread is making it much clearer.

[thsmith]

I ordered No-Rez last week, glad to see it is a worth wild tweak. Had not thought of sealing the cabinet like OP but I will add that to the list. Once the new gaskets get here I will probably do all at once.

[Toolfan66]

I wonder if I have my norez installed incorrectly. I have the much smaller crs+ with about the same size pieces attached to the top, bottom and sides (one piece each) but not against the back. The passive and the crossover takes up most of that space, but from the description maybe that's where I should try to put it, and maybe even less of it. They are more like 3 inch squares rather than strips. I apologize for interjecting a crs question on your thread, but I would like to fully understand the concept and your thread is making it much clearer.

I have mine on the side walls of my CRS's as well. There really is no room on the back wall.

[headrott]

Bump of an older thread..... But, wanted to ask you Fred if you only bouoght one sheet of BH5 to use on your 2.3TL's? I am definately interested in doing this tweak as I have noticed some recordings are very "congested" sounding. With the mids and upper bass really blending and making the audio sound unbalanced and well, "congested". Some recordings, not so much. I listed to the MF SACD of Stevie Ray Vaughn's "The Sky Is Crying" and it doesn't have this congestion as much. But, listening to the MF Gold CD of Beck's "Sea Change", the mids and bass are definately congested.

[drumminman]

But, wanted to ask you Fred if you only bouoght one sheet of BH5 to use on your 2.3TL's?


Yep, just one sheet if you apply in strips as described in my OP above. I had enough leftover to do my RTA 12C's too. From my experience it may well be all you need to clean up the congestion. I was surprised at how well it worked - cheap and effective tweak.