some questions on Black Hole-5

leftwinger57

A few days ago I saw an add in my local C/L for sheets of BH-5 @ $20 per sheet or $75 for all of them. Now the ?s, first off is that a good price for what I remember as complete sheets ,size truely unknown.2. is one sheet enough to do 2 SDA 2bs.3. How far up do you place this stuff or only around the passive cavity.4.How much overall betterment is actually adding this stuff w/Ex Dynamatting already done 5.Knowing how cheap/poor I am would the egg crate packing style of foam insulation be a decent replacement because I can get that stuff for free I relise the density would be different but would it be noticeable? Thanks ...Lew

I went back and found the add if it helps...

http://cnj.craigslist.org/ele/4080706974.html

drumminman

leftwinger57 wrote: »

A few days ago I saw an add in my local C/L for sheets of BH-5 @ $20 per sheet or $75 for all of them. Now the ?s, first off is that a good price for what I remember as complete sheets ,size truely unknown.2. is one sheet enough to do 2 SDA 2bs.3. How far up do you place this stuff or only around the passive cavity.4.How much overall betterment is actually adding this stuff w/Ex Dynamatting already done 5.Knowing how cheap/poor I am would the egg crate packing style of foam insulation be a decent replacement because I can get that stuff for free I relise the density would be different but would it be noticeable? Thanks ...Lew

I went back and found the add if it helps...

http://cnj.craigslist.org/ele/4080706974.html

Don't know the exact dimensions of your speaks but you want to attach 3-4" wide strips on the inside back wall directly across from the MW's, from the top of the cabinet to the bottom of the lowest mw, but no lower. You don't want it at the level of the PR as putting it there will kill the bass.

The BH 5 you found is an OK deal as there's no shipping involved. The cost works out to 9.3 cents per sq. in vs. 10.8 cents per sq in if you buy from Sonicraft. The stuff from sonicraft comes in bigger sheets, 24 x 27, and I used about 1/2 - 2/3 in my 2.3TL's. Those cabinets are a little larger than your 2B's I think. Some folks on CP also put strips on the side walls as well.

Puttting too much in will also kill the bass as well as flatten the mid range and take the "life" out of the speakers. I would stay away from the cheap egg crate foam, as it really won't do much. BH 5 is one of the most cost effective mods.

After I did mine I did a review here: http://www.polkaudio.com/forums/showthread.php?128159-Black-Hole&highlight=drumminman


Darqueknight did a nice writeup with pics here: http://www.polkaudio.com/forums/showthread.php?148198-Blackhole-5-Damping-Material-In-The-SDA-SRS-1.2TL&highlight=drumminman+blackhole

zingo

I didn't use BlackHole, but here is placement of dampening foam in my SRS 2s, and you can see each 6 sq/in piece takes up about 2/3 of the back cabinet wall behind each midwoofer.

Toolfan66

That's a great price IMO.

leftwinger57

Ok, I already tried a mail to the guy to see if it's stiil available. Drumminman, I referd to your write up and your 2.3s after going back to the SDA handbook because the Polk naming system I just don't get but it appears your tweeter array is in between the mids on both sides. 2bs have 1 high vertically mounted per cabinet.It appears on Darqueknights write up he did go behind his tweeters on his giants. I think 1 sheet should do it if done in the strip method or just squared behind the mids.Thanks a bunch I hope this dude gets back to me.BTW by my measurement 16''' wide and aprox. 15'' to bottom of the mids.

zingo

If you have open cabinets without any internal bracing, I would place some BlackHole behind the tweeters as well, due to the face that the backwaves from the woofers will hit that area.

drumminman

leftwinger57 wrote: »

Ok, I already tried a mail to the guy to see if it's stiil available. Drumminman, I referd to your write up and your 2.3s after going back to the SDA handbook because the Polk naming system I just don't get but it appears your tweeter array is in between the mids on both sides. 2bs have 1 high vertically mounted per cabinet.It appears on Darqueknights write up he did go behind his tweeters on his giants. I think 1 sheet should do it if done in the strip method or just squared behind the mids.Thanks a bunch I hope this dude gets back to me.BTW by my measurement 16''' wide and aprox. 15'' to bottom of the mids.

I didn't have a digital camera when I did mine, but I put a strip behind each bank of MW's vertically and a horizontal one behind each tweeter connecting to the vertical strips - picture a ladder with three rungs.

leftwinger57

As well as I can remember they are wide open.Then again I really did not disturb the polyfill up on top so there might/might not be a brace somewhere.I take that back when I Liquid Nailed the seams I don't recall any internal bracing.Oh, the guy replied and said if shipped or p/ud $10 off but wants to off the entire package which I neither need or can afford. I told him I'm in the next town over and can be there w/in 20 minutes or so and want to do this.Also gave him my telco # to try to expedite this.

zingo

Go get em!

leftwinger57

Ok boys and girls the deal is done and I got all this for $18 and a 15 minute ride each way. That's not the end of the story, I've seen his adds before and it's for gear on the high end side.He has for sale a home built beautiful Redwood or Rosewwood H/t and some NAD stuff and a freaking huge Bryston 250 wpc ss amp still w/ xferable warranty for $1400. This was a cold c/l so no affiliation but anyone in central Jersey if interested pm me and I told the guy I would pass on his telco #.Presently he's out of work but his prices do seem realistic and not desperate.Thanks to you all for some more guidence along the way and maybe someday we will see/hear who has the best 2bs in Jersey, that's right it's not a competition ,it's for personal enjoyment.Oh 1 pix is quite on the blurry side and don't have the time to redo....

drumminman

Ya did good!

On3s&Z3r0s

@leftwinger57, I'm about to add some Blackhole to a set of 2B's and was wondering how you ended up placing yours in the cabinets for best effect? Did you run vertical strips all the way to the top of the cabinet on either side of that middle brace between the MWs, or did you just do squares? Anything behind the tweeter? Thanks!

Anyone else who has put Blackhole in 2Bs, any guidance is welcomed. I have a big sheet bought from Sonic Craft and actually have a studio set of 2B cabinets and a set of standard cabs, so I guess I could do some of my own experimentation, but any starting point would be appreciated.

Toolfan66

On 2B's I would cut strips 4" wide 12" long, and place them centered behind the drivers, that would be about perfect IMO..

westmassguy

Lew, I just ordered a sheet for my 2As, so will post results here. I did some final mods on my crossovers, so hopefully I won't have to open them again anytime soon.

drumminman

Toolfan66 wrote: »

On 2B's I would cut strips 4" wide 12" long, and place them centered behind the drivers, that would be about perfect IMO..

^^ ^ ^ This - I would add the strips should go only as low as the bottom of the lowest MW, not into the area behind the PR.

leftwinger57

Man you have one complicated friggin computer name. What I did was to cut strips about 4'' in width and placed them from the top of the cabinet to the bottom of the mid woofers. I was carefull w/ removing the polyfill and kept it as it was rolled up in the 1st place. You want no sound barrier at all in passive woofer cavity or it will deaden your bass response. I did this before I got Larry's rings so just a word of advise if your doing the Black Hole-5 I would do the Dynamatt and rings at the same time. The goo to the right was Liquid nails that was cleaned up.


http://s42.photobucket.com/user/leftwinger57leftwinger/media/blackhole-5010_zps8e94aee2.jpg.html

leftwinger57

Dave, I thought all your speakers were done finished and completed all to the fullest extent now your just getting around to BH-5? What's up w/ that a new set or just an overlooked mod ? Tell me about opening them up,after the air leak test I of course had to and re Armaflexed the entire right one. Now they are buttoned up tight w/ a mid woofer return of 4/5 seconds on both sides.

westmassguy

leftwinger57 wrote: »

Dave, I thought all your speakers were done finished and completed all to the fullest extent now your just getting around to BH-5? What's up w/ that a new set or just an overlooked mod ? Tell me about opening them up,after the air leak test I of course had to and re Armaflexed the entire right one. Now they are buttoned up tight w/ a mid woofer return of 4/5 seconds on both sides.

Lew, never said my 2As were completed. Like many other, I have limited discretionary income. I did the Hurricane nuts, cabinet re-sealing, Dynamating, and initial crossover upgrades 1st. I used Sonicaps for the Hi-Pass, Daytons for the Lo-Pass, and NP Electrolytics for the giant 260uf caps needed for the full Compliment Sub bass Drive Section. I saved up some more, and replaced the NP Electrolytics with some huge Dayton Caps, and did the Sub Bass Drive Inductors with Erse SuperQs. Saved a little more, and did the TL Mod, added Spikes. I've now revisited the crossovers, and replaced the Lo-Pass shunt Caps with Sonicaps, and also changed all the remaining Inductors to Jantzen Perfect Lay. Just waiting for my Blackhole5 to get here, and with luck, that will be the end of the internal upgrades. I still plan to veneer the exteriors with quarter sawn walnut.

emionence1963

westmassguy wrote: »

Lew, never said my 2As were completed. Like many other, I have limited discretionary income. I did the Hurricane nuts, cabinet re-sealing, Dynamating, and initial crossover upgrades 1st. I used Sonicaps for the Hi-Pass, Daytons for the Lo-Pass, and NP Electrolytics for the giant 260uf caps needed for the full Compliment Sub bass Drive Section. I saved up some more, and replaced the NP Electrolytics with some huge Dayton Caps, and did the Sub Bass Drive Inductors with Erse SuperQs. Saved a little more, and did the TL Mod, added Spikes. I've now revisited the crossovers, and replaced the Lo-Pass shunt Caps with Sonicaps, and also changed all the remaining Inductors to Jantzen Perfect Lay. Just waiting for my Blackhole5 to get here, and with luck, that will be the end of the internal upgrades. I still plan to veneer the exteriors with quarter sawn walnut.

Is there a write up on your modifications that you have done with pics?
Also this is the 2's you are modifying with the double tweeters at the top you are talking about correct? I have the same units and was just trying to get ideas as to were to go with future mods next.
Sorry for the off post here

westmassguy

emionence1963 wrote: »

Is there a write up on your modifications that you have done with pics?
Also this is the 2's you are modifying with the double tweeters at the top you are talking about correct? I have the same units and was just trying to get ideas as to were to go with future mods next.
Sorry for the off post here

You have the original 2nd generation 2s, Mine are the 3rd generation 2As.
Here's one post I did: http://www.polkaudio.com/forums/showthread.php?143984-My-2As-Finally-Finished...Almost
Even then I knew I wasn't finished

leftwinger57

Dave,I haven't the slightest idea of half of what your talking about, way over my head w/ the inductors and stuff. So your just like me and many many others that has to do it piecmeal do to lack o' funds. I was thinking there should be a way to remove the passives much easier than it is to do now. Like that space between the mids.Just a tad more routing. I tried pushing them out from the open mid holes but that idea did not work. Some channels at every 1/4 clock position to get a tool in there to lift them out that's what I say. Good luck the BH-5 with out a doubt takes away some or all of that hollow type of sound, it kinda freaked me out at 1st it was that dramatic and I wasn't sure it worked right. Like the polyfill never exsisted. I just had to get used to the new sound.

westmassguy

leftwinger57 wrote: »

Dave,I haven't the slightest idea of half of what your talking about, way over my head w/ the inductors and stuff. So your just like me and many many others that has to do it piecmeal do to lack o' funds. I was thinking there should be a way to remove the passives much easier than it is to do now. Like that space between the mids.Just a tad more routing. I tried pushing them out from the open mid holes but that idea did not work. Some channels at every 1/4 clock position to get a tool in there to lift them out that's what I say. Good luck the BH-5 with out a doubt takes away some or all of that hollow type of sound, it kinda freaked me out at 1st it was that dramatic and I wasn't sure it worked right. Like the polyfill never exsisted. I just had to get used to the new sound.

I'm sure Polk didn't intend for its customers to be pulling their speaker apart. I looking forward to trying the Backhole5 too.

On3s&Z3r0s

leftwinger57 wrote: »

Man you have one complicated friggin computer name. What I did was to cut strips about 4'' in width and placed them from the top of the cabinet to the bottom of the mid woofers

I hear you about the name... that was a poor choice. Was using that in another spot and thought I'd keep it but every time I have to log in on a different computer I regret it. Oops. Anyway, it looks from the pics like you went with a total of four strips each 4" in width? I couldn't tell from Larry's earlier post if his method was two strips or four. If I get ambitious I might try two first and then four using just the adhesive backing before I glue them down permanently. Thanks for the advice!