What did you do to your stereo rig today?

gp4jesus

Gardenstater wrote: »

I'm gonna need another piece [of BH] from you so I can put some in the back of the enclosure behind my driver in my Martin Logan Dynamo Sub.

How would that affect the your ML sub’s FR?

motorstereo

I've also wondered about putting my left over bh5 in my sub.......anyone know if it's a good idea or should I leave well enough alone?

Gardenstater

gp4jesus wrote: »

Gardenstater wrote: »

I'm gonna need another piece [of BH] from you so I can put some in the back of the enclosure behind my driver in my Martin Logan Dynamo Sub.

How would that affect the your ML sub’s FR?

I don't know. I think that it will have the effect of making the enclosure size somewhat larger. I don't know how much larger based upon size of BH5 piece. The EQ section of the circuitry inside is designed for the sub as is, not modified, of course.

I think I need to start small. I would hope that by attenuating some of the back wave reflection, it will make the sound more clean. Also, the BH5 should reduce some of the panel resonance on any panel it is applied to.

I would also appreciate any input from DIY speaker builders.

Gardenstater

motorstereo wrote: »

I've also wondered about putting my left over bh5 in my sub.......anyone know if it's a good idea or should I leave well enough alone?

You still haven't given us your listening impressions on your 1.2tl's !!!

motorstereo

Gardenstater wrote: »

motorstereo wrote: »

I've also wondered about putting my left over bh5 in my sub.......anyone know if it's a good idea or should I leave well enough alone?

You still haven't given us your listening impressions on your 1.2tl's !!!

Woops sorry bout that. Ok here's what I've noticed so far in my few hours of listening. To start with there's slightly better bass and slightly clearer vocals. Those 2 areas are very subtle improvements and it does take some critical listening to notice the change. The biggest change I've noticed and is impossible to overlook is the center image is now more solid and pronounced. I had always thought the 1.2tl's center imaging was a weak spot compared to some of my other speakers. That is no longer the case. Thankfully this increased center imaging does not come at the cost of losing any of the wide and deep sda soundstage. I have not noticed any change in the depth or width of the soundstage.

I'm also wondering if some of the improvements may have come from breaking and re-making 16 speaker connections that haven't been touched since 2012. At any rate I'm pleased with the improvements and recommend this easy to do mod.

Gardenstater

Well that's terrific! I believe your install was about 40% less BH5 surface area per MW driver than mine. Perhaps it was more subtle in your case due to that, whereas it was in your face instantly noticeable in my particular situation. I don't think mine is overdone or too sterile and I'm really happy with it. Everything is just clearer, and I also noticed a better center image where there is more air to the sound and the acoustics of the recording venue are more apparent, making everything sound more live.

invalid

I think that it will have the effect of making the enclosure size somewhat larger. I don't know how much larger based upon size of BH5 piece.



Black hole 5 does not make the cabinet seem larger, that's what polyfill is for. Black hole five is to cut down the reflection inside the cabinet so you have a cleaner sound.

Gardenstater

motorstereo - Did you read DarqueKnight's thread on his BH5 1.2tl install? He used more material; strips on the side walls and behind the tweeters.

https://forum.polkaudio.com/discussion/148198/blackhole-5-damping-material-in-the-sda-srs-1-2tl

invalid - you don't think that the speed of sound would be reduced when travelling through that outer layer of open cell foam until it reaches the barrier layer of polymer that isolates the inner damping mat'l + foam from the outer? That layer is about 1" thick. If so, then the effective cabinet volume should increase by some small amount. At least that's my understanding.

Edit to add - However, there is about 1/4" of reduced cabinet volume due to the location of that isolation layer. I wonder if it balances out at no effective volume change?

pitdogg2

There is no back wave from tweeters. Yes I also ran a 4" wide piece behind the woofers only and the same length of the woofers on the sides 3 inches wide. I covered non of the factory standing wave cuts. There's minimal if any gain to be had behind the tweeters.

SRS 2.3tl

Gardenstater

I assumed that DarqueKnight knew there was no backwave from the tweeters and that the reason he put some material there was that it was just a suitable place to put some more in, absorbing more reflected and standing waves in such a large cabinet volume as the 1.2tl.

gp4jesus

motorstereo wrote: »

I've also wondered about putting my left over bh5 in my sub.......anyone know if it's a good idea or should I leave well enough alone?

I thought about it. We know BH5 would help w/resonances but I’m guessing the BH5 excels at maybe 500-1K hz on up - little if any in the lowest octaves.

However consider this non-comital way to try it. Do a little listening to just the sub. Casually tape a piece to rear wall. And, well... you know the rest.

Let us know. Tony

Gardenstater

Tony - I guess brilliant minds think alike I was thinking just the same and that maybe a couple strips of double sided carpet tape would work well. Of course, the BH5 won't have its full effect of reducing the vibrations of the panel it is taped to, as it would if it was properly bonded with its PSA, and when removing it the protective paper may be taken off at the same time. No biggie.

gp4jesus

Gardenstater wrote: »

Tony - I guess brilliant minds think alike I was thinking just the same and that maybe a couple strips of double sided carpet tape would work well. Of course, the BH5 won't have its full effect of reducing the vibrations of the panel it is taped to, as it would if it was properly bonded with its PSA, and when removing it the protective paper may be taken off at the same time. No biggie.

Thanks George - yes we do! I believe he could confirm either way if BH5 affects bass response the way it affects mids and above - since this is an FR-only experiment, I doubt he will hear a diff.

If I had piece of BH about a foot square I’d give it a go though my subs come up a smidge short below 30hz

Curious... Tony

Gardenstater

Interesting youtube video.....Does Polyfill Make a Box Bigger? - Tested and Revealed

https://www.youtube.com/watch?v=INM0g1JeMLY

One could do the same experiment with BH5 carpet taped inside of a subwoofer enclosure.

I have modified my Martin Logan Dynamo so that I have the option of placing the circuit board outside of the enclosure and I could actually stuff it completely full with Polyfill and/or BH5 on all the walls except the baffle. I'd have to get the measurement equipment of course.

motorstereo

motorstereo - Did you read DarqueKnight's thread on his BH5 1.2tl install? He used more material; strips on the side walls and behind the tweeters.

https://forum.polkaudio.com/discussion/148198/blackhole-5-damping-material-in-the-sda-srs-1-2tl

Thanks and yes I did read that. The jury is still out whether or not I'm going to do the side wall strips. At some point I probably will and then I'll have a good reference point of how they sound with just the backs done. There's no backwave behind the tweeters so no I don't plan on treating that area. .

Gardenstater

OK cool. Looking forward to your further impressions. Not to be a wiseguy but there's no "backwave" at the sides either. I think it's more a matter of having the BH5 in the vicinity of the drivers because every surface of the back of the cone becomes a point source for a sound wave, in other words there are sound waves radiating out in all directions and bouncing all over the place within the cabinets and that can cause interference with the proper primary motion of the cones. I think the other key is amount of BH5 relative to total cabinet volume, along with keeping the area around the passive free of it. Just my 2c.

Mike Reeter

Finished up some stands for a recently acquired pair of Quicksilver Mono 120 Amps.

dkfreebird

Picked this up to give it a spin.

gp4jesus

dkfreebird wrote: »

Picked this up to give it a spin.

looks like a preamplifier?

dkfreebird

It's an Integrated amp.

Tony M

I just looked up it's specs and it seems very well made .

It's supposed to drive all speakers with ease. Sounds like a winner to me.

let us know later on.

dkfreebird

Will do,once I spend some more time with it.But I can say right now this is the best amp I've had in my system so far and it has detail in spades. It doesn't break a sweat running the 1.2tl's.

marvda1

@dkfreebird sure you don't want to try a norma in there?

dkfreebird

@marvda1 I'd love to. Heard it at Skips.But at the stupid price I got this at it was a no brainer to me. Norma is a little out of my price range at this point. But....You never know.

hochpt21

I swapped my 2a’s back in for my 703’s in the man cave. It’s been awhile. Boy I sure do miss the SDA sound!!

nooshinjohn

Man cave, huh.... did the wife pick that color?

hochpt21

nooshinjohn wrote: »

Man cave, huh.... did the wife pick that color?

Lol, no I did. Got the color code off a former member a few years back who had it for his room. It’s more burnt orange than it looks.

I like the energy.

Tony M

I always liked how color on walls can affect our mood.

Tony M

gp4jesus

Gardenstater wrote: »

Interesting youtube video.....Does Polyfill Make a Box Bigger? - Tested and Revealed

https://www.youtube.com/watch?v=INM0g1JeMLY

In the motorhead world: there’s no replacement for displacement.

I’m a bit disappointed Polyfill seems to make less of a difference than I was lead to believe. YMMV w/the driver higher Qts versus lower Qts. Could help some w/BSC for a mid-woofer or fudge if the closure is a slightly undersized.