Bi-amping sda 2.1

motorstereo

Finally got finished my total remodeling project due to the size of the 2.1,s. Extended the wall that they sit against by 15" more and wired up 2 dedicated circuits so each amp has it's own line. I have them bi-amped now with an adcom gfa 555 running the bottoms and a proton d1200 running the tops. I didn't think that these big polks could possibly sound any better than when I had them running only on the the adcom but they really came alive now after the bi-amp. I'm relistening now to most of my familiar recordings as I can hear things now that I didn't know where there before. Next step is to make a bass brace. I can't imagine this helping out anymore and I hate to attach a turnbuckle to my new wall but I'm going to give this a shot to. Been a long week getting this total new set up completed just for these monsters but after hearing the way it sounds now it was worth every bit of aggravation.

BobMcG

Sounds like a job well done. Congrats and enjoy.:)

dorokusai

The new setup sounds neat.

You could use spikes in lieu of a "bass brace" wall attachment.

motorstereo

Dorokusai; Right now I have felt pads on the adjusters on the bottoms of the speakers. With all the moving around I didn't want to destroy my floor and have another project as well. I'd kinda like to keep them on there as you never know; sometimes things have to be moved. Maybe spikes would be the way to go I hadn't thought of that. Anybody ever a+b the spikes and the bass brace? I'm also running a mx200 sub so monster bass isn't an issue. I would like to extract every bit of sound these speakers have to offer though. Thanks for the kind words guys. Yes I am enjoying these great speakers.

schwarcw

I haven't done the A/B test. In the owner's manual, Polk doesn't advise doing both. They claim the speaker needs to move a little.

motorstereo

That's nice to know that I don't need to do both. I didn't see that in the online offering of the sda manual. I've emailed polk twice asking to purchase a manual since my printer is down right now. I've gotten no response from them. Having thought about it most of the day I'm leaning towards the bass brace against the wall as it could be removed if for some reason I have to move the speakers. Spikes would probably raise hell with my painted floor.

F1nut

Don't email, CALL.

Polk recommends the bass brace over spikes due to the height of the cabinets. The bass brace helps prevent movement caused by all those mid drivers pumping away.

dorokusai

A pair of Carver Amazing w/ 8 12" woofers never moved around on spikes in my house....if anything it's a safety thing ONLY because of height, not because of bass, that's just....well, beyond my scope of belief.

SDA's are definetly top heavy, and on plush pile carpet, sans spikes or brace...I agree, they should certainly be a concern.

You should call, not email, as my esteemed local Polkie has suggested.

800-377-7655

F1nut

Hey, that's what Matt Polk told me. I figure he would know best.

A common tweak with the Amazings is to add a couple of cement blocks on top of the base to help anchor them to the floor, but that didn't come from Bob Carver that I know of.

motorstereo

Hey guys I appreciate all the responses. I'll have to give Polk a call. I'm a member of ak also and I'm not used to getting answers to my questions. Irks me when I ask a normal question and get no responses as some other newbies at that site do. But a guy with many posts can ask for "bathroom system recomendations" and get 4 pages of responses. This is a great forum and again thanks for the help.

BobMcG

F1nut wrote:

A common tweak with the Amazings is to add a couple of cement blocks on top of the base to help anchor them to the floor

Yup. I have two 7.5 lb steel weight plates on each of my bases. Works quite well.

SRS series: I don't believe there is an acoustical reason for not using the spikes with the Bass Brace. I think it's only an ease of movment reason. The SDAs will benifit from using the spikes in the same manor as other speakers do. The Big SRS family members are tall and top heavy and could stand to be anchored to prevent movement. Thus the Bass Brace.
The only reason I can see for not recommending the use of both at the same time is that you have to deal with spikes and the potential for floor damage while getting the cabinet lined up (moved) for the brace. Which is probably easier than locking the cabinet to the wall with the brace and then getting the spikes in place under them. (I can see people now, swearing at Polk and their big speakers after scatching the piss out of their floors.) That's the order I've always set my with. Yeah, they're a bit on the heavy side but manageable. I've always used both spikes and brace for the benfits both have to offer.

motorstereo

I finally finished my rainy day project. I installed the bass brace on my 2.3s. Pretty straight forward easy project and it has them mounted about 8" away from the wall. I really didn't notice a difference in the quality of bass though like I was hoping to. Yeah right like they don't put out enough bass. I like the bass on the sda's better than my mk200 with 2 12" drivers in push pull. Anyway now I have another problem. Apparently my wall isn't as stout as it could be and the bass transmits through the bass brace into the wall and ends up as a howl in my tt at loud volumes. I tried damping the quarter inch rod with some wire wrap but that didn't seem to help. Anyone have any ideas? I really don't want to get into more tt isolation like spikes or anything exotic but I really would like to stop that annoying howl. Thanks; Brian

F1nut

I prefer mine 5.5" from the wall. As for your TT, better isolation is the only answer.

Tour2ma

Agree... Is the TT on a wall shelf?

motorstereo

Yes unfortunately the turntable does sit on a wall shelf. I was hoping for a magical easy solution but in reality I knew it meant more isolation. Looks like I have yet another rainy day project. F1nut; you say you like yours 5.5" out from the wall. Before I go through the hassle of moving them closer what could I expect in the way of improvement when I do? I did some critical low level listening last night and I swear they seem more detailed now. Don't know if it's me knowing what I did expecting an improvement but they sure do sound sweet. Hope that makes sense.

Tour2ma

Doesn't seem right to me, but you seem to be indicating that the TT had no feedback issues before adding the bass brace. If so, then so removing the brace, and going with floor spikes, would seem to be the simplest solution. Otherwise you're looking at a floor stand, marble top, etc. for the TT.

Reason I said it doesn't seem right is that wall shelves are notorious for gathering acoustical energy and feeding it to the TT base.

What TT do you have?

motorstereo

I have a pl 560 pioneer table with a new shure m97xe cart. I have rubber balls cut in half for isolation. The base shelf that it sits on is quite substantial. It's an 8' formica countertop with 2 audio racks underneath for support and it's also attached to the offending wall. No problems at all till I connected the bass brace. I've decided I'm not going to go with floor spikes on the 2.3's as I feel the urge to move things around sometimes and I can see floor damage approaching. Having listened to the 2.3's with the brace connected I've decided that it's staying also as there is an improvement in sound quality. That leaves me with tweaking for more isolation and perhaps reinforcing this wall. I've also been thinking of doing some damping on the wall also. I'm real close to audio nirvana now just a few tweaks here and there and I'll arrive I just know I will.

Tour2ma

Gotcha... Although spikes used with little disks on bare floors have come into vogue, their original intent was for use on carpet.

Couple other thoughts/ questions...

I'm surprised that the regular feet don't anchor them solidly enough. Mine have been on them on bare flooring for the past 14 years now and no lack of bass here. Is your listening room on the ground floor? Once the 1.2's were situated, did you remove the felt pads you were using to protect the floor?

On the TT... Is it really necessary to have the shelf connected to the wall?

motorstereo

Yes I'm on the ground floor. It's a very substantial wood floor. No footfalls can be heard unless it's a dinosaur type footstomp. Yes I do still have the felt pads on the bottoms of the adjusters. I had thought about removing them but it seems I'm always moving equipment around for one reason or another and I wanted to play it safe. Unfortunately I do have to keep the shelf connected to the wall. I'm really happy with the way things are working right now except for the howl of the tt at foolishly high volumes. At sane volumes there's no problem so I'll probably just do a little bit more tt isolation and I have a few ideas about a well placed angle brace or 2 to give the wall a bit more immobility. If that doesn't work I'm thinking that's a good reason maybe for a tt upgrade.

Tour2ma

LOL... any excuse is a good one for upgrading.

Just for grins, why not try removing the bass brace and the pads. You can leave the 1.2's be for an hour or so can't you? Hell, even I can do that and I'm a speaker nudging SOB.