Opinions wanted-which sub with SDA-1As?

94Cobra

Please provide some feedback on which subs sound good with the SDA-1As. My combo is in my signature. I love the sound of my SDAs and am not ready to get rid of them. I only want to get a sub for movies and don't want the sub to become overpowering when I listen to music. Any tips on how to hook up the sub and what crossover settings work best would be appreciated. I do not have the interconnect cable installed. I also do not have a center channel speaker installed. Thanks.

Dennis Gardner

SDA without the cable is liking running a V8 on 4 spark plugs........onyour sub question, I would suggest anything from SVS, HSU, or maybe from Velodyne.

The trick for using the sub for music with towers as large as yours is to cross it over at 60 hz or even lower.

F1nut

Dennis Gardner wrote:

SDA without the cable is liking running a V8 on 4 spark plugs.........

Exactly! You're only using half of the drivers and not getting anywhere near the bass you would if you used the cable. You may find you won't need a sub.

amulford

Yeah, what he said^^^

94Cobra

Thanks for the advice. I will hook up the interconnect and see how much bass it adds. My only complaint with my Polks is that they don't produce much bass at low listening levels, where I do most of my listening. This was true even when I had the interconnect installed. I have heard my Polks are inefficient speakers since they require more current to drive them, which may explain why they don't start sounding great until I reach louder db levels. Is this a myth or fact? Are there any upgrades to the crossovers, drivers, or the terminal connectors that I can do? I still have all of the original drivers that came with the speakers when I bought them new in 1986. I noticed that I don't have gold terminal connectors. By the way, do you own a sub with your Polks?

heiney9

94Cobra wrote:

Thanks for the advice. I will hook up the interconnect and see how much bass it adds. My only complaint with my Polks is that they don't produce much bass at low listening levels, where I do most of my listening. This was true even when I had the interconnect installed. I have heard my Polks are inefficient speakers since they require more current to drive them, which may explain why they don't start sounding great until I reach louder db levels. Is this a myth or fact? Are there any upgrades to the crossovers, drivers, or the terminal connectors that I can do? I still have all of the original drivers that came with the speakers when I bought them new in 1986. I noticed that I don't have gold terminal connectors. By the way, do you own a sub with your Polks?

What size is your listening room and how far away do you sit to listen? These two factors have a big impact on low level listening as the the larger your room and the farther away you sit the more juice (volume) is needed for low level resolution. I've never had that issue with Polks but I have a pretty intimate listening environment.

H9

94Cobra

My room size is 27 x 11'6". I sit approximately 8 feet away from the speakers. The room is carpeted and I attached a picture.

F1nut

SDA's are not really inefficient speakers, yours are rated at 95dB. Shouldn't take much to get them moving. Crossover upgrades will help with bass response as will room placement. The closer to the back wall they are, the more bass you get. I don't use a sub, but mine are bigger and used only for 2 channel. Do you have them spiked? If not, that will help too.

danger boy

because of space limitations I can only use my SDA's in a 2 channel system only. I don't know how well they would work in a surround home theater system.

I would think they would be hard to dial in for a home theater. I also find that source and software play a part in how much bass the SDA's produce. I use two different NAD CD players.. and one produces more bass then the other one.. from the same company. just built in different years.

I'm interested in hearing SDA's with a sub. Just to fill in and give that extra oomph.

94Cobra

Thanks again for all the info. I had no idea there were this many vintage Polk fans - it is great to see. Does anyone have a parts list/instructions for how to do the crossover upgrades on the SDA-1As? Does the crossover come out thru the opening of the passive radiator? I just spoke to a Polk rep and they recommend the RD0194-1 tweeter upgrade. That would cost me $200 once I reconnect my interconnect cable. Based on what I have read, the tweeter upgrade is a noticeable improvement. The Polk rep also recommends that I replace the .95amp poly switches that provide tweeter blowout protection. Since the board has to come out to do the poly switches, it might make sense to do the other crossover upgrades at the same time. Thoughts.

F1nut

I can get that info to you a little later.

Refefer

heiney9 wrote:

These two factors have a big impact on low level listening as the the larger your room and the farther away you sit the more juice (volume) is needed for low level resolution.

It should be noted that this is true for any speaker, not just the polks. The Rotel should be providing plenty of umph for your SDA's, but you do need to have the interconnect cable attached to really hear/feel the dynamics.

I run a pair of 1B's and mine dig down to a little under 20hz with no real strain at low levels.

BlueMDPicker

I've used a Polk PSW-650 (crossed at 80 hz) with a variety of vintage Polks, for music only, and it's an excellent combination. I think the sub run at speaker level imparts more of the sound quality of the rest of the components. That confirguration is problematic with the SDAs common grounding requirements (unless you can safely strap the ground of your amp and sub amp), so line level would be the path of least resistance.

By all means follow the good advice here regarding utilizing the SDA interconnect. But, for movies, I'd want the extra LF extension a sub provides as well.

Good luck, and welcome to the forum!

F1nut

Parts list to do both speakers.

Caps:
(2) 0.5uF
(4) 12uF
(4) 27uF

Resistors:
(4) 3.5 ohm
(4) 2.7 ohm

(4) Polyswitches - call Polk

(6) 750pF Silver Mica caps - you really don't need these, IMO if you install film and foil caps, but it's up to you.

Cap choices are plentiful. Solen makes a good inexpensive cap. Sonicap's are my choice, but cost more. Any film and foil cap will be better than the stock ones. For resistors you want Mills Wire-wound (5 watt).

You quessed right, take out the PR's to remove the crossovers and at the bare minimum, get the new tweeters.



Edit: I agree with Blue, for HT you'll probably want a sub.

94Cobra

Thanks for the info. I appreciate the help.