No need to IC if bi-amp the SDA

fredv

Here is what I found from:
http://www.polkaudio.com/home/products.php?category=3&speaker=275&vintage=1

For even greater dynamic range and lower distortion, the SRS loudspeakers may be connected for Bi-Amplification using the two sets of inputs provided on each loudspeaker. No electronic crossover is necessary. By permitting different amplifiers to reproduce the high and low frequencies separately, the SRS loudspeakers achieve their greatest sonic potential.

Am I impterpreting the above correctly? If the SRS are bi-amp, then there is no need to use interconnect cable???

-fredv-

RuSsMaN

Where does it say ANYTHING about the interconnect cable, and not using it?

Sheesh.

danger boy

Originally posted by fredv
Am I impterpreting the above correctly? If the SRS are bi-amp, then there is no need to use interconnect cable???

-fredv-

that's just crazy talk....

SDA cable in use... gives you SDA sound
no cable.. no SDA sound.

BlueMDPicker

Come on guys, I think he's just misinterpreted the "no electronic crossover is necessary" to mean the SDA IC.

fredv

Originally posted by BlueMDPicker
Come on guys, I think he's just misinterpreted the "no electronic crossover is necessary" to mean the SDA IC.

Yeah, somehow the brain crossed wire, totally mixed up crossover and interconnect crosstalk should have gone bed and get ready for today's 2.3 trip instead of reading every SRS literature that I could find

-fredv-

danger boy

Originally posted by fredv
Yeah, somehow the brain crossed wire, totally mixed up crossover and interconnect crosstalk should have gone bed and get ready for today's 2.3 trip instead of reading every SRS literature that I could find

-fredv-

take a deep breath.. and repeat after me...

BobMcG

fred,

There are different ways to bi-amp and bi-wire and different degrees to which you can take them to achieve the cleanest or clearest signal possible to your speakers by avoiding signal interactions and disributing the demand requirements of your power source(s). Lower frequencies with their longer wave-lengths require more power to reproduce accurately than do high freqs and thus can place a greater load upon the amp.

This quote from Polk,

For even greater dynamic range and lower distortion, the SRS loudspeakers may be connected for Bi-Amplification using the two sets of inputs provided on each loudspeaker. No electronic crossover is necessary. By permitting different amplifiers to reproduce the high and low frequencies separately, the SRS loudspeakers achieve their greatest sonic potential.

is refering to what is sometimes called verticle bi-amping. Where one normal "stereo" amp is connected to the top binding posts and another is connected to the lower posts so one is in charge of reproducing the highs and the other the low frequencies. No AI-1 is required but the SDA IC still must be used in order for the SDA to work (always). This is opposed to horizontal bi-amping where one "mono" amp is responsible for each channel and requires an AI-1. It is done for the same reason (stated by Polk) that is "behind" the reason for bi-wiring your speakers with "double bi-wires" rather than a single bi-wire or no bi-wire at all. It all comes down to separating the two frequency ranges to reduce interaction and any possible related distortion.

HOWEVER: When verticle bi-amping w/o the use of an outboard electronic crossover (which as Polk states is NOT mandatory) a full range signal is being sent to the speaker by both amps at both levels. The use of a crossover would be to further separate the frequencies by sending only what is required to be used at the upper and lower levels of the speaker.

My 2.3s are being and have been for quite some time bi-amped horizontally with double bi-wires but they were vertically bi-amped w/o a crossover for probably a half year or more when I first got them nine years ago. Either way is just fine but I can make more power available to them the way they are now through bridged amps @ 750watts RMS into 8ohms and far more than that into 4ohms.


PLEASE: Anyone else is more than welcome to expand upon or make adjustments to my attempt to explain all of this.

BobMcG

fred,

I see you've posted with the others while I was typing my response so you can disregard.

Man, what a waste of time........

BlueMDPicker

Originally posted by BobMcG
Man, what a waste of time........

Not in the least, Bob. Thanks! It's bookmarked in my Polk favorites.

Mike

BobMcG

Mike,

Cool, It's nice to know all that typing might be of use or value to someone!

I hate typing!!!

madmax

The SDA's are weird. If you want to bi-amp just use two amps and don't use an outboard crossover. The bass and treble actually overlap and they seem to do better without an external crossover. Of course you have already figured out that you need the interconnect cable no matter what you do.
madmax

fredv

Originally posted by BobMcG
fred,

I see you've posted with the others while I was typing my response so you can disregard.

Man, what a waste of time........

No, not at all. I have been trying to figure out how to get the very best out of the 2.3 since the big girls (hey, people call the 1.2 big boys, these are not that much smaller, Polk brochure spec it at 155 lbs each) arrived home 4 hours ago. The information/expertise that you provided is very valuable to me. One challenging task for me is to survey my house for which room is the best fit (meaning after a major furniture shuffling). I have a few stupid newbie questions:
1. Is bi-wire the same as using the "jumpers" to connect the +ve posts and the -ve posts?
2. what is double bi-wires?
3. how much better are the 2.3 TL vs the TL, the 2 models appear to be quite different, the TL has the TL tweeters and 2 more active mid/bass drivers.

Thanks,

-fredv-

F1nut

1. You can bi-wire, you can use the jumpers with a single run and you can bi-wire and still use the jumpers.

2. Two runs of bi-wire cables.

3. The 2.3 and 2.3TL are very different as are the 1.2 and 1.2TL. How much better is subjective. BTW, the 2.3TL does not have 2 more mid-drivers than the 2.3. It's just that on the 2.3's Polk used doughnuts on the top and bottom stereo drivers to slow them down. They are still active drivers.

My thoughts on your speakers. Don't worry about bi-wiring, just get the best single run cable you can afford and replace the stock jumpers with the same quality speaker cable. I highly recommend MIT Shotgun IC's and speaker cable, they even have matching jumpers. Power and source are VERY important also.

Lastly, if you call them "big girls" again, I will remove the speakers from your house and give them to someone who will respect them.

reeltrouble1

Big Girls have Big Bottoms and we all know THEY make the Rockin World go round!!!!!!!!!!!:cool:

RT1

fredv

Lastly, if you call them "big girls" again, I will remove the speakers from your house and give them to someone who will respect them.

OK, what about I call them my 2nd and 3rd wives with all due respect

-fredv-

F1nut

Originally posted by fredv
OK, what about I call them my 2nd and 3rd wives with all due respect

-fredv-

PolkFreak

fredv!

Quote from F1-nut:
1. You can bi-wire, you can use the jumpers with a single run and you can bi-wire and still use the jumpers. End quote.

The whole point of the jumpers is to connect the binding posts to use a single wire run on a single set of posts.


When you remove the jumpers you then have separate binding posts. The upper set is for the highs (tweeters). The lower set is for the mids and lows. You MUST remove the jumpers for BOTH bi-wiring and bi-amping. Bi-wiring is using two sets of cables, one set for the highs (top posts). Then another set of cables for the mids/lows (bottom posts). Both positive wires go on the single positive post on the amp end. Both negative wires go on the single negative post on the amp end.


Bi-amping you can look at the upper (highs) posts as separate set of speakers having the cables go to their own separate amp.
You connect the mids/lows to another separate amp of their own in the same manner that you did with the (highs) or top posts.

The amp that is running the highs should be setup to only send high frequency's. I know you can set AVRs to cut off the lows, but I never heard of cutting off the highs. That is what a crossover is for, but it is a good idea to make sure the amp for the highs is sending only highs. It is also a good idea to use the exact same model amp for both the highs and mids/lows.

So the whole point is that you must remove the jumpers for bi-wiring or bi-amping. If you just want to use a single set of cables keep the jumpers on and just use the bottom posts.

fredv

Hi Polkfreak,

Thanks for the explanation, but that leads to another question. In my case, my power amp only has one pair of speaker post. To bi-wire, I will run 2 sets of wires, one to the high and one to the low posts, but both will be from the same post on the amp side which effectively work like the jumpers. In theory, bi-wiring in my case is kind of like running a thicker speaker wire which is clearly a benfit, but other than that, is there any other benefit?

Thanks,

PolkFreak

Hi Fedv, if you look you will see that I explained that in my post above as well. If you have a good pair of ears on ya you should be able to tell the difference between bi-wiring and not. I've tried it with several different sets of wires. As well as listening to the same cd at the same volume. A volume that could be considered loud, but distorsion free without going overboard by pushing the limits. Look up some of my other posts that explain the use of different cables as well as using single wire runs VS bi-wiring.
If you can tell the difference between having your speaker grills on or off you should be able to tell the difference with bi-wiring.
That is with older speaker grills like the 80's Polks. They have better material that doesn't mute the sound so much with modern
day speakers. You won't be able to tell the difference as much with the volume at a low level. I'll explain again about bi-wiring the fact that you have 2 separate cables, but when you connect those cables at the amp end you are connecting both positive wires to the same single positive post on the amp. So the cables are separate until they get to the amp where you take the positive from the highs and the positive for the mids/lows and put them together as one wire on the single positive post of the amp.
Then take the two negetive wires (from the same speaker) and use them as one to connect to the single negetive wire post of the amp. The quality of the cable you use is going to make a difference in how much difference you hear when bi-wiring. Although I have used the Z series Monster cable with two separate Z series cables for bi-wiring I noticed a much better difference with their all-in-one Z2 bi-wire cable which was a surprise. I'm not advertising for Monster cable because you can get better for the money by going to http://www.signalcable.com/
Try their all-in-one bi-wire cable. Cheers! PolkFreak

Don't forget to put in a well recorded cd because some recordings are crap and lack depth and don't sound as 3d as others. Radiohead OK Computer is a good test cd. Radiohead is very depressing though, but its still cool sounding:D Pink Floyd Dark side of the Moon is a good test cd even though it is from 1973.
I have the SACD hybrid and it sounds great in 2 channel with my Polk SDAs.

PolkFreak

Opps, I see I forgot to answer your question and explained something I didn't need to all over again:D

To me bi-wiring separates the highs, mids, and lows with increased clarity and 3d quality. The speakers sound much more transparent. Some cheap speakers give the option to bi-wire or bi-amp, but they cut corners and just show you 4 binding posts on the outside and don't really separate the highs from the mids/lows on the crossover. I just bought some old Hitachi HS-350 speakers in good condition at the Goodwill for $4.26. They have a solid build with 8 inch woofers and horn tweeters. These seem like really high end 1970's speakers. They have a cool crossover with a switch that allows you to use a single set of terminals or a dual set with the ablity to bi-wire or bi-amp. I used them with both a single Z series cable run and the Z2 all-in-one bi-wire cables. The difference was awesome and I hear things on these that I can't on my SDAs. That will change once I upgrade the parts on the crossovers of my SDAs. There is just a small pinch of detail that my SDAs lack. Otherwise they are what I consider perfection. My friend who is an eletronics tech didn't see any advantage of bi-wiring from a technical standpoint listened to the Hitachi speakers with a single cable run and bi-wired. He was floored with the night and day difference. In some aspects it made more of a difference than bi-wiring my LSi 9's, but also made less of a difference in other areas. I bi-wired my LSi 9's with the same Z2 all-in-one bi-wire cables. When I used the bi-wire cables on those Hitachi speakers I could hear every bit of detail in the studio as if I was there, but the downside was that the speakers were super bright which to me is a harsh edgy cutting sound that doesn't permit listening for long periods of time.

F1nut

Originally posted by PolkFreak

The whole point of the jumpers is to connect the binding posts to use a single wire run on a single set of posts.

When you remove the jumpers you then have separate binding posts. The upper set is for the highs (tweeters). The lower set is for the mids and lows. You MUST remove the jumpers for BOTH bi-wiring and bi-amping. Bi-wiring is using two sets of cables, one set for the highs (top posts). Then another set of cables for the mids/lows (bottom posts). Both positive wires go on the single positive post on the amp end. Both negative wires go on the single negative post on the amp end.

So the whole point is that you must remove the jumpers for bi-wiring or bi-amping. If you just want to use a single set of cables keep the jumpers on and just use the bottom posts.

Not true!

There is no reason one can't use bi-wires and still keep the jumpers in place. While you are no longer actually bi-wiring the speakers at that point it does increase the wire gauge and can actually result in better sound than bi-wiring alone, but you have to use the same wire for the jumpers as the wire you're using for the speaker cable.

Another item of note is the method discribed here using two wires to the positive and two wires to the negative is not true bi-wiring, that's called a shotgun run. True bi-wiring requires two completely separate output posts on the amp.

My personal experience has been that bi-wiring alone is a waste and I get much better results using a shotgun run with the same type wire for the jumpers. Just ask anybody that's heard my set up.