Sub problem with LSi25

DVOuSS

I noticed today while watching transformers 2 that my bass seemed a little lacking. I got off my butt and went to the left LSi25...it was booming well as usual, went to the right LSi25, no sub. Now Im running the LSi25s powered subs off of my Onkyo TX-NR807 LFE channel (mainly because i do not have an external amp and figure polk's powered sub would be paired well with the amps they picked). Anyway i reach around the back of the speaker and verify that the "on" lamp is lit. Then i toggle it a few times from "on" to "off" then back to "auto". I then check my cables from the LFE channel. Still no sound. Finally I unplug it from the wall outlet, wait for the light to go out, then plug it back in, welcome back bass. Anyone ever heard of this or have an idea what it might be?

tonyb

Overload protection probably kicked in. The subs on the 25's are not meant for all that low end present in movies like Transformers. They are not a dedicated HT sub. Keep the volume a tad lower. Everything has it's limits, you may have just found yours.

DVOuSS

i see...while i love the 25s, the more time i spend here at club polk, the more the same phrase rings in my ear..."you need an external amp for the LSi series". This seems to be another one of those times. thanks tonyb

Mustang Matt

I have an LSi25, C, FX, 9 7.1 setup with a velodyne vrp-1200 sub.

Currently have 5 channels powered by an outlaw 750 and the two rear channels powered by an sc05 pioneer elite receiver.

All speakers are bi-wired. Except the LSi25s I can't decide if they should be biwired or not...

It almost seems like this speaker should have been setup for tri-wire. Two sets for the top and another input for the woofer.

In the manual, they never show a configuration using all four posts. They only use the top posts and then either LFE or preout.

What configuration would work best for me? I'm guessing my outlaw 750 would be a better source of power than the built in amps? Should I just unplug them and use all four posts?

Thanks guys!

megasat16

All possible connection to LSi25 is described in the LSi25 owner manual.

You can download LSi25 manual here.

http://www.polkaudio.com/downloads/manuals/home/LSi25Manual.pdf

LSi25 has built in subwoofer with subwoofer amplifier so you don't need to waste additional amplifier power to drive the sub in the LSi25.

If you want to bi-wire, the easiest way is to remove the jumper between two pairs of binding posts. Connect the amp to power the upper half of the LSi25 which compromises of tweeter and midrange drivers.

You can connect the RCA line out (preamp output) connection from your preamp or AVR or Pre/Pro to the RCA input of the sub amp to drive the sub.

Just remember to remove the gold metal jumper plate between the binding posts if you want to try bi-wire setup.

This is connection option 2 in the owner manual.

By the way, why do you think the LSi25 should have been setup for tri-wire? Do you think it'll help to feed more power to each driver (especially tweeter part)? It'll be a waste of an extra amplifier power for tri-wire setup for LSi25.

Mustang Matt

In the manual, they don't show any configuration using all four binding posts that I see.

In addition, my current configuration with one pair of wires going from the amp to the top set of posts and the bridge in place, makes me think the internal amp must be getting bypassed in any condition except for using the LFE/preout input.

So I have them plugged in for nothing right now I think.

As far as Tri-wire. It seems like two pairs could be used to power the top of a LSi25 like you would if it were an LSi9. Then a third pair or LFE could be used for the woofer.

Am I making this way overcomplicated?

megasat16

It seems you are thinking a bit much for the LSi25. The XO (crossover) in LSi25 is very different from that of LSi15 and LSi9 or LSi7 due to the active / powered sub incorporation in the design.

You can use both binding posts (in this case, no need to use RCA input to the sub) with bi-wire and bi-amp setup as in with LSi9. What happens is that if you use an amp to connect to the lower part of the LSi25 speakers binding post, the amplifier signal gets converted back to the line level by the sub plate, I think. So, it's a waste of power amplifier to power the lower half of the LSi25 which uses for the sub.

You need to turn on the speakers using AC mains using Auto On/Off or in On position to fully utilize the subwoofer in there. Or you simply don't get any signal to your sub and the sub won't work.

All connection diagrams are shown in the manual. They are labled Figure 5, 6, and 7.

[Deleted User]

Hello,
Keep in mind the LSi25 doesn't have bi-wire capability. It is a bi-amped speaker when you've connected your receiver or separate power amplifier to it. The two set of binding posts allow the owner to choose either a speaker level input or, removing the binding post jumper plates, a line level input to the internal bass amplifier. Bi-wiring would have meant three sets of binding posts not two.
Cheers, Ken

Mustang Matt

Interesting.

In figures 5,6, and 7 though none of them are using all four posts unless I am completely mis-reading. Based on what you've said where it would get converted back to line level anyway, it makes me wonder why they included them at all.

So in my configuration, based on my understanding of what you've said so far, it sounds like what I should do is run the amped pair to the top posts and split the preout signal that goes to the amp and also send it to the LFE on the speakers and use their internal amplifiers. The same way they have it setup in figure 6 in the manual.

Mustang Matt

Kenneth Swauger wrote: »

Hello,
Keep in mind the LSi25 doesn't have bi-wire capability. It is a bi-amped speaker when you've connected your receiver or separate power amplifier to it. The two set of binding posts allow the owner to choose either a speaker level input or, removing the binding post jumper plates, a line level input to the internal bass amplifier. Bi-wiring would have meant three sets of binding posts not two.
Cheers, Ken

Yah it's starting to make sense. The manual doesn't even mention bi-wiring like the other speaker manuals do.

I'm thinking this speaker deserved three sets of binding posts. In the end it probably doesn't matter though.

Does the LSi15 differ in that it's not powered so it's four posts work the same as the rest of the LSi series? If so, I kind of wish I had gone that direction as I suspect the dual NAD M25 amps I'm looking at would power that sub much better than the built in amplifier.

I should probably stop thinking about all of this and go enjoy it!

megasat16

Mustang Matt wrote: »

Interesting.

In figures 5,6, and 7 though none of them are using all four posts unless I am completely mis-reading. Based on what you've said where it would get converted back to line level anyway, it makes me wonder why they included them at all.

So in my configuration, based on my understanding of what you've said so far, it sounds like what I should do is run the amped pair to the top posts and split the preout signal that goes to the amp and also send it to the LFE on the speakers and use their internal amplifiers. The same way they have it setup in figure 6 in the manual.

Look at Fig 5, you see both pairs of binding posts being used in there with the single wire. There is no need to use RCA connection but the binding posts jumper are installed.

I know I called Bi-Wire setup for Fig 6 and 7 coz there involves one set of speaker cable and one set of RCA cable. This are 2 sets of wire involved in that config. Remove the binding posts jumper for both 6 and 7. These are bi-wire and single amp setup.

Yes, the internal plate amp seems to be used for the sub no matter how you connect it.

You can bi-amp using two speaker binding posts with two sets of wire but I think it'll be converted back to Line level by the sub plate. I think converting speaker level from line level is what it does in Figure 5 using the speaker jumpers between binding post so bi-amp setup is essentially waste of power.

I understand you are thinking tri wire as in one set for tweeter, one set for mids and one set for subs. You'll need three separate amps to do so.

Bi-Wiring with a Single amp is the same as using jumper between two binding posts and basically no sonic advantage to be gained (provided you use a good set of speaker cable in single cable setup).

Mustang Matt

megasat16 wrote: »

Look at Fig 5, you see both pairs of binding posts being used in there with the single wire. There is no need to use RCA connection but the binding posts jumper are installed.

Right, I was thinking no examples of both pairs of posts used without being bridged, but it's all making sense now that you guys have clarified it.

megasat16

Kenneth Swauger wrote: »

Hello,
Keep in mind the LSi25 doesn't have bi-wire capability. It is a bi-amped speaker when you've connected your receiver or separate power amplifier to it. The two set of binding posts allow the owner to choose either a speaker level input or, removing the binding post jumper plates, a line level input to the internal bass amplifier.
Cheers, Ken

Ken,

I may be wrong but LSi25 with binding post jumper in place is the same as what most people are normally and incorrectly using as bi-wire setup when the jumper plate is removed.

Bi-wiring would have meant three sets of binding posts not two.

I wonder what you mean.

Cheers,
James

Mustang Matt

megasat16 wrote: »

Ken,

I may be wrong but LSi25 with binding post jumper in place is the same as what most people are normally and incorrectly using as bi-wire setup when the jumper plate is removed.

It is in the same spot. What do you mean by "normally and incorrectly using as bi-wire setup when the jumper plate is removed"? I followed the directions in the other LSi manuals that said to simply remove the jumper and run two sets of wire. Is there another way it should be done?

megasat16

Mustang Matt wrote: »

It is in the same spot. What do you mean by "normally and incorrectly using as bi-wire setup when the jumper plate is removed"? I followed the directions in the other LSi manuals that said to simply remove the jumper and run two sets of wire. Is there another way it should be done?

Bi-Wire with one amp is the same as using single wire with one amp with the binding post jumper. Some said the jumpers makes sound quality inferior and they replace the jumper with good quality speaker wire instead. I guess that makes sense too.

That kind of Bi-Wire (two pairs of wire with one amp) is always incorrect to me no matter how many people say they used it.

No sonic advantage to be gained unless there is an external active XO involves there!

You are just making an extra connection in bi-wire single amp setup. If you use a good cable with one binding post, it is the same and as good as in bi-wire single amp setup (same scenario in Fig 5).

To me, Bi-Wire always should be with two amps (bi-amps) but some people just use with one amp mostly. That's why I called bi-wire is used incorrectly when used with one amp. With two amps and bi-wire setup, you'll at least gain additional db to the speaker even if there is no subjective sonic advantage.

Mustang Matt

But I was under the impression the speaker had an internal XO that came into the picture if you bi-wired it without the jumper. Is that incorrect?

I completely understand where you're coming from. If that's not the case.

megasat16

Mustang Matt wrote: »

But I was under the impression the speaker had an internal XO that came into the picture if you bi-wired it without the jumper. Is that incorrect?

I completely understand where you're coming from. If that's not the case.

Bi-Wire or not, the internal XO is in the speaker. You can't do anything to that internal XO with either one set of speaker wire or two set of speaker wire or one amp or two amps. It's fixed there. There is nothing can be done to that Internal XO with any kind of wire connection. You always use that internal XO with all kinds of wire connections (single wire or bi-wire or bi-amp).

How do you connect your LSi9? Two sets of speaker wires connected from the same binding post in your amp but two sets of speaker wires connected to two binding posts in your speaker?

It's essentially using the jumper in place.

Mustang Matt

Yes, I've got all the other speakers wired up the way you described using both sets of post and no jumper. In all honesty I did it with the anticipation of eventually bi-amping.

It makes sense that it's no different if there's nothing happening differently internal to the speaker.

I do wonder why the polk manuals mention it for the other speakers though.
http://www.polkaudio.com/downloads/manuals/home/LSi7_9_15Manual.pdf

They've got to have some justification for this statement don't they? Maybe it's only applicable if you were using too small of wire to begin with? I'm using 12 gauge everywhere which was probably large enough without bi-wiring.

"Bi-wiring [figure 8] can provide noticeable improvements in the overall
transparency of your loudspeakers. Run separate speaker wires to the low and
high frequency drivers from a single amplifier: after removing the jumpers,
connect one set of speaker wires to the upper terminals on each speaker and one
set of (usually heavier gauge) wires to the lower terminals. Connect the other
ends of both wire sets to the corresponding amplifier outputs. "

megasat16

Mustang Matt wrote: »

Yes, I've got all the other speakers wired up the way you described using both sets of post and no jumper. In all honesty I did it with the anticipation of eventually bi-amping.

It makes sense that it's no different if there's nothing happening differently internal to the speaker.

I do wonder why the polk manuals mention it for the other speakers though.
http://www.polkaudio.com/downloads/manuals/home/LSi7_9_15Manual.pdf

They've got to have some justification for this statement don't they? Maybe it's only applicable if you were using too small of wire to begin with? I'm using 12 gauge everywhere which was probably large enough without bi-wiring.

"Bi-wiring [figure 8] can provide noticeable improvements in the overall
transparency of your loudspeakers. Run separate speaker wires to the low and
high frequency drivers from a single amplifier: after removing the jumpers,
connect one set of speaker wires to the upper terminals on each speaker and one
set of (usually heavier gauge) wires to the lower terminals. Connect the other
ends of both wire sets to the corresponding amplifier outputs. "

If you read the manual again, you'll see your above question is quoted under Bi-Wire with Bi-amp setup. I don't know what Polk means but it's not clear to me too. But I think that statement does not apply for Bi-Wire with Single Amp setup. If you got bi-wire ready, you just need to get additional amp like you said. Bi-Wire with Bi-amp setup is quite an improvement for LSi7, 9 and 15 but not 25 unfortunately.

In fact, I suspect adding bi-wire for such connection will only result in additional increase in wire's resistance and capacitance thus making the sound worsening than with a good single wire setup.

Anyway, we got Polk to clarify what they means.

And yes, 12AWG is good wire size for most speakers. I used 10 with mine though.

Mustang Matt

There's actually a separate Bi-amp statement. The one above says:
"Run separate speaker wires to the low and high frequency drivers from a single amplifier"

That's where I'm getting confused. It sure seems to be stating exactly how I've got mine currently wired.

megasat16

Well, you know, sometimes people says things a bit confusing but you got the question to ask and I know some folks here will chime in soon.

And re-read my previous post as I made a little revision to it. Yes, I see what you mean in the manual.

kawizx9r

What Ken described earlier sounds just like my Polk RT1000P's I used to own.

There are 2 sets of binding posts;

First set - For the tweeter+midrange drivers.

Second set - Is a method of sending a signal-only to the built in sub amplifier in the tower.

Since the LSi25's only have two binding posts, my guess is that the second binding post is for just that; sending a signal from amp/receiver to the internal sub amplifier in the tower.

It's there in case you either;

1. Lack a dedicated subwoofer output on your receiver/preamp.

2. Are using the LFE output on your receiver for a separate subwoofer and don't want to daisy chain or use y-splitters between subwoofer+tower speakers.

The second set of binding posts are not for bi-amping/bi-wiring the LSi25.

-Freddy

[Deleted User]

Hello,
The two sets of binding posts, on the LSi25, are there to allow the owner to choose either to give a speaker level signal to the internal bass amplifier. Or, to remove the binding post jumper plates and use a non-amplified line level signal to the bass amplifier. Let's say I want to connect a Fisher 500C to a nice pair of LSi25s. The Fisher doesn't have a sub-out connection, the only outputs are a tape out for recording (which won't work well) and the normal speaker level outputs. No problem, leave the binding post jumper plates, on the rear of the speakers, in position and make my normal right and left speaker wires to either the upper or lower set of binding posts. I now have a bi-amped set of great sounding speakers.
Let's say I upgrade a few years later to an Audio Research SP6 and matching D75 power amp. Now I have a line level pre-amp signal I can send to the speaker's bass amplifier. I remove the binding post jumper plates and leave my speaker wire attached to the upper set of binding posts. Then I run a right and left RCA cable to the corresponding right and left line level input from my SP6. Another set of line level connections will connect the pre-amp to the power amp. The D75 is connected to the upper set of speaker wires for both right and left channels.
The four sets of binding posts enabled me to go from a speaker level to a line level feed to the bass amp.
Cheers, Ken

megasat16

Yep Freddy, Crystal Clear Now!

One can use bi-amp bi-wire but nothing to be gained there. All the power in the lower sub section got converted back to line signal always. It's a waste of wire and an extra amp power. I did try RCA with mine in all possible connections but it doesn't do anything better.

So, one good wire with one good amp makes LSi25 sings admirably.

kawizx9r

One thing though, make sure you do NOT have both the jumpers in place and the internal amplifier hooked up to a receiver/processor via LFE.

Only use one method of connecting the internal amp.

-Freddy

Blackswan

I have my jumpers on and im conected on the bottom posts and have subwoofer hooked up lfe i am as wrong as two left feet is that why im, not getting bass out of subwoofer

mlistens03

I know this is an old thread, but I believe that with the other speakers in the LSi line the top posts are for the tweeter and the lower posts are for the woofer, right? And then you could use an active XO and send signals directly to each driver, bypassing the internal crossover entirely. (I think the signal still would run through the XO but it wouldn’t need to do anything, so it would basically just be a wire inside of the cabinets).
I feel the same way with the 3 sets of terminals thing. I wish they literally just put a LSi 9 on top of the he subs, with the same terminals and everything. Then the top section would work just like an LSi9. They could have put all 3 sets of posts near the bottom, and used the subs high pass inputs with the same bridge plate to the woofer and the top section midbass drivers.
If there wasn’t a high pass XO in the LSi25 towers top section (you know, the one that cuts everything below 90 hertz), I wonder if you could plug one of the front ports and then have it play deeper... just thinking.

Micah

[Deleted User]

"the other speakers in the LSi line the top posts are for the tweeter and the lower posts are for the woofer, right? "
Actually the binding posts connect to the filters on the crossover, which in turn are connected to tweeters and drivers. The internal crossovers would have to be removed in order to bypass them and use an external crossover. Not for the faint of heart.

mlistens03

Yes, but what I meant is using the two posts with an active XO and two amplifiers (or in some cases, 2 different channels on your avr) you can send signal directly to the tweeter and signal directly to the woofer. It would still pass through the crossover, but the crossover wouldn’t have to do anything, which in theory would basically be a high pass filter for the tweeter or a low pass filter for the woofer. I don’t know if this is correct, but this is how it works on my 90s infinity tower speakers, and I just assumed that was what the basic idea of the design was. Probably shouldn’t assume next time.

[Deleted User]

"It would still pass through the crossover, but the crossover wouldn’t have to do anything, which in theory would basically be a high pass filter for the tweeter or a low pass filter for the woofer."
Do you mean that the external crossover would be set to a cutoff frequency that would be higher than the internal high pass filter? Let's, for discussion's sake say the high pass filter built into the speaker is at 2,000Hz, so you're proposing to send a signal to the speaker that is say, 4,000Hz so it doesn't interfere with what the builtin high pass filter is doing?

mlistens03

Yes? I think. The idea behind the design in my infinity speakers was that you could send the highs to the top posts, and the lows to the bottom posts, and set the active crossover to whatever the internal crossovers filter was set at, then the signal wouldn’t have to be filtered at a speaker level. This would mean that the internal crossover wouldn’t actually be doing anything, as there wouldn’t be any need for filter because the low frequencies are already being sent to the woofer, the mid frequencies are already being sent to the midrange, etc. that is how I think this works anyway.
The infinity speakers in question are Crescendo CS-3007s, so you can google them if you like, I will later but I don’t have time right now.
Micah