Polk LSI-15s, minimal bass..

[ledust]

Let me start by saying that I am not an audio expert! I've owned my LSI-15s for years now, but have always been disappointed with the bass from these speakers. I currently have them connected directly to a Pioneer VSX-9040TXH (110W/channel @ 8 ohms) and previously had them directly connected to a separate NAD amp, C270 (120W/channel @ 8 ohms). Under both set-ups, bass production has been far less than I expected. I eventually do hear bass if I turn the volume up and stand at a certain spot in the room, but at that point, the bass that does come out seems disproportionate to the overall sound (i.e., voice/treble is a lot higher than bass).

I understand that people here recommend at least 200w/channel @ 8 ohms, but is that the main reason why I'm not getting the most out of my speakers? I typically don't listen to music loud, so that's why I never needed tons of power in my system. What I want is to be able to turn my music at a reasonable volume and still hear crisp, deep bass coming from the speakers. Will purchasing a more powerful amp solve this problem?

I've been looking at the Emotiva XPA-3 (200w x 3), but wanted to check w everyone here whether buying this amp would make a substantial difference to what I have now. Thank you!

[Jetmaker737]

I understand that people here recommend at least 200w/channel @ 8 ohms, but is that the main reason why I'm not getting the most out of my speakers?

Yes, your LSi's are being way under powered. You need a high current amp. I have not run the XPA amp but I did have the Emo RPA-2 (and before that I ran off my Onkyo TX-SR805). When I switched to my current amp, the Aragon 8008 mkII, I noticed a huge jump in bass response.

[nooshinjohn]

try flipping the speakers around so that the woofers face inwards, towards each other and properly towed in to face the sweet spot in your room. I run mine (when not using my SDA's) off of a Sunfire 600x2. They certainly do not lack for bass this way.

[treitz3]

Hello Ledust and welcome to Club Polk. Are you bi-amping the speakers off the AVR by chance? If not, are the binding straps at the speaker connections installed and tightened correctly?

Here's a copy of the owner's manual if you don't have one readily available.

http://www.polkaudio.com/downloads/m...9_15Manual.pdf

Now, looking at your AVR, you are seriously under powering these speakers which will cause a drastic reduction in overall performance to begin with. These are rated as a 4ohm speaker and your AVR is apparently built for an 8 ohm speaker which makes the two incompatible to begin with. We might be able to slightly improve your sound by answering the questions above but I think you are on the right track by looking for something that has a bit more juice to properly power those speakers.

When you do, you will have no issues with equaling out the lower octaves with the rest of the spectrum.

[Jetmaker737]

try flipping the speakers around so that the woofers face inwards...

Do you notice any loss of imaging with this setup? The manual states that for proper imaging the speakers need to be in their proper left/right positions.

[nooshinjohn]

Do you notice any loss of imaging with this setup? The manual states that for proper imaging the speakers need to be in their proper left/right positions.

In testing I have done, they sounded MUCH BETTER this way. The bass is more accurate and far less boomy than running them the way Polk recommends. We ran them both ways at the Indiana get-together and we all prefered them this way.

[Midnite Mick]

This surprises me as my thought on the lsi15 is that the tweeter was too laid back. If your response is changing that drastically pending on where you are in the room...it may be that the room is part of the problem. Have you tried playing around with different speaker placements?

Would it be possible to post some photos?

Regards,
Mike

[Midnite Mick]

In testing I have done, they sounded MUCH BETTER this way. The bass is more accurate and far less boomy than running them the way Polk recommends. We ran them both ways at the Indiana get-together and we all prefered them this way.

I imagine that would be dependant on room configuration.

[xcapri79]

Let me start by saying that I am not an audio expert! I've owned my LSI-15s for years now, but have always been disappointed with the bass from these speakers. I currently have them connected directly to a Pioneer VSX-9040TXH (110W/channel @ 8 ohms) and previously had them directly connected to a separate NAD amp, C270 (120W/channel @ 8 ohms). Under both set-ups, bass production has been far less than I expected. I eventually do hear bass if I turn the volume up and stand at a certain spot in the room, but at that point, the bass that does come out seems disproportionate to the overall sound (i.e., voice/treble is a lot higher than bass).

I understand that people here recommend at least 200w/channel @ 8 ohms, but is that the main reason why I'm not getting the most out of my speakers? I typically don't listen to music loud, so that's why I never needed tons of power in my system. What I want is to be able to turn my music at a reasonable volume and still hear crisp, deep bass coming from the speakers. Will purchasing a more powerful amp solve this problem?

I've been looking at the Emotiva XPA-3 (200w x 3), but wanted to check w everyone here whether buying this amp would make a substantial difference to what I have now. Thank you!

Welcome to Club Polk. I use a Emotiva XPA-3 with my LSi15's and get plenty of musical bass with them. Sounds like you are underpowering your LSi's. The bass response significantly improves using a good external amp.
Also, as treitz3 suggested, check the binding post connections at the rear of the speakers to ensure that your lower terminals are properly connected.

[ledust]

Thanks for the quick replies!! No, I am not bi-amping them. Each speaker has a single connection from the receiver, and the speaker themselves each have a gold binding plate that connects the posts together, which I've ensured is secured tight.

Also read about the 8 ohm/4 ohm issue the other day when i was searching the forums. I honestly don't know what an ohm is, but I understand now that there's a mismatch w my receiver and speakers. My receiver has the option to switch down to 6 ohm, but switching it didn't do much to the overall sound.

I never realized that the lack of power would affect the speakers considering that I don't listen to them at high volumes. So do these speakers have minimum power requirements?

[dkg999]

While you may be under powering your speakers, and don't have the best AVR to speaker match, maybe you should try some other things first. You noted that at one place in the room you hear better bass. Is there any option to move the speakers around a bit and see if that improves the bass. I would experiment with room placement before I started spending money on gear.

[xcapri79]

Thanks for the quick replies!! No, I am not bi-amping them. Each speaker has a single connection from the receiver, and the speaker themselves each have a gold binding plate that connects the posts together, which I've ensured is secured tight.

Also read about the 8 ohm/4 ohm issue the other day when i was searching the forums. I honestly don't know what an ohm is, but I understand now that there's a mismatch w my receiver and speakers. My receiver has the option to switch down to 6 ohm, but switching it didn't do much to the overall sound.

I never realized that the lack of power would affect the speakers considering that I don't listen to them at high volumes. So do these speakers have minimum power requirements?

Low impedance 4 ohms speakers require a lot more current from your amplifier than a typical 8 ohm speaker would. Most amplifiers inside a receiver are not built to adequately handle this additional current. Your receiver has a 6 ohm setting in it precisely to limit this current output to avoid damaging the receiver. To properly drive a low impedance speaker you need a suitable high current amp that is rated to at least 4 ohms.

The speakers also draw more current as the signal frequency drops. That is why bass puts even more of a strain on your amp. For this reason, it is suggested for HT to set the speakers to small and use an 80hz cutoff so that the low frequencies are diverted to the LFE output to feed a powered subwoofer. This significantly reduces the strain on your AVR amp. For a more full range speaker like the LSi15, this reduces the bass output that you might excpet to hear.

On my system with the LSi15's , I use an external amp and set the speakers to large so that I get the full bass signal to them. I also set the subwoofer to plus to ensure it gets the full bass signal. I adjust the SW gain to blend the bass to my liking.

[holt]

I have a VSX-9130tXH-k, which is roughly the equivalent to your receiver and I would never use it as the sole power source for my LSi15's as I'm the nervous type and I would probably imagine I was smelling burning or seeing smoke every time I turned it up... You're on the right track, get an amp, but also play with placement and other components in the loop. I have a 150w amp in 8ohm (250 in 4 ohm) and believe me, it sounds good. I love these speakers......

[ledust]

Yes, spent hours on end trying to move speakers around, settings, etc, but no luck. Even moved the speakers to entirely different rooms and still came to the same results. My expectations of how they should sound come from regular set-ups at Best Buy, and I know these speakers are capable of much more! I'm somewhat okay with spending money on gear, but wanted to make sure to check w the experts first. I previously thought that my separate NAD component system was to blame, but I found out that it wasn't the case after i replaced them w my new pioneer receiver.

[Jetmaker737]

For this reason, it is suggested for HT to set the speakers to small and use an 80hz cutoff so that the low frequencies are diverted to the LFE output to feed a powered subwoofer. This significantly reduces the strain on your AVR amp. For a more full range speaker like the LSi15, this reduces the bass output that you might expect to hear.

Perhaps the OP should look at his AVR setup. If the mains are set to "small" and he has no subwoofer there would be no bass signal below the cutoff going to the LSi's

[dkg999]

That was where I was going, check all the settings, room placement, etc. We're often too focused on buying an external amp or spending more money on gear when that may not be the best immediate thing to do.

[treitz3]

Pssst.....

http://www.polkaudio.com/forums/showthread.php?t=98866