Polk Audio DXi650s - NO BASS

Are you running an amplifier??? If so I'd check your crossover settings.

If they are brand new - they might not be broken in and bass will improve over a few weeks.

Otherwise, amping them would help, sealing the doors would help, or maybe selecting more efficient speakers.

Hope This Helps!!!

Anyone else have suggestions?

I have an Alpine 50 watt amp I bought with the speakers, but I don't have it in yet.  That is the coming weekend project :-)

That should make a world of difference.

Let us know!!!

Most factory speakers do not sound great, mids and highs in particular. You probably notice a pretty major difference in those areas which can draw out some of your bass. The amp will certainly liven things up in all areas but your adjustability will be a ton better as well. Let us know how it goes!

Expect great dynamic range, but do not expect great bass below 100 hz.

just as an experiment, play around with the balance and fader.  it's possible that one or two speakers were wired out-of-phase.  it's a very common issue.  start playing some relatively bass-heavy music, and adjust the fader and balance so the sound only comes from a single speaker (the front left is what i will assume for this demonstration).  next, adjust the balance to the middle.  is the bass increasing more and more as you reach the center of the balance?  if not, you need to reverse the phase of the right (or left... doesn't matter) speaker.  that means reversing the POS and NEG wires on one of the speakers.  bass should ALWAYS increase as more speakers begin playing. 

okey doke, we've got the front speakers playing in phase.  now it's time to do the same thing for the rear speakers.  there are a couple of ways to do this, but the most time-saving way is to use the balance and fader.  start again playing some bass-heavy music with only the left front speaker playing.  now use the fader to play also the rear left speaker (nothing from the right side... don't touch the balance).  is the bass getting louder?  if yes, sweet!  if not, reverse the phase (switch the POS and NEG wiring) on the rear left speaker.  the bass should increase as you add speakers.

finally, we need to be sure the rear speakers are in-phase.  start again with the same bass-heavy music, with only the left-rear speaker playing.  adjust the balance to center.  does the bass increase or decrease?  if it decreases, you need to reverse the phase on the rear-right speaker.  if it increases, you're done!  all 4 speakers will be in-phase and you should have decent bass.

With the Polk Audio DXi650s have a 92db efficiency, so there aren't many options on the market to get more efficient than these speakers.  It does seem that an EQ setting is preventing these speakers from performing like they should. 

I see that you were planning on installing an Alpine amplifier, were you able to get that insalled and if so, did it help?

I'm with J Ro. I'm betting the speakers are out of phase. Do what he says.

K, I added the amp and the base response did improve.  I did not play with changing the phase.  I will try that before I add a subwoofer.  Thanks for the responses guys.

You WILL NOT get subwoofer bass response out of any full range speakers. Perhaps you are expecting too much out of those little speakers. The ability to handle high power does not equal low bass. You should, however expect the speakers to perform very well from 125 hz and up and MAYBE get decent response as low as 80 hz, but not loud bass like a subwoofer.

Yeah, I agree.  That is not what I was looking for in these speakers.  I was looking for frequency response AT LEAST as good as my factory speakers.  These did not deliver on that hope.  I lost some low end but gained quite a bit in highs, mids, and overall clarity.  To make up for the deficiency I may be looking to add a sub.

What head are you using for the source ? If it is the stock head, you are probably getting a preset EQ curve meant for the stock speakers. If you have installed an aftermarket head, you should have ran new speaker wire or RCA cables to the amp and to the speakers, bypassing any stock EQ/crossover/amp modules.

GLH

If it is the stock head, you are probably getting a preset EQ curve meant for the stock speakers.

this is very true, as stock HU's often have wild equalization embedded (and you cannot defeat it) meant to make only one set of speakers sound good... the stock ones.