View Full Version : Polk DB651 speakers - harsh "s" sounds and no bass at low volumes

12-05-2012, 12:28 AM

I recently changed out the 4 stock speakers in my Honda Civic for 4 Polk DB651 speakers. I really liked the way the speakers sounded in the display wall at a local Fry's store, but in the car I'm finding that they produce very harsh highs...especially with a female singer with "s" sounds. I'm also noticing that the speakers sound very tinny with virtually no bass until I start turning up the volume...which of course then starts causing an issue with the harsh high's and "s" sounds. I listen to these CD's through multiple headphones and at home through other systems and they sound great, so it is obviously an issue with my car setup. I installed the speakers myself and am wondering if anyone has any advice on what the issue might be?

I currently have the stock stereo system in the car as well, and plan on upgrading that to a Kenwood KDC-HD545U that I picked up.

Are the speakers simply not getting enough power from the stock radio?...should the new deck unit solve any of these issues?

When I installed the speakers, I cut off the stock Honda wiring clips, and twisted the stock wires with some thick gauge home speaker wire I had and capped them, then made hooks on the open end and hooked the wires in the respective positive and negative holes on the speakers. I figured that soldering the wires would probably be best, but didn't have a soldering iron at the moment. Is this a problem?...and will this create any of the issues like I am having?

Thanks to anyone who might have some advice.

12-05-2012, 12:44 AM
I had some polk tweeters that had some harsh sounds. I got a new set of xovers and wired them to -3dB and they were still harsh. turned my eq high end down and it was still harsh. replaced those 1" tweets with some massive audio 28mm tweets and the sound is golden. just my experience anyhow!

12-05-2012, 04:24 AM
if your new HU has EQ at 10/12.5Khz then try cutting back there to lose the "S" sound.

Are you running them off an amp? Takes some power to get decent midbass, also deadened doors will help. Might need HPF set around 80-100Hz on those mids, depending upon power level.

12-05-2012, 01:00 PM
Thank you for the advice. I will replace the head unit (hopefully this weekend) and see what kind of EQ settings it has to see if that will help. Also need to research deadening the doors as I'm not familiar with that process.

Currently I don't have anything besides the 4 speakers and a new head unit that I will be installing.

12-11-2012, 10:47 PM
I thought I would post a follow up for this thread in case anyone in the future might have the same issue. I upgraded the head unit to the Kenwood received I purchased and the problem is now almost entirely resolved. I can still hear a little sibilance if I turn the treble up really high, but it is night and day better than it was before. Thanks to everyone who shared ideas.

12-12-2012, 05:28 AM
Well, these are small coaxial speakers. Don't expect too much bass below frequencies below 100Hz. Most 6.5 woofers produce just enough bass to blend well with a subwoofer. It may also be a case that speakers are not getting enough power from the stereo. I would recommend to run a solid 50-70watts to a car-fi speaker, but the stereo decks normally provide 14-19watts RMS power. I'd say throw in a decent 5-channel amplifier, amp the speakers, and add a subwoofer.