Coaxial Dilemma

Peter

The front coaxials in my car died recently. They were OEM "extended range" coaxials-they merely had a filter capacitor for the tweeter.

I replaced them with a brand name coaxial at $130/pair. This pair didn't even have a high pass capacitor. I'm frustrated because the highs sound so shrill and glaring. And if this can be a contradiction, there's not much high end to speak of.

I originally wanted a coaxial with a crossover but didn't want the extra install hassles of an outboard crossover and mounting the tweeter, that's why I settled on the coaxes I bought.

So now I'm considering a pair of Polk db650s because of their built-in crossover, thinking that will improve the highs, and replace my rear speakers with the new coaxes for fill duties. Will the Polks be a cure for my problem? All I want are sweet, musical sounding high frequencies.

I should add that I'm using the factory head unit and it's a cassette, not a CD. I've played around with the tape bias, EQ, and noise reduction during recording to no avail.

Jstas

Forgive me please, I am not trying to be rude but I don't see where he complained of low-end response. He mostly mentioned high end response being less than desireable. However, speaker phase can cause high end response to be shrill and hollow.

As far as the new speakers fixing your problem, can't say. We have yet to identify your problem and rather than throw parts and money at it, lets figure it out first so we know what we are trying to solve. Kim asked a few good questions. If you can answer them, that would be alot of help.

As far as the speakers go, I have not known any speaker, ever, from Polk Audio to be shrill and glaring. They have a very smooth and fluid response. The response is also flat and detailed, unlike quite a few of thier competitors. I have had very little experience with the new DB line of speakers. However, judging by specs and what I have heard, the DB speakers will be what you are looking for. The factory power may be a little low for them but they will certainly have a smoother and much more full response than the factory paper speakers. As far as other aftermarket speakers, I haven't found much better for the price yet. There is better stuff but you'll pay twice as much if not more for it.

Your idea has merit. Moving the coaxials to the rear and filling the front with the DB's is a good plan to base something off of. It also leaves you a good base to start off with if you want to upgrade your electronics to aftermarket units in the future. I would like to know what the "brand-name" of you coaxials are what model if you know? It is not taboo to mention another company's name here and it is certainly nothing to be ashamed of at all, in any way. It would also help in understanding your problem better.

Jstas

I'm not disagreeing with you Kim, infact, in my post I mentioned that also. I was just saying that I didn't see where you picked up the low end response problem. He very well could have them wired out of phase. I've seen it very many times also. I just wasn't sure if you were addressing the correct problem. He mentioned high end performance and you mentioned low end performance. I was not sure if you were asking him to check polarity because bass response may have fallen off, making the highs too shrill or if you simply mis-read the post. That's all. Just trying to help.

Peter

Many thanks to both of you, Jstas and Kim, for answering.

The coaxials are Kicker K65s, a 6.5" coaxial. Jstas is right; bass is not a problem for two reasons-I have a powered subwoofer in the system, and I'm aware of polarity issues and verified the proper polarity of the speaker connections with the car's wiring diagram/color code. I'm an electronic technician by trade so I'm familiar with polarity issues.

The car is a '95 Saturn Station Wagon.

As for air gaps surrounding the speakers, I installed Dynamat on the doors right to the edge of the speaker openings, so the baskets seal tight. I also reused the Saturn speaker baffles, which are half open in the back anyway. Kicker's installation literature assures me the speakers are designed to operate in an open air environment, so sealing the back of the speaker off does not seem to be the problem here.

My problem is lack of highs and or what highs are there are shrill and grating. I've been so focused on this lately that I've been listening to other speakers, specifically home speakers, to see if they have the same quality. And no, they don't.

My home bookshelf speakers, a ten year old modestly priced pair, have a clean high end output. I even stopped into a deli the other day and noticed they had a pair of Bose 201s on the wall. I'm not a fan of Bose speakers, but I listened to them looking for their high end qualities. Even for an inexpensive pair of speakers they sounded fine. Remove the box and you probably have a pair of speakers that would be adaptable to a car environment, at a comparable price. Of course, I'm aware some changes have to be made for speakers to perform well in cars, and I haven't forgotten the crossover I'm sure is inside the Bose's, so why do I have a $130 pair of coaxials that sound horribly muffled in the lower highs and shrill higher up? Is it the lack of a crossover or are they just inherently bad?

I didn't buy the Kickers seeking low end response but admittedly, they don't seem to have a lot, yet I'm sure I wired them in phase. I continue to experiment with Dolby in/out, and bias and EQ, as well. I may see if I can easily reverse a set of speaker leads just to experiment, but I'm still of the opinion that they're just poor speakers and I'm under the "assumption" that a crossover would cure the problem. Besides, I also admit that Kicker doesn't strike me as being a speaker specialist, and having known Polk's reputation and longevity in the speaker world, I have great trust and respect in their products. And like I said before, I don't want the hassles of an outboard crossover and the Polks have that solved. Honestly, what's in a crossover at this level anyway, just one inductor and one capacitor, no?

I appreciate any and all advice you can give.

Jstas

Well first off, get all thoughts of BLOSE out of you mind!

There now, does that feel better?

Seriously though, the Blose speakers won't work for you. Most of thier home speakers have a high impedance and without the enclosures and crossovers and such, they don't work too well. So they are just a bad idea.


As far as the Kickers go, the K series isn't as nice as the series it replaces, the Impulse series. Overall though, Kicker is known for subs. The full-range speakers have never met much acclaim. However, looking at the specs, I am wondering what some other issues may be because they have a response of 40-20,000 Hz. They may fall short in the mid-range. They have a poly-graphite cone and it seems to be a heavy driver. That would make mid-range sound slightly muddled. The Kaladex tweeter is a screamer though and many people find them harsh.

I am wondering though, you are speaking of Dolby NR and other such issues associated with cassette tape play back. Are you experiencing this mid-range fall-off with just the tape player or is it the radio also? The reason I ask is even the very best cassette players on the market have a 15-18 kHz upper end limit. Also, Dolby NR, while very nice technology and effective, eliminate smostly tape hiss and background noise. It cancles out that hissing which usually falls right in the middle of the mid-range frequencies. Dolby NR recordings tend to be dull in the mid-range and peaky in the upper and lower limits. Could that be where your issue lies? Do you have a CD player hooked up to the stock radio? The reason I ask is because CD Players have a large frequency range than a tape player. You might notice that difference.

As far as upgrade go, the issue may not be your speakers. It may be the stock radio. Have you considered replacing it with an aftermarket unit?

What I think might help out if there appears to be nothing wrong is if you follow through on your idea. The DB675's have a frequency range of 35-22,000 Hz and they have a higher sensitivity rating of 92 dB vs the Kicker's 90 dB. That means that the Polks will play louder than the Kickers at the same power level. That is good. If you put the Polks in the front and move the Kickers to the back, it will help reduce the harshness of the highs because it will be farther away from you. That and all the different textures on the interior will help to diffuse reflected sound waves. That takes the bite out the tweeters. Since the Polks play louder, it brings your sound stage up front and lets the Kickers scream away out back. You will not hear the Kickers as well as the Polks because they will not be playing as loudly and the Polks will be on top of you compared to the Kickers.

MTXMAN

As far as the speakers go, I have not known any speaker, ever, from Polk Audio to be shrill and glaring.

IMHO the GXR's with their aluminum tweeter are a little on the harsh side... but i'm an avid hater of metal tweets to begin with ;p

Peter

I took Jstas' advice and compared my cassette's sound to that of the radio to see if it was a playback/Dolby problem. The muffled midrange and glaring highs remain.

I've ordered a pair of DB675s and will install them in the front doors, moving the Kickers to the liftgate. I'll report on the results here after they're installed.

Note for all: whenever installing speakers, keep your box and packaging materials until at least your store's return policy is up. I threw out mine, along with the unused speaker grills, almost immediately, thus could not return my unsatisfactory speakers.

Thanks to all your advice and look for my update.