6" woofer cheap at parts express

[318Joe]

While ordering my sub for Luke's box, I stumbled across these:

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=299-914

Now I know just enough about car audio to be killed in a freak stereo accident, but for $12 why not? They should fit in the stock location without modifications.

I'll post a review if anyone is interested. If you don't hear from me, it was the freak accident.

[318Joe]

Speakers came in today. First impression: they have an impressive heft, and look to be assembled well. Not that that means anything with regards to sound quality. If they sound as good as they are heavy, I'd be satisfied.

...but for $12 why not? .

Ok, well for starters, they are not car speakers, so while that has little impact on the speaker itself (all other things being equal), Mounting and channeling the proper frequencies to them must be addressed. In addition, the speaker lugs are of the narrow type, like what is used on the negative side of the factory speakers, so some cutting and splicing of your speaker leads, or soldering of larger lugs on the speaker is needed. All this is a long winded way to say they are not plug and play.

First the mounting: These have a reverse lip. Car speaker mounting flanges usually fold up, away from the magnet side, and come with some sort of gasket material (usually cardboard) for backside mounting. These fold toward the magnet, giving a raised steel edge aroung the perimeter on which the manufacturer has embossed "JAMO". Very suave, but unfortunately leaves us no flange with which to surface mount the speaker, nor does the speaker come with any gasket material for mounting front or back. The edge of the stamped steel basket is what would contact the steel of the front kick panel. Its not an insurmountable problem, but it is worth noting. Both of these shortcomings are visible on the photos at the Parts Express page if you look closely.

*correction* There is a flat flange with which to surface mount the speaker, the outside of the flange is just different.

Frequencies: Parts express published specs on their website, 80watts RMS, and 40-3500hz. So I will have to make a custom crossover. I was planing on using the factory tweeters for now. Factory used a 3.3uf cap, and it is an 8ohm driver, so I will start there, unless anybody has already invented this wheel and wants to chime in.

Here they are compared to factory premiums:

[Jean]

If you plan on using the same stock tweeter, use the same value cap for the high pass.

You can use this online calculator to figure out needed values:

http://www.carstereo.com/help/Articles.cfm?id=55

Stock crossover is 1st order (one cap for high pass in series; one inductor in series for low pass).

Typically a 6" speaker starts to "break up" or "beam" at 2500hz or more. So, with the 1st order that would be your starting point, or even less (2k-2.5k for example) since a 6db slope is very gradual vs. 12db, 18db, 25db etc. But the issue is the stock highpass crossover point for the 8ohm tweeter is at almost 6kHz, because it's 1st order. The higher order you go the lower crossover point you can pick (up to a point), because with shallow 6db (1st order) it can't keep the lower freq. away from the tweeter if the crossover point is low, so the stock one is pretty high.

So, to keep it simple you can even re-use the inductor from the stock speaker to see how it works...and then try other values if needed (partsexpress sells a bunch of different inductors / caps for crossovers). For audio use do not use polar electrolytic caps, use non-polar at the very least.

In regards to a speaker being car vs. home, the difference is in the material it's made out of, since car environment is harsher vs. home. Also, if you compare a home audio woofer and car audio woofer you'll see that on paper a car audio woofer does not have to go as low or have a lower FS (resonant frequency), because you have "cabin gain" working in your favor to boost the lower end. Vs. the home audio stuff that require a box of proper size etc.

[StereoInstaller1]

6 or 7 years ago, a guy I knew left some "white van" speakers at my house for me to fix.

I told him what it would cost, adn said "gimme money, I fix"

Never saw him again.

So, now I have these stupid "white van" speakers...the brand name? "AudioFile".

They have 2 8" woofers plus sealed back mids and tweets in crappy but nice looking particle board cabinets. There is also the 8" Jamo (Jamo are excellent, BTW. I have a set or three floating around, 5.1 micro crap) so I think I am gonna build me some kick ass garage speakers, or maybe fix them properly (new tweets, rebuild crossovers, brace and seal cabinets) and see if I can sell them on CL.

Any of you guys care to see a build thread?

Luke

[318Joe]

In the interest of not providing a single word answer, sure.

[318Joe]

If you plan on using the same stock tweeter, use the same value cap for the high pass.

You can use this online calculator to figure out needed values:

http://www.carstereo.com/help/Articles.cfm?id=55

Stock crossover is 1st order (one cap for high pass in series; one inductor in series for low pass).

Typically a 6" speaker starts to "break up" or "beam" at 2500hz or more. So, with the 1st order that would be your starting point, or even less (2k-2.5k for example) since a 6db slope is very gradual vs. 12db, 18db, 25db etc. But the issue is the stock highpass crossover point for the 8ohm tweeter is at almost 6kHz, because it's 1st order. The higher order you go the lower crossover point you can pick (up to a point), because with shallow 6db (1st order) it can't keep the lower freq. away from the tweeter if the crossover point is low, so the stock one is pretty high.

So, to keep it simple you can even re-use the inductor from the stock speaker to see how it works...and then try other values if needed (partsexpress sells a bunch of different inductors / caps for crossovers). For audio use do not use polar electrolytic caps, use non-polar at the very least.

Thanks for the help.

[318Joe]

Stock crossover is 1st order (one cap for high pass in series; one inductor in series for low pass).

Typically a 6" speaker starts to "break up" or "beam" at 2500hz or more. So, with the 1st order that would be your starting point, or even less (2k-2.5k for example) since a 6db slope is very gradual vs. 12db, 18db, 25db etc. But the issue is the stock highpass crossover point for the 8ohm tweeter is at almost 6kHz, because it's 1st order. The higher order you go the lower crossover point you can pick (up to a point), because with shallow 6db (1st order) it can't keep the lower freq. away from the tweeter if the crossover point is low, so the stock one is pretty high.

So for calculating the Jamo should I use the advertised rating of 6ohms or the re of 4.5?

6 ohms would give me about a .48 inductor rolling off at about 2k, 4.5ohms would be a .35.

Isn't that going to leave a hole from 2-6k?

[Jean]

Use the rating of 6ohm, because the 1st order filters are very "shallow" they don't both have to be at the same crossover point. So, even though you are crossing over at 3k or whatever it will still play 4khz and 5khz (crossover is not like an ON/OFF filter, you have to go higher and higher in order 24db and UP (usually done actively as the component count in such a high order passive crossover will make your crossover the size of your glovebox lol) and if you do crossover at the same point sometimes you get a "bump" at that point... just give it a shot and see how it sounds.

[StereoInstaller1]

Yup, a huge one.

One of the many reasons the vast majority of "car audio" speaker "systems" do absolutely nothing about the bandpass or simple low pass crossover.

IMO, the way to do it best is find a driver with a natural 6db/oct rolloff so you need very little crossover. That generally is rare and expensive (Dynaudio and Morel) or this new chinese driver over at Parts Express. Look at the response graph and you will see how a simple 6db crossover at 5Kish would clean that response up beautifully.

However, those are $140/pr and WILL NOT fit the hole of an E30, and I don't think they could be made to do so.

So on to something cheap and effective that WILL fit, and could even be made to angle: the Dayton Aluminum cone 4". About $15 each, decent power handling, easy/cheap crossover, but back to the same old hassles of home audio drivers in a car: no power handling, 8 ohms means you are wasting amp power, low Qts means very little mechanical cone control at low frequencies and it lacks "robustness"...but it is cheap!

I wish I could get 200 or so people together to do a serious group buy. I know I could spec something out that would WORK, and meet everyones needs, cheap.

[Jean]

Yep, a lot has to do with driver selection, but if you are working with what you have to will be playing with various crossovers.

Daytons aren't bad, but you don't want to cross those high either (at least a 4-5" mid can be safely crossover high vs a 6) :)

The usual paper cone drivers normally can be crossed higher vs the more exotic cone material mids w/o having to also implement notch filters etc...

[318Joe]

I wish I could get 200 or so people together to do a serious group buy. I know I could spec something out that would WORK, and meet everyones needs, cheap.

I'm in.

In the meantime, I'll crossover these and see how bad it sounds. Who knows, maybe it will be the same hole in the frequency response that made Mr. Bose so famous...

BTW the car will have the infamous Luke starter kit (box, crusher, premiums and 4ch amp) but the amp I have is a bit too much for the premiums, and I was thinking ahead...and trying to get to free shipping on the sub.

[318Joe]

Yep, a lot has to do with driver selection, but if you are working with what you have to will be playing with various crossovers.

Daytons aren't bad, but you don't want to cross those high either (at least a 4-5" mid can be safely crossover high vs a 6) :)

The usual paper cone drivers normally can be crossed higher vs the more exotic cone material mids w/o having to also implement notch filters etc...

I just want to know where I can find a high res version of your sig!

[318Joe]

Update:

Speakers installed up front. Replaced a set of cerwin vega 6" separates.

Much warmer sound. The cerwin vegas were not bad, but they seemed to be a bit harsh in the midrange using the cerwin vega crossovers paired with the factory tweeters.

Couple of points. First: heaven only knows what is inside that cerwin crossover (just a cap I'm sure) or what frequency it starts at. Second: Some of the "warmth" of that Jamo is probably due to that speaker dropping off at @3500. But, the bass was noticably stronger with some thumping happening in the kickpanels. These are going to sound nice if I can get the crossover and tweet sorted out.

As nice as the factory tweets are with the stock speakers, it is unlikely they will sound happy with these jamos, so while I'm having to make a custom crossover, I might as well use a better matched tweeter.

Soooo while shopping for the crossover components...

These roll off at about the frequency the Jamos are rated at:

http://www.parts-express.com/pe/pshowdetl.cfm?&Partnumber=279-061

These would fit in the factory pods without much modification:

http://www.parts-express.com/pe/pshowdetl.cfm?&DID=7&Partnumber=264-1018&ctab=1#Tabs

and moving a little higher up the scale, I think these can be modified to fit:

http://www.parts-express.com/pe/pshowdetl.cfm?&DID=7&Partnumber=275-040&ctab=2#Tabs

Don't know if that last set is worth the 300% higher price of the first set, and it is at the top of the budget range.

[Jean]

Mylar tweeters = garbage.

You can pick up a set of stock bmw tweeters from 93+ cars, they sound smoother/cleaner than the mylar crap.



The vifa one looks good as well, I would get that.

[318Joe]

Thanks, the vifas with the proper crossover components for the jamos puts the total at about $35. I will have to go easy on the volume, however as these are only rated @ 20wrms.

Quality, power , price. Pick any two, eh?