tharaka

iTrader: (1)

Hi guys, about a month back I asked how to tell if my stock speaker system had an inline capacitor to its tweeter (as one of the tech manuals I read for the car stated it did) and got a lot of help in that area - but without taking apart the door panels I was left inconclusive.

Using the stock wiring to the factory speakers, I installed a new HU and amps to power all speakers recently. I also replaced the tweeters but kept all the wiring. The front is a three way setup from the factory (Low, Mid, High). For the Mids and High I used a crossover from a JBL set of components I had lying around, as the tweeter matched the specs of the original JBL this was for and the mid range was close in impeadence to the JBL woofer. Now the problem is barely any highs come out of the tweeters!

I've been reading up on passive crossovers, and I'm guessing that the speaker is 'seeing' two capacitors in series, one from the factory wiring and one from the JBL crossover. Capacitors in series result in a load that is almost halved - which has the result of raising the HPF on those speakers - this is just a guess for now and hence why very little sound is being output from the tweeters.

Now my question is can I bypass the crossover (I know, using this wasn't a good idea to begin with), and wire the L/R mid/high in parallel, directly to the amp, an inductor to set a LPF of about 7-10k Hz with the mids, thus thereby retaining the factory capacitors?

Cheers,

92zed34

iTrader: (4)

I would try it but first it might be an idea to check the resistance(ohms) of the speaker line with all those in paralell, meaning check at speaker leads were you are hooking to amp.
youre amp is stable prolly down to 2 ohms so anything above that would be ok(amp wise)anything above 4 ohms youre not gonna get decent power out of youre amp.
But what i would do if i were you is try to use the component crossover,take the time and take youre door apart and replace the factory peice with the jbl.

tharaka

iTrader: (1)

woops - I meant parallel in my original post - doubling up on the + and -

I know the factory mid is 5ohm, and the tweeter about 3.75 = so thats about 4.5ohms in parallel.

I do have t take the door apart at some time to install some dynamat but the weather in Toronto has been rainy the past 2 days and don't have a garage to work under. I was thinking of just running new wiring to the tweeters when I remove the door panels as well.

92zed34

iTrader: (4)

I figured you meant parallel but 5ohm+3.75 equals out to be just over 2 ohms about 2.14 actually.
rule of thumb is when you put two ohms values together you wind up with half.ie, 4+4 =2,8+8=4,2+2=1, etc
Opposite in series.
I would check the impendence of the factory speakers/tweeters you are using,lets say if the mid is two ohms an the tweet is 8 ohms i would think the mid would be demanding more power than the mid,resulting with issues youre experiencing.
What brand/kind of car are you working with?

tharaka

iTrader: (1)

My bad, you're right, its 2.14 ohms in parallel. I'm retaining the factory mid for now, using a multimeter it reports as 5 ohms. I've replaced the stock tweeter with an Infinity 1021t 4ohm tweeter, which reads about 4 ohm at the multimeter.

So the difference is about 1 ohm off, which isn't that bad between the mid and tweeter. They should be equally demanding somewhat.. even stranger is the fact that the tweeter has a high sensitivity rating (93 db 1w@1m) so it should be screaming when I turn it up.

Its a BMW z4 Convertible that I'm working on and it has the upgraded speakers (keeping most for now until budget allows for a speaker upgrade).

One side question - could my lack of highs be a result of having reversed + and - connections, or would that just cause a phase issue?

92zed34

iTrader: (4)

Could very well be a phase issue,most projects and cars ive done installs on are not very factory/afermarket friendly,due to simply the consumer buying high rms values and factory speakers are low wattage rms values...
Most factory speakers are really low wattage 10-40 watts but are efficient in there frequency range.
Best advice to you bro is replace all or nothing.....

tharaka

iTrader: (1)

Ok I think I get what you're saying.. at low RMS - the factory speakers will sound good b/c that's how they were designed (efficient) but that same RMS level won't be enough to power my higher powered tweeter.

I have looked at a pair of CDT HD3 Mids that I might use as a stock replacement, but they are only 30W RMS - would I run into the same issues here again if I went with the CDTs?

My last option is to amp the tweeters separately from the mids.. after that I'm outta ideas.

92zed34

iTrader: (4)

buy a component set midbass/tweets with the proper crossover and you cant go wrong,amp accordingly.
The problem youre having says to me the set is way off(miss matched)

tharaka

iTrader: (1)

ok, just finished wiring it in parallel, sounds a hell of a lot better for now.. the tweets are producing what seems to be the right frequency at lower volumes.. the hu I have can let me adjust the mid center frequency and the band.. so I can tune them in how I like - all is not lost.

Next project will be a proper replacement of certain speakers.. thanks for the tips guys.