advise on cutting bass to 3way 6x9's

[dr.Quirky]

hi, im new here. read up a good few threads seems a great place to ask!

i seen an article HERE suggesting using capacitors in parrellel on line goin to back speakers as a kind of crossover to stop them distorting at high volumes, would people here advise this?

Im running an amp powering a sub and two 6x9's on back shelf, its a grand set up but the 6x9's get a bit distorted past half way, could this be a solution? im not very electrically/audio savvy but know the basics, i dont hav a manual for the amp so i dont know what frequencys are cutting off or what the low end capabilities of the 6x9's are.

Please advise

[Cal Weldon]

Certainly you can. It will be a big cap so not cheap unless you opt for an electrolytic. This might not be that bad for a car audio set up. What is the ohm rating of the 6X9 speaker and what is the upper frequency of the subwoofer?

EDIT: Just looked at the link and they seem to be using a polarized cap. I wonder about this as it's an AC circuit. Probably best to use a non-polarized cap.

[chris661]

It might be an idea to add an inductor - 6dB/octave won't reduce excursion by much, unless you brought it in at more like 150, 200Hz.

Making it 12dB/octave would mean excursion is reduced a lot more.

[sqnut]

why not just disconnect the 6x9's and just add front comps?

[dr.Quirky]

Originally Posted by sqnut

why not just disconnect the 6x9's and just add front comps?

front comps? lik run the 6x9's off the HU ?

Originally Posted by chris661

It might be an idea to add an inductor - 6dB/octave won't reduce excursion by much, unless you brought it in at more like 150, 200Hz.

Making it 12dB/octave would mean excursion is reduced a lot more.

im sorry, excursion? im lost, would i add the inducer on line with the 6x9's?

what is the ideal cut off for 6x9's/sub would 150 or 200hz leave too much of a sound gap from the low end of the sub? im not too pushed on SQ once its free from distortion at higher levels.

[chris661]

Excursion - cone travel. When the speaker passes it's linear excursion rating, you get distortion. Cutting the bass allows the cone to do better on the lower midrange.

This will help you calculate what values to put in.

Passive Crossovers, Capacitor and Coil Calculator

I'd say you could cut it as low as 70-80Hz, but if you wanted pure SPLs, you'll want it higher. (150Hz ish)

Chris

[col]

Most car 6x9s are 4 ohm. If you have a sub you can probably use a high pass filter at around 200Hz. Use a
200uF 100V Non-Polarised Electrolytic Capacitor in series on the positive lead going to the speaker.

200uF 100V Non-Polarised Electrolytic Capacitor - Jaycar Electronics

col.

[tsmith1315]

Originally Posted by dr.Quirky

front comps?

sqnut was suggesting that you do away with the 6x9's altogether and put a nice pair of component speakers (separate midrange & tweeter) up front. A great option for sound quality, but not in the same price bracket as a pair of capacitors.

Originally Posted by dr.Quirky

what is the ideal cut off for 6x9's/sub would 150 or 200hz leave too much of a sound gap from the low end of the sub? im not too pushed on SQ once its free from distortion at higher levels.

To answer that, look back at Cal Weldon's post:

what is the upper frequency of the subwoofer?

He asked that question to answer your cut off question before it was asked. You must know what the rest of the system is doing in order to integrate as best you can. Had you said the woofers cut off at 80Hz, he would have probably offered a capacitor value that would roll the 6x9's off around 80-100Hz.

A pair of capacitors will provide an estimated cutoff. The actual response will depend on the 6x9's reactance, and that varies from model to model regardless of their rated impedance.

With all that said, for $5 or $10 you can't beat a pair of 200uF or 300uF (NON-Polarized!) caps as a quick fix to help things out. If you want to spend more, you can do even better.

[mavric]

Why not use the HPF on the amp? Most have a cut off at 250hz..
What kind of amp? 2 ch 4 ch?
you might need to nothing other than setting your amp up for 2 ch sub/ 2 ch mids high.
What kind of car? Thats why the componts where mentioned, you wand your mids/highs up front, not behind you.

[dr.Quirky]

thanks all for advice , the 6x9s are pionneer 4way coaxial 380w max i dont know what thats rms , it says 80w nominal . the amp has no hbf, its only 2 channel, i have no manual or anything from the amp i ont know what kind of hz range its putting out.

Its a nissan micra im looking into getting front comps once funds become available. thought the caps might be a cheapo solution.

I think im going to go with a pair of 200mf non polarised caps and see how that works. might get a pair of 400~350 ones and try them aswel

Thanks for all advice