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Frequency crossovers

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Old 04-03-2011, 02:21 PM
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Unkle
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Default Frequency crossovers

Hi

I have a 5.25 component set of Rainbow speakers and want to upgrade the crossover (it has the P original) with something small and relatively cheap that will fit in the space in the door pocket.

The mids and tweeters should be good with the Becker headunit i have, but i can't get a natural sound and believe its partly due to the original crossover which isn't really compatible with after market speakers, but in case its not the problem i don't want to spend loads finding out.

Any ideas would be appreciated...
Old 04-03-2011, 10:19 PM
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springer3
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I posted the cross-over frequencies several years ago when I changed the crossovers. I recall that the factory system was way different, and can confirm that it would not sound good with after-market speakers.

Good luck
Old 04-04-2011, 12:17 AM
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windblown
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I would not use the factory crossovers for aftermarket speakers! When I purchased my car the previous owner installed polk audio component speakers with the factory crossover and he could never figure out why it sounded so bad; I replaced the factory crossovers in the door with the correct crossovers from polk and they sound amazing. Pretty easy to switch out, I did take the plactic pocket that the factory crossovers fit in off the door panel and the now the new crossovers share a bit of space in the arm rest area; not noticable at all.
Old 04-04-2011, 09:06 AM
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Unkle
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thanks, at least it confirms my thoughts about the crossover being the problem. Do i need to get the ones for my speakers? Or will any 2 way crossover from a reputable component set work?
Old 04-04-2011, 10:17 AM
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I used to run Raibow Profi Kick Bass and really liked them.

I have a set of crossovers from some MB Quart speakers you can have, PM me your address and I will ship them out to you.
Old 04-04-2011, 02:29 PM
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Unkle
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Thanks Daryl - pm sent
Old 04-04-2011, 05:12 PM
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Rally Guy
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Careful there!

Xovers are typically designed SPECIFICALLY for the drivers and applications they are mated with. Just swapping Xovers in and out is a risky proposition and the odds of hitting on the right slopes, frequencies and other design parameters for your application are very very low.

Also - "small and cheap" will get you crappy internals (like 15-cent caps) and you won't be doing yourself any SQ favours.

How is it you have a component set that DIDN'T come with an xover? I'd go back to that manufacturer and get the RIGHT xover for that system. Else - if you really DO want a "natural" sound, then you'll be FAR better off sourcing a new set of components by a reputable firm - like Focal or MBQ.

Sorry - the audiophile in me is just trying to look out for your ears! ; )

RK
Old 04-04-2011, 05:42 PM
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Unkle
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Hi

Thanks for your advice on the compatibility of the crossovers

Rainbow are very reputable in Europe, don't know if they are popular in the US/Canada, but the speakers were fitted in the car when i got it thankfully as a set of Rainbow component speakers can get expensive.

Rainbow Speakers

If it was the ones above i would have sold them for further mods by now, but mine are a little further down the range



On closer inspection, to try and identify why the sound was a little off, I noticed that it has Porsche crossovers and the person that fitted them didn't fit the Rainbow ones, or had them fitted and the fitter cut corners.

I have contacted a Rainbow distributor in the UK and am waiting for a response. I'm not really an audio person, but even to my very untrained ear it sounds a little off. I took the amp out and the rear speakers so i have just the Becker headunit and these components. Without a amp etc i won't get great sound, but a £20 pair of speakers would sound better at the moment.
Old 04-04-2011, 05:48 PM
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Rally Guy
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I don't know them - but will check them out for sure.

If they are good speakers - then it's totally worth sorting them out for sure! Great plan to contact the source!

But also - tuning of the system - ensuring phase alignment, set up of the HU (head unit) etc can make a HUGE difference.

Even the total audio keeners lament the effort it takes to tune a system. I spend hours yesterday tweaking the time delays in my active HU in mere millisecond increments to get a great sound (let alone the other hours fiddling with a super powerful 5-band parametric eq set up!) and STILL I don't have it right! Ugh.

So, take some time - get it sorted and you should be thrilled with the results.

Frankly though - the HU won't have enough juice to run those speakers well - so an outboard amp is HIGHLY recommended.

But if you choose NOT to run an amp - the VERY LEAST you MUST do is power the deck with a DEDICATED power lead directly from the battery.

The stock wiring harness CANNOT deliver enough current to allow that deck to "breath" like it should.

Let us know how it goes!

RK

PS. Holy Crap! Just checked out the site... those are potentially some amazing speakers! I'm impressed and now implore you to power them properly! Let's get those drives singing!
Old 04-04-2011, 05:55 PM
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Unkle
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Thats interesting about the power lead. i will look into it, should i also make the earth lead big as well?

Dumb question #1 Do you connect it to the thin power lead on the back of the headunit in the same way? doesn't that still mean it goes into a small wire before the unit? or does that then no longer matter as the large gauge wire is running most of the way?

I took the rear speakers and amp out (last year) to get rid of any weight and power drains on the battery, and the engine noise is too nice to drown out all the time. I would have binned the front speakers but for noticing the brand, then i wondered why they sounded bad. I checked the phase for the speakers as the first thought then found the crossovers and thought thats why they sounded so poor.
Old 04-04-2011, 06:01 PM
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Rally Guy
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I think you've got the makings of a strong system...

Put the amp back in (brand, model?) and wire it to drive the fronts now. No need for the rears in a 911.

Then sort out the phase and xover issue and you're going to be one happy camper, methinks.

The weight of the amp is trivial - it's like the difference between having stopped for milk on the way home or not - its a non-issue for the return in sound quality. (And of course the power lead advice goes DOUBLE for an amp.

Earth lead isn't as key - most of the energy has been lost to driving the speaker and heat - so a SOLID earth is key - but it needn't be as massive. Just keep it short and to directly to the frame (having burnished the paint away first for the connection).

RK
Old 04-04-2011, 06:29 PM
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Unkle
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Can't remember the amp brand it was old and still had power but no audio leads to it so i launched it.

Sorry one more question, If i run the power lead to the battery should it be fused and what gauge cable? i have some 8awg but i assume thats too big ?
Old 04-04-2011, 06:49 PM
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Old? My Vandersteen home speakers are from 1990-something - they sound WONDERFUL!

There IS a school of thought that says - to a point - older car audio stuff is better. Especially for amps - did you "bin" it already?? ; (

Anyway - 8awg is overkill - 12 is prolly fine for the deck. Yes fused for sure! Try 20A first - that should be fine.

But you can decide for youself with this...

http://sites.google.com/site/interfa...ilable-current

RK
Old 04-06-2011, 10:51 AM
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Hi guys. Thanks for posting this thread. I replaced all of my torn speakers with after-market Sony and Clarion speakers when I got the car. They are fairly basic and mostly chosen just to fit the existing aperture. The sound from the front Sony speakers which are rated 150W/35W rms is pretty poor (one is worse than the other for some reason). I was just starting to pull them out and investigate. I'd probably wrongly assumed it was something to do with the head unit until I saw your thread. It's probably a dumb question for you guys who know more about audio than me, but could the X-over be bypassed if the new front speakers covered a frequency range that included the old tweeters - not sure if they would but the spec says Frequency response is 60-23,000Hz with Sensitivity 86dB/W/m?
Thanks again for the post.
Regards
Dave
Old 04-06-2011, 11:32 AM
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Unkle
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Yes, it can be bypassed. Its a passive crossover i understand, so you can simply remove it and then wire in the speakers normally. However only do this if you have full range speakers i.e. a speaker with a tweeter built on the front. i think they are called coaxial speakers too.

If you have component speakers (separate tweeter and woofer) you really need crossovers to split the sound to the specific speakers. Tweeters won't last long if full range sound is pushed through them, and it will sound bad too. Recheck all the connections and make sure the + and the - are the same way around on all speakers or they will be out of phase.

This is my uneducated 2 pence


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