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De-Bose-ifying my Miata / MX-5
De-Bose-ifying my Miata / MX-5
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Old 2nd April 2007, 07:31 PM   #1
maharashii is offline maharashii  United States
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Join Date: Apr 2007
Question De-Bose-ifying my Miata / MX-5

Hello crew,

Current Setup
I have a 1999 Mazda Miata (aka MX-5) that originally came with a Bose HU, amp, and .5 OHM component speakers.

I removed the HU and replaced it with a Nakamichi CD-400. I have an Omnifi DMP-1 in the DIN slot formerly occupied by the cassette player.

I have bypassed the Bose amp entirely, and ran new wires into the doors.

In the 8" round speaker openings, I made an adapter out of MDF and mounted a spare set of 6.5" infinity reference series components.

The next evolution in my stereo
Next up I want to add an amplifier to power the door speakers, and possibly replace the speakers themselves, since I believe I can do much better than the infinities. My goal is to attain the best SQ I can get with enough SPL to overcome the road/wind noise I might get with the top down on the highway.

I am open to component sets, coaxials, 6.5" or 8" woofers, passive or active crossovers, etc. The only constraints are that I have a budget of $600 for the amp / speakers / crossovers, and the amp should fit behind my passenger seat or in the tunnel connecting the trunk to the passenger compartment (max 6.5" width).

What products can you guys recommend for that budget?

Future plans
My future plans include a pair of small subs, probably mounted in the shelf behind the seats, possibly a set of small coaxials to handle midrange installed in the kick panels, and if I can manage it, fully active crossovers on all channels.

Obviously I'd like to minimize acquireing anything that would have to be replaced to meet my future goals. I do, however, have to work within my budget.
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Old 2nd April 2007, 11:01 PM   #2
maharashii is offline maharashii  United States
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Join Date: Apr 2007
DLS was recommended to me on another forum, but their Iridium series at least was way out of my price range.

I was also told to look at the Soundstream Tarantula amps. Unfortunately those things seem to be massive. At ~20" long they would occupy a huge amount of trunk space and I'm not clear that one would fit behind my passenger seat either.

I need to maintain as much seat travel as possible.
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Old 3rd April 2007, 12:02 AM   #3
MadMutt is offline MadMutt  Australia
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Join Date: Nov 2006
Was an article in 'car audio and elec' maaaaaany years ago where they redid an mx5.

Sub they used was an 8 or 10 (can't remember) but the box they made was a dog leg that fitted into that space you have between the boot and cabin.

They put the port in the end that fed into the cabin, they then drilled holes into the top of the metal of the car under the trim in the cabin.

Probably not a very good description sorry.

Think of an 'L' shaped box with the port in the cabin and the speaker in the boot.

Ended up not using any boot space at all.

In regards to cutting into the rear wall of the cabin;
I don't think you can, doesn't the soft top fold into that space ?

If you can fit a decent 6.5 or bigger in the doors then a sub might not be needed as badly.
ADS have some really good bass from their 6.5's.

Celestra amps are quite small, might fit a four channel (bridge one pair for sub) under the seat.

Been a while since I've worked on an mx5, might be room behind the glove box/dash for an amp.

Being a mazda it will need to have sound deadner applied, they really are terrible for road noise.
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Old 3rd April 2007, 05:51 PM   #4
maharashii is offline maharashii  United States
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Join Date: Apr 2007
I have fat mat in my doors already, and I have some more that I plan on applying to the floor and transmission tunnel.

I'm curious about the Celestra amps. Do they provide good SQ? I'm not having luck finding a retailer. Can you recommend any?

How about the speakers? I think I could do better than my current set of Infinities.

I'd like to hear more about your sub box idea sometime, but I'll save that for another thread. First I went to get the front soundstage worked out.
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Old 3rd April 2007, 05:51 PM   #5
maharashii is offline maharashii  United States
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Join Date: Apr 2007
The Celestra VA (reference series) doesn't offer a 4 channel amp, only stereo. That concerns me on price, but I can't find any prices as they don't appear to have any distributors in the U.S. I didn't get any hits on eBay either.

Also, the VA series appears to be too large to fit under a Miata seat. I could probably get the RA 275 under there, but none of these would fit in the tunnel from the trunk to the passenger cabin.
  • VA 210 - 2x100watt @ 4ohm. 480mm x 295mm x 66mm (18.8" x 11.6" x 2.6")
  • VA 250 - 2x50watt @ 4ohm. 237mm x 295mm x 66mm (9.3" x 11.6" x 2.6")
  • RA 275 - 2 x 75watt @ 4ohm. 234mm x 188mm x 42mm (9.2" x 7.4" x 1.6")
  • RA 475 - 4 x 75watt @ 4ohm. 325mm x 188mm x 42mm (12.8" x 7.4" x 1
  • RA 220x - 2 x 200watt @ 4ohm. 325mm x 188mm x 42mm (12.8" x 7.4" x 1
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Old 3rd April 2007, 10:10 PM   #6
MadMutt is offline MadMutt  Australia
diyAudio Member
Join Date: Nov 2006
Before fully reading your reply I WAS going to say they also have the 'RA' series.

I do like (alot) that you are aiming for front first (at last a sensible car audio thread).

So my suggestion is;
Decent head unit (you've already got that one sorted)

Feed the front rca out to a four channel with built in xover.
Gives the option of bridging for two fronts OR four way active front.

Feed the rear rca out to a two channel amp with built in xover.
Gives the option of bridged for single sub with one v'coil, or dual coils, etc.

I prefer multi channel amps for their added versatillity.
Not a believer in mono blocks for car.

For the amps.
If the celestras are to big, maybe try findng some of the earlier soundstream amps, "Little angina" and the like spring to mind.
You have to remember that any amp with real rms ratings will be a reasonable size due to heatsinks.
I haven't heard the celestra's but from what I've been told they are quite amazing.
Think of audison nakamichi etc and put the celestra above that.

For pricing on the celestra's, forget the va's unless your rich.
Have a look here for an idea -->http://www.chriscrystalcraft.com.au/N.S.E.W.htm
I've bought some home audio bits from him, and he's always happy to answer questions.

Infinities are clean but lacking bottom end.
I would suggest you have a listen to;
ADS, AVI, Boston acoustics.
They should all have far better extension than the infinity's.

If boot space is a concern (should be, the mx's boot is tiiiny) have a very close look at the front doors, maybe you could fit a three way in there ?
Say an 8" in the factory spot and a 4/5" two way up higher.
Being in the door you probably couldn't run the 8" down too low without problems.
I imagine unless you make a small enclosure for the 4/5" 'mid' it would affect them too.

For the sub try sending 'car audio and electronics' an email, see if they have a copy or info on that mx-5, I think it was around 1995 ish.
It was a system done by a shop for a customer, wasn't a show car, just a good sensible system.
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Old 3rd April 2007, 11:57 PM   #7
maharashii is offline maharashii  United States
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Join Date: Apr 2007
Your guy in Australia doesn't have the Celestra RA series on his page. The others are way too expensive! I still can't find anything on these amps in the U.S.

Regarding my front stage, i think my ultimate goal would have been to have coaxial mids custom mounted in the kick panels, midrange/mid-bass in the stock door locations, and tweeters in the stock door tweeter location. I'd want to control that with full active crossovers and two amps (a 4 channel and a stereo) or with 3 stereo amps.

Sadly, I can't afford nor can I fit all that equipment in my car.

That brings me to a couple of key decisions:[list=1][*]Component or Coax?[*]If coax, I'll go with 6.5". If component, should I get an 8" woofer?[*]If components, active or passive crossovers?[/list=1]

I don't know how well to interpret the specs on various brands of speakers, and I'm hesitant to rely on an audition since they never seem to sound the same in my car with my amp as they do on the sound board.

That said, I'm looking for someone to say to me:
"Maharashii, I am an audio nut, and I have done my research, and I have found that XYZ model speakers have great specs and sound great with ABC amp."

The problem is that so far, people have been recommending setups that cost >$2000 when all I plan to spend on the speakers/amp is $600.
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Old 4th April 2007, 02:02 AM   #8
MadMutt is offline MadMutt  Australia
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Join Date: Nov 2006
We'll if you can't find it in the US I guess it doesn't exsist

He does actually, you didn't look very hard.

Go to his home page, click on buy car audio, scroll down maybe 10 cm's.
It's under the cheapy amps, and above the VA series amps.
Copied from his site

"RA150x - Mono Block - $790 - 234x188x42 - 1.4Kg

1 x 150W rms into 4 ohms
1 x 240W rms into 2 ohms
500W DC (@12V) high frequency switching power supply
Bessel linear phase and low noise filters
High pass (12db/oct) and low pass (18db/oct) are separately adjustable from 50hz-250hz
High pass output for external amps
No aluminium (electrolytic) capacitors or mechanical switches in the signal path
Very compact outline, with integrated cooling fan. Fine chromed and polished finish.

RA275 - $770 - 234x188x42 - 1.3Kg

2 x 75W rms into 4 ohms
2 x 120W rms into 2 ohms
1 x 240W rms mono bridged (into 4 ohm);
Tri-mode operation (mono + stereo without any switches or adapters)
500W DC (@12V) high frequency switching power supply
Adjustable bass boost @ 40 hz
No aluminium (electrolytic) capacitors or mechanical switches in the signal path
Very compact outline, with integrated cooling fan. Fine chromed and polished finish.

RA475x - $1,000 - 325x188x42 - 2.3Kg

4 x 75W rms into 4 ohms
4 x 120W rms into 2 ohms
2 x 240W rms bridged dual mono
Tri-mode operation (mono + stereo without any switches or adapters)
Bypassable low-pass and high-pass crossover - Fully independent in tuning (50hz-3.5Khz)
Perfect for use as sub & low-mid / low-mid & high-mid / high-mid & tweeter
Two independent 500W DC (@12V) high frequency switching power supplies.
No aluminium (electrolytic) capacitors or mechanical switches in the signal path
One of the more compact 4ch amps on the market. Fine chromed and polished finish."

As for someone saying buy xyz speaker, that's the best way to get something you don't like.
Everyone has their own opinion as to what sounds good.
True demo boards do differ in sound, especially once they are in a car.
Demo boards are only ever good for camparisons.

If your lucky you might find someone that will let you put one of your speakers in their board.

To me what you've got in mind for placement etc will only give muddled confused sound stage and terrible peaks and dips.
"coaxial mids in the kick panels"
"midrange/mid-bass in the stock door"

tooo much, go back to basics.
Two channels, two tweeters, two mid-bass, maybe a sub.

I am somewhat of an audio nut (Au$9,000 worth in the car not including labour)
It has a head unit, cd changer, electronic 3 way xover, a 4 channel feeding 6.5" components in the front doors, and a bridged two channel feeding a single sub.
Thats it.
Two amps, five speakers.

An 8" and tweerer just won't cut it.
The spread in frequency range is to great.

If thats your budget, well I do know stuff in the US is cheaper than here.
Is that a final budget ?
or is that what you have right now to spend ?

Find the speakers first, then worry about an amp.
You listen to the speakers, these will be the biggest single factor to your end sound quality.
Hi-end speakers should have decent sensitivity, that means you will need less power to drive them = less need for an amp.

If someone says "get these speakers they are the best" then I'd be worried.
How do they know what sounds best to you ?

Firstly, what are your music tastes, do you like it loud, do you want to spend as little as possible, do you want the best regardles of having to strip the interior of the car and rebuild it.

There are too many variables.

YOU are the one that has to listen to them.
YOU are the one spending the money.
YOU are the one that has to live with them.

Hint, go to a proper car audio shop, take a disk or two of your own, ask to hear the best they have, don't worry about price, then work your way down till you hit what sounds unacceptable to you.
THEN worry about price.

Maybe find a mazda club and see if you can go and listen to what they have done in their mx's.

EDIT, typos...
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Old 4th April 2007, 02:53 PM   #9
maharashii is offline maharashii  United States
diyAudio Member
Join Date: Apr 2007
Thanks again for the feedback.

$600 USD is what I am willing to spend on the front stage, initially. Some time in the future I might be willing to get a better crossover but that's only if I can afford it and it will provide significant improvements over the built-in crossovers that come with the amp.

I am thinking also about a sub. My budget for that will likely be around $600 USD. That would include the amp, the sub, the box, and the wiring. This is off in the future, after I've got my front stage sorted out.

Short answer, I'm going to put about $1200 USD total into the car's audio, and I have about $600 available to spend now.

Music Style
My music collection is pretty varied.
  • Hip Hop (Blackalicious, Roots, Real Elements, Jurassic 5, Spearhead) but I don't want rattling bass that is heard from hundreds of meters away.
  • Rock music (Rage Against the Machine, Tool).
  • Some electronic music (Bjork, Morcheeba, DJ Shadow).
  • Latin music (salsa), but NOT Reggaeton
  • Jazz (Charlie Mingus, Herbie Hancock, Medeski Martin & Wood)
  • Reggae (the Marleys, Peter Tosh, etc) and some dub / dance hall.
  • American country & western (Willie Nelson, Merl Haggard, BR5-49) and bluegrass

I also listen to a lot of talk radio in the car, so the ability to shut off the subs is important (this I can control via teh sub channel coming out of my head unit).

I guess if I were to choose a single genre that I would tune my music environment too, it would be the jazz music. Make my Medeski Martin & Wood sound fantastic and everything else will follow.

Regarding Amps
As for the Celestra, the least expensive (RA 275) is over my budget even factoring in the exchange rate. I'd also feel better about purchasing from a manufacturer that has distributors in the U.S. for warranty purposes, etc. I'd consider buying one of those amps used, but new is just too rich for me. There is a slight chance that I will find myself working in Melbourne at some point this summer. Maybe I could find a used one when I get there ...

Any other amp suggestions? Soundstream is repeatedly suggested to me as being a well regarded amp, due to the signal-to-noise ratio and the damping factor. However, it is gigantic, and I'd much rather have something smaller.

The Speakers
Regarding speakers ... I think I will focus on a 6.5" component set, or perhaps a 6.5" or 6x8" coax set. That should cover the frequency range better than an 8" speaker would, correct?

I will take your advise about auditioning speakers. Unfortunately, many of the brands that I am interested in (DLS, Dayton, etc) are not available in shops around here.
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Old 4th April 2007, 08:56 PM   #10
JCoffey is offline JCoffey  United States
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Join Date: May 2003
Location: Atlanta, GA
www.mmxpress.com has a deal going on that is pretty hard to beat. THey have CDT components, plus a set of rear fill coax, PLUS their imaging tweeters and attenuator for $350 for everything. I've been a diehard Dynaudio speaker fan myself, and listened to the CDTs and loved them so much I've installed them in two other cars. I still love my Dyns, but for those that cant shell out that much for a set of components, the CDTs are very hard to beat. Very nice sound, great power handling, and with everything else you get with it, a hard price to beat.

You and I have pretty similar tastes in music, and I'll be honest with you, will all the different brands I've listened to over the years, Dynaudios and CDTs in the order are my favorites. But since the Dyns alone would probably eat up your budget, not including the amp and everything else, I say CDT, and I think with that combo deal they have going on you'll be blown away for the price. I just wish I had the money to get a set myself right now. Damn I miss my Maxima with my Dyns, and Tube Driver amps
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