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Speaker Impedance on the 328?

Discussion in 'Technical Q&A' started by Tod328gts, Mar 8, 2004.

  1. Tod328gts

    Tod328gts Formula Junior

    Jul 23, 2003
    625
    River Forest, IL
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    Tod Whitmore
    Well, i know this is a very controversory issue, having a radio in a Ferrari, but, the one in my 328 finally crapped out. So, i figured, just replace it and the speakers too. I noticed the 328 has 4 speakers, two tweeters in the dash and two 6.5" in the doors. I noticed that each set of speakers are tie together in Parallel. I am hoping that each speaker is atleast 8 ohms to make the total impedance at the radio 4 ohms. Does anyone know for sure ???

    Unfortunately, new speakers are all 4 ohms now, i am only planning on replacing the door speakers. so, with those in parallel with the dash tweeters, this may make them 3 ohms then at the radio. I would hate to over heat the Amp in the radio, so i may have to disconnect the dash tweeters for this or seperate them and wire them all into a 4-speaker setup into the radio...

    If anyone knows the correct impedance of the stock 328 speakers, that would help alot...

    Thanks in advance...

    Tod
     
  2. enjoythemusic

    enjoythemusic F1 World Champ

    Apr 20, 2002
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    Tod,

    Sounds like you already know what you are doing. Ferrari just tied them together, not even a capacitor (bass blocker) in the tweeter??? Weird. If it was me, i would get proper component speakers with external crossover.

    FYI: usually loudspeaker impedance is not a constant. It can vary by frequency. The rating is usually more a nominal versus a min/max impedance measurement. A pair of 4 ohm may be ok, though i'd play safe with a pair of 8 ohm if the wires are parallel. If they are in series, 4 ohm is fine.

    Hope this helps.

    Enjoy the Drive,

    Steven R. Rochlin
     
  3. Chiaro_Slag

    Chiaro_Slag F1 Veteran

    Oct 31, 2003
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    Jerry
    It's a great design - then the speakers get covered with carpet, lol.
     
  4. f355spider

    f355spider F1 World Champ
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    May 29, 2001
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    Hugh G. Rection
    I believe this is bascially a non-issue. Most car stereos are designed to handle a 2 ohm load. Most car amplifiers even give a 2ohm output spec. I would just select a nice quality 6.5" coaxial speaker and not worry about it. I did this and found the addition of the tweeter in the coaxial speaker really improved the imaging and high end a lot. Those tweeters in the dash are not so hot by today's standards.

    My understanding of the tweeters in the dash is they simply have a high-pass filter, that's all.

    If it concerns you, you could probably add a resister in line...
     
  5. Enzo

    Enzo F1 Rookie

    Feb 14, 2002
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    Pat Pasqualini
    Listen to Enjoythe Music he is the man when it comes to sound. If you are going through the trouble of installing a new head unit and speakers you might want to run new speaker wire. It will more than likely be a better guage and quality then what Ferrari put in to begin with.

    Pat

    PS. would really appricate Enjoythe Musics new avitar PM'd if the chance is there. Love those blondes.
     
  6. enjoythemusic

    enjoythemusic F1 World Champ

    Apr 20, 2002
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    Enzo (and all),

    Many thanks, yes, have MANY YEARS of audio (home and mobile) experience. Would suggest running new wires, heat shrink/solder wires together where applicable.

    NEVER use those CRAPPY "fold over" clips. NEVER!

    Frankly, never cared much about the radio/CD in the Fcar, but in the Honda i swear by the Nakamichi separates. HIGHLY prefer a silk soft dome tweeter over poly/titanium equivs.

    BTW: would never go to 2 ohms off a head unit. They generally use crappy amps within not meant for 2 ohm load. Better to be safe (8 ohm) than overheat the unit (2 ohm) IMHO.

    Enjoy the Drive,

    Steven R. Rochlin

    PS: Enzo, alas, no more pics :(
     
  7. enjoythemusic

    enjoythemusic F1 World Champ

    Apr 20, 2002
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    Dave,

    Sorry to disagree, but head units generally hate 2 ohm loads. As for resistor, that would LOWER the volume of a speaker/speakers, but not a proper solution IMHO.

    Now if you REALLY want to get creative, you could go with any impedance and use a converting transformer. Heck, make the transformer silver wired with awesome laminates :) i know a few guys who can custom wind such toys... for a price of course.

    But this way leads down the to the Dark Side of audio...

    Enjoy the Drive,

    Steven R. Rochlin
     
  8. Tod328gts

    Tod328gts Formula Junior

    Jul 23, 2003
    625
    River Forest, IL
    Full Name:
    Tod Whitmore
    Thanks everyone for your inputs... Looks like i will just replace the door speakers and go with that... Even it the impedance is 2 ohms at the head unit, i won't be blasting the music anyways, i would need a 800 W amp to get over the sound of the TUBI anyways... :)

    The current speaker wire and power/ground wires seem like a good heavy gauge currently, the speaker wires could be at least a 14-16 guage which should be more than enough... But i will examine the condition of the wires in the doors and determine then if i have to replace them..

    The next fun will be trying to replace the speakers in the doors now, replacing the radio was a piece of cake, i think puling the door panels may be a bit more messy. I did get the info from the resourse page on ferrarichat.com... I wish just the carpet area would come off instead of the entire door to get to the spreakers... HAH!

    Thanks again, i'll post some picture of my fun i had with this soon....

    Tod
     
  9. Tod328gts

    Tod328gts Formula Junior

    Jul 23, 2003
    625
    River Forest, IL
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    Tod Whitmore

    Steven,

    I agree with you there, that was my initial issue with this post, i didn't want to over heat the amp if the impedance got to be less than 4 ohms..

    In the 328, the tweeter in the dash and the door speaker are tied together in parallel, so, i am assuming they are both 8 ohm impedance then which would give the head unit a 4-ohm load...

    Thanks for your inputs...

    Tod
     
  10. enjoythemusic

    enjoythemusic F1 World Champ

    Apr 20, 2002
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    Tod,

    100% correct. Also, go to Radio Shack/Tandy and add a capacitor on the tweeter wire so the bass frequencies are rolled off and are not fed to the tweeters. You really know what you are doing, just trying to help my friend.

    Enjoy the Drive

    Steven R. Rochlin
     
  11. f355spider

    f355spider F1 World Champ
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    May 29, 2001
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    Oops, thought you were using a seperate amp....most can handle 2 ohms, no sweat.
     
  12. zan

    zan Formula Junior

    Nov 15, 2002
    537
    Boston
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    Mark M
    355 tweeters have a capacitor in series mounted to its connector.
     
  13. Tod328gts

    Tod328gts Formula Junior

    Jul 23, 2003
    625
    River Forest, IL
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    Tod Whitmore
    That was my guess too, even though it doesn't show it in the 328 wiring diagram is that there is probably a capacitor allready across the tweeter. Oh God, don't know if a want to add to the excitment and try to get to that tweeter, it looks like a big job, like pulling the entire dashboard out... Hmmmm????

    I'm dreding replacing the door speakers, the radio was a piece of cake to get to, i guess everything can't be easy....
     
  14. Verell

    Verell F1 Veteran
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    May 5, 2001
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    Verell Boaen
    A capacitor acts as a high pass filter, thus it must be in series (inline) with the tweeter.

    The 328 door panels are pretty much like the 308 door panels. About the same amount of work to remove as pulling a head unit.

    1)Remove the door lock knob by unscrewing it.

    2) Remove the arm rests
    The arm rests are held on by 3 10mm nuts: 1 in front of the latch release, 1 shortly behind it, & 1 towards the rear of the opening for the latch. Then there are 2 #2 phillips head screws on the bottom of the arm rest. 1 about half-way between the latch release opening & the bottom tip of the rest, and 1 at the very tip.

    3) Remove the trim screws
    There are 4 or 5 #1 phillips trim screws: 1 on the cover's edge just above the latch. The others are buried in the carpet in the bottom of the door & colored to match it. All are just inboard of the leather trim that runs around the outside edge of the carpet. Their locations are: About the middle of the door's outside corner. About 1/2 or 2/3 of the way from the outside corner to the speaker. About an inch towards the center of the door from the speake opening's inner edge. Front edge of the door about level with the center of the speaker opening. The panel should be loose al along the bottom & just hanging by the trim along the window. If it isn't, go find the trim screw that's still buried in the carpet.

    Like a lot of other things on these cars, the exact number & location of the trim screws seems to vary a bit.

    5)Remove the panel by lifting it upwards & slightly rotating the outside edge upwards along the door.

    That's it!

    Be careful when removing the armrest. Do NOT let it pivot out of position as the cover is stapled on & the staples can scratch up the door panel then it's a couple of days with crack filler & leatherique to get rid of them (don't ask). Also make sure you completely remove the screws before removing the armrest as they too could make a heck of a scratch.
     
  15. parkerfe

    parkerfe F1 World Champ

    Sep 4, 2001
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    Cumming, Georgia
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    Franklin E. Parker
    I had the speakers in my ex-328 replaced with ones from MBQuart with proper cross-overs and they sounded great. I used the same tweeter cover so after the install they looked the same as the stock ones.
     
  16. Tod328gts

    Tod328gts Formula Junior

    Jul 23, 2003
    625
    River Forest, IL
    Full Name:
    Tod Whitmore
    Hey Verell,

    Thanks for the help with the door panels, i will probably temp them in the next couple of days, first i will finish wiring the radio in, got some heat shrink today. The previous radion install they used these crimp connectors on the wire, i'm going to remove then and solder and heatshrink the wires now. Might as well do it right now...

    Then, after i get the interior back together i will start on the doors to replace the speakers there, hopefully the wiring is fine.

    Don't you hate it when a simple project sometimes turns into a huge can of worms?? HAH!
     
  17. Paul_308

    Paul_308 Formula 3

    Mar 12, 2004
    2,335
    Impedance is only like resistance when measured at one specific frequency. If you send a 4 ohm speaker the same tone as an 8 ohm speaker, the 4 ohm speaker will be marginally louder. But you aren't sending midrange and tweater the same stuff to play so it won't matter. From it's low to it's highest frequency, a speaker's impedance can vary 25:1 i.e. be from 1 ohm to 25 ohms. And that will even be modified by how you mount them. Athough there is an industry standard on how the measurement is performed, there is none on how to rate them. The manufacturer chooses a point on this wild curve which seems appropriate for his intended market.

    You want controversy, get into the guitar amplifier world and argue a about impedance of speakers used on a tube amplifier vs transister amplifierYou can't tell any impedance difference listening but they argue anyway.

    Related: The only way to harm a transistor amp is to short the output...the only way to hurt tube is have NO load. If you want real fidelity you will be using system matched speakers and not have a problem. Otherwise hook it up and enjoy it.
     
  18. enjoythemusic

    enjoythemusic F1 World Champ

    Apr 20, 2002
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    Paul_308,

    Fully agree about the varying loudspeaker impedance, but you CAN damage a solid-state amplifier if you use too low Ohm loudspeaker. It can cause overheating and lead to burning it out.

    As for tube amplifiers :) Have five tube amplifiers here including an OTL headphone amplifier for my Sennheiser HD600 cans.

    Enjoy the Music,

    Steven R. Rochlin
    http://www.EnjoyTheMusic.com
     
  19. Tod328gts

    Tod328gts Formula Junior

    Jul 23, 2003
    625
    River Forest, IL
    Full Name:
    Tod Whitmore
    IMPEADANCE, That is the reason i started this post. Steven and Paul_308 are both correct. Shorting the output of an Amp is the same as lowering the load resistance.

    It all depends on the type of amplifier used, some companies have thier own output amp stage that may have short circuit protection too. Unless you have the schematics of the amplifier, you need to be careful on hooking them up, like being sure you use the correct load that is specified for that amplifier.

    Anyways, got the radio installed and one of these nights i will replace the stock speakers, even though they do sound ok, can't really tell while the car is running with that new TUBI i put on.... :)

    I have some pictures i will post of my radio install, they are on another computer, will do later....
     

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