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4ch amp help

Discussion in 'Car Audio / Security / Electronic Accessories' started by AHHVTEC, Dec 24, 2011.

  1. Dual-500

    Dual-500 Well-Known Member VIP

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    Exactly, if the power line to the amp is running in parallel with the RCA coax it could magnetically couple with them to induce the issue.

    The amp may be unstable, but I think it's more an installation issue.
     
  2. AHHVTEC

    AHHVTEC Well-Known Member VIP

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    why yes they are the power wire and the rca cables are perty much side by side under the carpet all the way back to the amp
     
  3. AHHVTEC

    AHHVTEC Well-Known Member VIP

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    so im gonna run the wires away from each other so there not even close, but one more question, about where should i set the frequency knob at. ?
     
  4. CAFROG

    CAFROG Honda Minion VIP

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    Yes the RCA's and power wire need to not be next to one another and preferably as far away as possible.

    The low pass frequency......I like 80hz but if you midrange from other speakers are inferior or weak then you can go higher low pass frequency on the sub to compensate.
     
  5. AHHVTEC

    AHHVTEC Well-Known Member VIP

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    thanks man, what sucks about this amp is there is just a knob it dont tell you what your at you just have to guess at what frequency your at lol. so about half way you think
     
  6. CAFROG

    CAFROG Honda Minion VIP

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    LMAO is it old and the numbers disappeared or what? Just find a well balanced song (harder to find than you might think) and tune it

    "Holiday" by Madonna is well balanced and great for tuning unless it's too girly for you.
     
  7. CAFROG

    CAFROG Honda Minion VIP

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    Or does you deck have a crossover for a sub RCA output?
     
  8. AHHVTEC

    AHHVTEC Well-Known Member VIP

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  9. CAFROG

    CAFROG Honda Minion VIP

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    Middle of that frequency seems to be 80hz then.

    Your deck has only one pre-out and it don't seem to have a subwoofer crossover in it but the amp crossover should be fine
     
    Last edited: Jan 8, 2012
  10. Dual-500

    Dual-500 Well-Known Member VIP

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    Lauging about this one still, days later. :) Too girly!!!

    Funny, I did pro audio and lighting from the late 70's and through the 80's and used that song many times for sound check! DJ systems, club systems, stage monitors and FOH mains. :) Billy Idol singles were also great, and Der Kommissar, the enginsh version by After the Fire. All the Huey Lewis mixes of course and Sammy Hagar cuts from Standing Hampton, 3 Lock Box and VOA "I Can't Drive 55".

    You are right, Holiday is a good one, not only the composition of the song itself, but the studio work is superb.

    Another good one:

    One Way - Cutie Pie - YouTube

    http://www.youtube.com/watch?v=hIZSfPl2TzM

    A little circa 80's band I setup follow spots and staging (mics, monitors and monitor mixing console, signal processing) for in the Old Town Saloon in February 1988 just before "Welcome to the Jungle his the airwaves":

    [​IMG]
     
    Last edited: Jan 8, 2012
  11. Dual-500

    Dual-500 Well-Known Member VIP

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    80hz and lower crossover frequencies are typically used in home theatre systems with satellite subwoofers - I use 120hz for satellites personally and autosound for the most part.

    In autosound, they have somewhat bastardized sound and equipment design from the Ghetto Blaster crap that runs down the road making noise. I think the call it SPL competition or some such nonesense - just put a grenade in it and call it a day. Manufacturers have followed by designing and marketing equipment to fill the niche. i.e. super low crossover frequencies for the LF section.

    For SQ (sound quality), 120hz or higher crossover frequency is probably best - but, the optimum crossover point is really dictated by system design, driver selection, etc. Not just an arbitrary number. Many multi-amped professional systems (club and touring) cross over from LF at 200hz and sometimes even higher. Proper system design will have the LF and HF sections balanced in terms of Acoustic Power generation. Not 1000w on the bottom end below 80hz and 200w on the HF above 80hz.

    Not saying 80hz won't work ok. If the bottom end is robust and mids not so much, then I would suggest bring it up to 120hz. That will take some of the load off of the mids. Unless of course the intent is to annoy neighbors and such, then 80 or even lower will optimize the LF power band and available Hump Hump Hump. ;)
     
  12. AHHVTEC

    AHHVTEC Well-Known Member VIP

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    thanks guys youve helped me a ton, i normaly dont like to be spoon fed but i will retain this info for the future.i plan on moving the rca cables this teusday,and hope thats the problem and i will post up results.
     
  13. Dual-500

    Dual-500 Well-Known Member VIP

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    You bet - I've had fun with it bro. It got me thinking about the old days. Here's my 1st generation Mobile DJ system back in 1978 that got me started in audio. CAFROG hit a nerve with the Madonna "Holiday" suggestion - I used it many many many times for sound checks all over the place. Brought back some fine memories for me. Glad we could help you sir.

    [​IMG]

    That picture was scanned from a Kodachrome slide and scaled up 600% so it don't look so good. The large speakers on either side of the DJ Console are Altec Lansing A4's, they stood 84" tall and were loaded with a pair of JBL 2205 professional 15's per cabinet.

    Here's a better picture of the Altec A4 with the side wings on them. These monsters weighed 395 lbs empty - they rocked!

    [​IMG]
     
  14. Dual-500

    Dual-500 Well-Known Member VIP

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    CAFROG is spot on with the wiring proximity comments. It's tough to tell you exactly what will fix it - because it can be caused by a myriad of problems or a combination of problems or issues.

    He's spot on with the Sound Check suggestion too! Woke my brain up for sure. ;)
     
  15. AHHVTEC

    AHHVTEC Well-Known Member VIP

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    ok, ran the rca wires down the passenger side, remote wire down the center and hot wire down the driver side, with no change, and i noticed as i was touching the amp you could hear my fingers touching it through the speakers lol. so im gonna run a better ground and solider the speakers wires in the box good, and if that dont work i guess i will get a new amp.
     
  16. Dual-500

    Dual-500 Well-Known Member VIP

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    Yes ground is next. Also, it could be poor quality RCA lines. Don't need a $60 set of Monster cables, but maybe better than what's there now.

    It could also be the amp itself. Just now way of really knowing without the process of elimination via trial and error.
     
  17. CAFROG

    CAFROG Honda Minion VIP

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    If the power wire is away from the RCA's then they are not giving bad feedback (remote don't matter).
    Real crappy RCA's can be a problem but I have used cheap ones in Boat builds and had no issues.
    Good ground is important.......maybe even use some sand paper to get good contact with chassis.

    If its still horrible.....I think its the amp and she's seen better days.
    Does someone you know have a amp to test the wiring?
     
  18. AHHVTEC

    AHHVTEC Well-Known Member VIP

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    some of hes friends might, but none of mine does. im gonna give this last thing a go and if that dont work new amp it is. i think hes kinda itching and wanting a new amp anyways lol. i seen a planet audio 2 ch 600 watt at best buy, but im not sure if thats a good one or not im trying to fine one thats 150watts rms per channel and 300 watts max per channel and 4ohms
     
  19. Dual-500

    Dual-500 Well-Known Member VIP

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    What gauge is the wiring to the amp? That can also cause problems. Needs to be large enough to support the current draw. Sometimes the addition of the filter capacitor at the amp will do the trick.
     
  20. AHHVTEC

    AHHVTEC Well-Known Member VIP

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    i will have to double check but i believe its a 8 gauge, it came in one of those kits, i forgot the name brand but i do remember when i got it 8 years ago lol, that it was a good kit.
     
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