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Joe X

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Posts posted by Joe X

  1. Your net box volume is too high, it will play very peaky and lower sound quality (higher group delay), 2 net is maximum, port area 28-29 square inches is more than enough, larger port area than that is useless, the port gets longer and your external box size gets unnecessarily big, the longest port length I recommend is about 40 inches to avoid in-bandwidth port quarter wave resonances. 

     

    I have found that with skar subs their larger size box recommendation is about right, unlike many manufacturers that suggest tight enclosures than what they should because most people prefer smaller boxes.

     

    So 2.0 cubic feet net with 29 square inches of port area tuned to 32-34Hz is what would be my suggestion.

  2. Ok, you should find your maximum clean signal volume of your head unit with the DD-1,  at the RCA output of the LOC you should make sure that the "maximized" light is not blinking, should be completely off, the output voltage of the LOC should never be set above the input voltage of the amp, I guess I will agree that 5V Rms that you measure with the multimeter should be fine, Then you use the DD-1 connected to the amp output and set the amp gain making sure the DD-1 shows no clipping.

     

    If you use bass restoration available on the LOC test engaging in it during the gain setting procedure, making sure no clipping ocurrs.

     

     

  3. 10 hours ago, Chris423 said:

    I need help I haven't even hooked my subs up yet it's just my RCA jacks power and ground wire and remote wire as soon as I turn on the remote bass knob the clip light comes on and I'm not getting anything out of anything from the amp idk what I'm doing wrong please help

    Make your own thread, disconnect the RCAs and set the amp gain to zero and turn on again, hopefully no clipping will be present, also disconnect the bass knob if you use one.

  4. Open up the rear deck to let sound waves into the cabin. That is going to be half of the fix.

     

    Would need all the details of the box design you have (all internal and external measurements)  to tell you if the box is a problem but 2 cubic feet net is pretty standard  and should work, the amp is a little weak but nothing that would make a great difference.

     

    If opening up your rear deck is not enough I would go two 12s, probably better ones if possible.

  5. That's correct but bear in mind that it is just a rule of thumb and it may not be adequate in a number of circumstances, for example:

     

    1) you are applying a lot of power.

    2) suspension characteristics of the sub.

    3) box volume / port area.

    4) your actual tuning is not what you think.

    5 ) audio processors specially if improperly set.

    6) many others.

     

    A better way to get your SS frequency is measuring your actual tuning of the box you built and software modeling checking the excursion plot and making sure your excursion stays below Xmax.

     

     

  6. If you are looking for sound quality probably you want Mosconi, Arc Audio, Helix or such kind of amplifiers specifically made for sound quality.

     

    But if you insist on getting non sound quality specific amps like those you mention then in my opinion pick the cheaper solution, the two jp34ab,  class AB amps.  Usually class AB amps outperform standard class D amps in sound quality and it seems to be the case here as the AB option  has about 10 times less THD as the class D if you look at the specs.

     

  7. If what you want is some low end AND not to have a bass less system your setup will probably do.. or maybe you will be back as it often happens. I always suggest people to get a large enough system for the vehicle in question mostly to help avoid them go multiple upgrade cycles which are more costly in the long run.

  8. So here is a suggestion, power: to sub(s) rated, amp subsonic filter to 28Hz, minimum port clearance 2 1/4", figure is just an assembly guide:

     

    NOTE: If building outside you need to build a cardboard dummy box to test fit in it's way inside.

     

    NOTE: box ideally suited for sedan / hatchback

     

    lst.png

     

     

    1x12-SFPF-DB.png

     

  9. 29 minutes ago, Banditnib said:

    Oh okay, I think I may need to go back and double check my grounds and my connections. I did use a wire brush on my drill and got all the paint where my ground is. But you never know! And that’s my bad I forgot to mention that I do in fact have the big 3 done as well. Thank you for the advice! Once I get the chance I’m going to check this all out

     

    Only if your scope connected to the amp POWER  input terminals show sudden voltage drops that go below 12.5 volts, if you don't have such drops you don't have to do nothing.

     

    Best of luck and if you have any questions let us know.

     

  10. One possibility is that your subs are still on the break in period and need a couple of weeks for the suspensions to loose, yet you can use the scope to see how stable is your input power at the amp terminals,  even If the voltage drops for less than a second to less than 12.5V you can be having issues, those full bridge amps are a problem anytime your electrical is not perfect, even if your ground is not exactly great or any connections are not so tight problems can result even if your electrical components are good, if you did not do the big 3 you should do that immediately.

  11. 10 hours ago, sweetchuck said:

    I have an Alpine MRx-V70 amp (5 channel amp).  The mono channel is 250w RMS at 4 ohms.  If I buy an Alpine SWT-10S4 and put it in a .50cu ft truck box, will the amp power it?  I know its under powered, but I really don't want to buy a new amp, and I've been scared of the sound quality to go with the 2 ohm version.  Thanks for any feedback.

    You will not experience loss of sound quality on the sub by running at 2 ohm, THD+N is rated the same at 4 and 2 ohms and you will be driving the sub closer to what it expects.

     

    Honestly only cheap amps with deficient power regulation could perform worse when being used on a lower impedance load, Alpines is not the case, it could run hotter in any case if pushed hard, you prevent that with proper installation with great ventilation and maybe a fan nearby just to make sure if it became necessary.

  12. 2 hours ago, BFunnY6t9 said:

    Yeah but it's not the power that I'm going for the subs hit different at different ohms I believe. I always thought that the 2 ohm overall load sounded better than a 1 ohm. 1 ohm hits deeper base but the 2 ohm seems to hit a wider spectrum of bass than just the 1 ohm.  Its for rap music and I always thought that the 2 ohm sounded better. But from what I've seen I can't get a two ohm subwoofer to pull two ohms off of that amp unless I use both channels but then they're only going to get 750 each. The subs I want to use are 1400 RMS so I still want to get the full power of my amp.

     

    Actually no, if you wire coils in series you get 4 ohm, one sub per amp and you will be sourcing 1000W to each sub nominally (look at the table I left you above) but since rockford fosgate are under rated I am pretty sure you will be getting like 1200W to each sub.

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