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Help Tuning Subwoofer (Sound Ord. B-8PT) with Alpine HU

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Help Tuning Subwoofer (Sound Ord. B-8PT) with Alpine HU

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Hi all,

This is my first post, so go easy!!!

I have a 99 GMC Sierra with an Alpine CDE-9846 head unit (CDE-9846 description). I installed Kicker DS65 speakers in the doors (DS65 description)

I also recently purchased a Sound Ordnance B8PT (B-8PT description)

I have had one heck of a time getting it set up. My chief complaint is that the EQ in the HU is very basic, and does not provide a good range of options. However, I noticed I'm missing the entire bottom end. I can hear the subwoofer, but it's not nearly low enough. Im missing critical pieces of the bottom end, I can't even hear melodic bass riffs in my drum and bass music (for reference, it plays perfectly well via home system, headphones, and through my Honda Accord system w/stock HU, Kicker KS65 components in the front, and Kicker KS69s in the rear deck). The Kickers in my car blow away the truck system.

Thing is, my music sounds fairly normal (so I think everything is hooked up correctly), but it's been exceedingly difficult to tune. My biggest frustration is that the Alpine HU has these "centers" around certain frequencies, and won't give me decent sound.  The subwoofer is connected via the switchable pre-amp RCA output from the Alpine.  When I tweak the 'subwoofer' level, it responds.  And when I tweak the 'bass' level it also responds.  I would have thought that the overall system bass and treble adjustment wouldn't affect the sound coming through those RCAs?

I'm at wits end figuring out how to adjust/tune it properly. Any ideas? Here are my current settings:

Alpine settings:
- bass: 80 Hz, +4 level
- treble: 10.0 kHz, +7 level
- subwoofer: +10 level

Subwoofer settings:
- level: almost 3/4 max
- boost: 3 db (out of 12)
- frequency: 100 Hz
- remote level: 1/2

Thanks in advance!

Jason 
Spin Doctor 

2005 Honda Accord: Kicker KS6.2 (front), KS69 (rear)
2013 Mazda CX-5: Bose 9-speaker Centerpoint sound system

All Replies
  • Hopefully you have the RCA output in the head audio setting switched to subwoofer ?

    Forget the treble for now, it don't affect the S/O.

    Bass center at 80 or 100 hz. I would try the most narrow setting. This will affect less frequencies above and below the 80 or 100 hz. Bass level +10.Subwoofer preamp output (not the S/O. in the head menu still) +15.

    On the S/O, level about half, freq about half, bass eq 0db, play with the phase. Remote level full.

    Now see what you have. I have this same powered sub in a small extended cab truck. It shakes the mirrors, thumps my back, and has great bass guitar musicality.

    I'm thinking maybe you don't have the RCA output from the Alpine set to subwoofer.

     Also, since you don't have a highpass filter for the full range truck speakers, there is a chance you are experiencing some phasing and/or frequency cancellation issues and it is affecting the percieved bass response from the S/O sub/amp. Why I said to play with the phase knob on the S/O. It is nice because it don't have to be set at 0 or 180 only, but anywhere in between, which can help. Make doubly sure also that all your polarity is correct, including the red and white RCA outputs from Alpine to S/O, and your speakers.



    [edited by: GLH at 10:45 AM (GMT -5) on Fri, Apr 27 2012]

    GLH Geeked

  • Wow, excellent advice!  I have experimented with a couple similar settings, I'll have to try your recommendations this afternoon.  I am sure that the RCAs are correct, and I do have the subwoofer set to "on" in the setting menu.  I did try 'widening' the bass center band, but it didn't seem to do much.

    I think the most confusing part is how the overall 'bass' level affect both the full-range speakers and the subwoofer.  I would have thought the two would have been independent.

    I'll try things out tonight, but I'm hoping I get some nice kick in the low-end from this speaker.  I was surprised by how much of the low-end is missing (seemingly 100 Hz and below is absent from my music).  If that's the case, it may be that this sub is not performing as spec'd (down to 40 Hz).  I'd hate to have to replace the HU just to check out my theory, but perhaps something with a wider range of EQ adjustment is just what I need?

    Thanks again, I'll follow up soon.

    Jason 
    Spin Doctor 

    2005 Honda Accord: Kicker KS6.2 (front), KS69 (rear)
    2013 Mazda CX-5: Bose 9-speaker Centerpoint sound system

  • You might think your full range Kicker speakers are the *** for bass, alot of peeps do. I have experience with them and know they aren't. A good option since you don't have a highpass filter nor an amp for them is to use 150 hz bassblockers on them. When you get it all tuned/EQ'd well, all the sound will seem as tho it is originating close to dash center, optimally.

    Another thing you should try is to set all your EQ, sub level, etc. in the head where you want, then with the S/O RCA's disconnected, turn the volume up until the Kickers distort, then down a notch at a time until they stop distorting. Now turn off the power, reconnect the S/O RCA's, set the S/O how you want, listen to a well recorded bass heavy song, turn up the level on the S/O until it sounds good. You should do this with the engine started and the doors and windows closed.

    GLH Geeked

  • I don't have anything useful to add to this, just something caught my eye:

    SpinDoctor15
    Hi all,

    This is my first post, so go easy!!!

    This post should go in the "First Post Hall of Fame"! You gave all your equipment with model numbers, links to all of them, precisely described your problem, even listed your current settings.  Well done! 

    You should see some of the other "first posts" we get here.  Goes something like this:

    YO I got 2 12S AND THERE SUPER LOUD BUT OTHER DAY THEY WERENT SO LOUD 1 WAS LIKE 4 TIMES LOUDER THAN OTHER AND ONE SMELLD AND SMOKED WATS WRONG??????? OH I HAVE 12S HOOKD UP TO 5000 WATT AMP AND CAP IF THAT HELPS THAKS

    So thank you for taking the time to type like a human, and welcome to the forums!

    1998 Honda Prelude, Pioneer DEH-P9400BH + Sirius tuner, Kicker KS6.2 front components, Kicker KS6930 rear speakers, Alpine MRP-F300 for speakers, Alpine SWR-1022 in ported box, Rockford Fosgate Punch 501s for sub.

  • some of your issue may be due to improper phasing.  correct phasing is important!!!

    from what i've read so far, the only phase correction available to you is the "reverse mode" for the subs and a bit of crossover frequency selection choices (crossovers impact phase). you may also be able to move the sub, which will also affect phasing.  reverse the phase, and see if that helps (but that will affect every other frequency in the sub range, so some frequencies may become suddenly louder, whilst others will be weakened.

    in a perfect world, a single speaker with all the component speakers aligned on the same plane that played the entire spectrum of sound would eliminate phasing issues.  home audio has this (tweet, mid and woofer are very close together), but car audio does not (at least not as good, anyway... you usually need to add a sub somewhere in the trunk/cargo area to car audio systems).  that makes things tricky, cuz a sub usually ends up way back in the vehicle, while the primary speakers are located up-front.  so that presents a delay...  cuz sound takes time to reach your ears compared to something like light, which is virtually instant.  sound is slow... i learned this in grade school while at recess.  the kid that got in trouble that day had to clap erasers as punishment, and i noticed that the sound had a great delay from the time i saw the erasers clap to the time i actually heard the clap.  matching subs with front speakers requires some timing consideration.  otherwise, they may be completely out-of-phase at certain frequencies and you can end up with nearly zero output as the front speakers work against the sub.  cross-overs can be a big aid here, but there will always be some overlap in freq response between the primary speakers (preferably the front speakers, but that's another argument) and the sub. 

    you've really got to play around with those filter frequencies.  i haven't read a "correct" way to do it, it's usually just trial and error.  really helps to have test tones and an SPL meter, but sometimes the best possible equipment is your own 2 ears!  after all, that's the equipment that matters most...

    the way i do it is to first set the front speakers.  the front speakers should always be the priority in a SQ system (where sound quality is a matter of import).

    i get them sounding as nice as i can, and then i add the sub.  sometimes it works right off the bat, but not usually...(well, never to be perfectly honest)  you've got to play with the sub crossover settings and sub position a LOT.  and if you ALSO adjust the front speaker crossover settings, it squares the permutations (meaning it becomes a mathematical nightmare!).  but you don't need to understand math to know what sounds good... thank goodness!

    i might be more confusing than helpful, so i'm gonna pause here and hope you are kinda getting me.  you stated some very technically correct things earlier, so i don't want to insult you.  i'm good with subs tho, just i tend to go overboard and give a half dozen ported box designs only to find out the OP just wants a sealed box!  box design probably takes double the time as actually building the box!

     

  • Thank you all for the great inputs.  I'm happy to have joined a community where folks actually KNOW what they're talking about!

    So, I've tried a couple things today, none to great success...

    GLH: I made all the adjustments according to the settings you recommended.  Most of the adjustments were good choices, however, the one that just didn't work was the Bass level set to +10.  It made everything completely muddy and overloaded.  Furthermore, the bottom end (sub 200/100 Hz or so) is still absent.  So, I dialed bass level back to a comfortable +4 and left all the other settings as you prescribed.  Thanks for the good suggestions.

    J Ro: I appreciate the thought you've put into my issue as well.  I did play around with the phasing, and I know how it's responding as I change it, yet I've determined that this is definitely not the issue.  Whether I sit in the driver's seat or if I hop in the back of the cab and get up-close with the sub, it doesn't affect the loss of the low frequency.

    I'm still hung up on whether/not the 'bass level' should affect the output of the sub.  When other people tweak their system, does the 'bass' EQ setting affect the sub? (outside of the 'subwoofer' EQ setting?)  When I set my 'bass' level to 0, all bass disappears, including the subwoofer.  That's what is getting me confused.  I would think that the full-range speakers would miss the bass, but that the sub would keep on kicking?  That's also why the bass level +10 drowned all the sound in muddy bass.

    One additional observation: it doesn't appear that the crossover frequency is affecting the sub.  I'm still getting higher tones out of it (and am missing the low notes) even with the freq. range adjust down to 80 Hz.  It doesn't seem to be impacting the sound.  Since my full-range speakers don't sound good with this Receiver, and the subwoofer doesn't seem to be operating properly with this Receiver, could my problem really be the Receiver?!

    Jason 
    Spin Doctor 

    2005 Honda Accord: Kicker KS6.2 (front), KS69 (rear)
    2013 Mazda CX-5: Bose 9-speaker Centerpoint sound system

  • SpinDoctor15
    One additional observation: it doesn't appear that the crossover frequency is affecting the sub.  I'm still getting higher tones out of it (and am missing the low notes) even with the freq. range adjust down to 80 Hz.  It doesn't seem to be impacting the sound.

    could it be that you don't have the SUB pre-outs connected to your amp?  adjustments to the LPF for the sub should have a noticeable impact.

  • This HU only has one set of RCA outputs, and I'm sure the polarity (red/white) is correct.  I'm wondering if the 'switchable' nature of this channel is actually causing it to be amplified from the HU, rather than clean or un-amplified.  Perhaps I don't have a good understanding of how this actually works?

    I'm going to try another experiment tomorrow.  I have an iPod with music loaded where I know the bass pattern.  I'll connect it to a cable I have with stereo mini-jack on one end converted to RCA red/white on the other.  I'll then connect it directly to the sub and listen for the low tones I expect.  If I hear them (knowing the rest of the music will be absent), then I can assume that the sub is capable of handling my music the way I expect, and that the HU is just terrible.  If I DON'T hear it playing nice low notes, then I'll wonder if the sub is even capable of the stated 40 Hz on the low end of the range.  I'll report back soon ;-)

    Jason 
    Spin Doctor 

    2005 Honda Accord: Kicker KS6.2 (front), KS69 (rear)
    2013 Mazda CX-5: Bose 9-speaker Centerpoint sound system

  • SpinDoctor15
    I'm going to try another experiment tomorrow.  I have an iPod with music loaded where I know the bass pattern.  I'll connect it to a cable I have with stereo mini-jack on one end converted to RCA red/white on the other.  I'll then connect it directly to the sub and listen for the low tones I expect.  If I hear them (knowing the rest of the music will be absent), then I can assume that the sub is capable of handling my music the way I expect, and that the HU is just terrible.  If I DON'T hear it playing nice low notes, then I'll wonder if the sub is even capable of the stated 40 Hz on the low end of the range.  I'll report back soon ;-)

    gotta say WOW!  you're a natural at fault isolation!  definitely try that, and let us know what you observe.  it would indeed isolate the HU as the issue if sending the signal to the amp directly from a known good source resolves the issue.  kudos!  i may have suggested the same thing myself...

  • SpinDoctor15
    This HU only has one set of RCA outputs, and I'm sure the polarity (red/white) is correct.  I'm wondering if the 'switchable' nature of this channel is actually causing it to be amplified from the HU, rather than clean or un-amplified.

    skimmed over this again, and if your pre-amps (or RCA outputs, or line-level signals, or low-voltage outputs... all are terms that mean the same thing) are switchable, you might simply need to switch them.  i know what you're thinking right now... "thanx, Captain Obvious!" but just want to be thorough.  be nice if all you had to do is hit the right button!

  • Hehe, I wish that too!  I have attempted to switchitbck and forth but it doesn't affect the sound much.  I can hear a difference hen it amps the front speakers vs the sub, but it isn't large, and doesn't drastically affect the sub freq range.  Will try my iPod trick this morning and report back ASAP!

    Jason 
    Spin Doctor 

    2005 Honda Accord: Kicker KS6.2 (front), KS69 (rear)
    2013 Mazda CX-5: Bose 9-speaker Centerpoint sound system

  • The RCA preamp output must be switched to subwoofer output, and that output connected to the sub amp.

    Switchable Preout: The preamp outputs can be switched from front channel outputs to a non-fading subwoofer preamp output with a variable level of 0 to +15. When the subwoofer is activated in the Setup menu, the preout is switched at the same time. When the subwoofer is deactivated, the preout is switched back to a front channel output.

    GLH Geeked

  • Great first post - it's usually about the 4th post that we find out about the 5,000W amp. Devil

    The EQ settings typically WILL affect the subwoofer RCA's as well.

    You really have PLENTY of EQ control with the Alpine HU, but they can be MUCH trickier to setup than say setting a Pioneer HU to "Powerful".  If you play with the settings, you should eventually get the sound you want.

    I would also recommend downloading some test tones and burning them to CD and testing them to see what plays on the subwoofer and what plays on the head unit.

    There should be a DRASTIC difference between the pre-outs in FRONT and SUB mode - although not as much if you have the LPF on on the B-8PT and the HPF off on the HU.

    Crutchfield's Tech Support may be able to help also (assuming you bought new from them).

    Hope This Helps!!!

    Anyone else have suggestions?

    2002 Ford Focus JVC KD-A815 Sony CDX-GT410u Sony XT-100HD HD Tuner Stock speakers, no amp, no subs

  • Thanks again for all of your help.  I have spoken with Crutchfield customer service and gone through multiple setup options.  It appears I'm just not getting the low-end from this sub that I expected.  I'm disappointed since the frequency-range published in the specs show it will reach 40 Hz.  I do have a test CD (The Ultimate Test CD), and the 40 Hz tone is audible, but barely there.

    This is also reflected in the music I've been playing.  The Apline HU is set up about as near perfect as I can get it.  I also disconnected the RCAs and plugged in an iPod (ran mini-stereo to RCA output cable straight into the sub).  I received the same musical response from the iPod as I did from the HU, which means that the sub-100 Hz tones were weak and lacking in similar passage of music.

    I spoke with a Cust. Service rep, Kevin, about other options.  My new plan is to get the nicely-priced Q-Logic/Q-Customs dual-10" box, plant a nice 500W 2-Ohm amp in the back and run 2 SVC 4-Ohm subs in parallel.  Should give me the low end and the oomph I'm looking for.  Thoughts on that setup?

    The Q-Customs box (link to product) allows for a top mounting depth of 5" for the subs.  These guys all fit the bill (comparison), any feedback on my potential choices?  I'm would LOVE to get some JL Audio in my truck.  I have owned a Polk sub in a previous truck and was largely unimpressed when feeding it 300W from a Kenwood 2-ch bridged amp, so I'm not thrilled to look at Polk again, but I'm open to the idea.  Thanks in advance!



    [edited by: SpinDoctor15 at 10:26 PM (GMT -5) on Thu, May 3 2012]

    Jason 
    Spin Doctor 

    2005 Honda Accord: Kicker KS6.2 (front), KS69 (rear)
    2013 Mazda CX-5: Bose 9-speaker Centerpoint sound system

  • Your expectations were too great.

    I do not believe you correctly understand how speaker specifications are rated.

    A person looking for the kind of bass obtained with a 500 watts dual subwoofer setup should not be looking at an 8" powered sub.

    Mine works great for the purpose I am using it. It is set to lowpass at 80 hz and is doing so nicely. The rearview mirror trembles and the bass is not distorted.

    GLH Geeked