Subwoofers not as loud

BreadLord

Junior Member
Mar 28, 2018
17
0
Gaffney
Okay so about 8 months ago (give or take a couple months) I installed a setup in a 1965 Mustang. Upfront it has a yellow Optima and 120 amp alternator (yes, I know that needs to be upgraded and it will be). The head unit was an old Custom Autosound USA-1 (a real POS) but is now a Retrosound Detroit motor 4 (the head unit isn't as important but both are designed to fit the original dash with no cutting). I hoped a new radio would fix my issue but it didn't. Four Kicker (junk, in there when I got it) speakers in the cab powered by some four channel Kenwood. Then the subwoofers are 2 Alpine Type R 12s wired to 1 Ohm in a custom sealed box powered by a Hifonics BXX3000.1. I dont know how you guys feel about Hifonics but long story short it isn't the amp I clicked "buy now" for. Forgot the cubes of the box but it was within spec when built.

Anyway this setup used to be beyond loud enough (mainly older rock but the occasional rap demo for a friend) however one day I noticed the bass was quiet. With the bass knob, I have to max it out to get quiter output than 1/4  to 1/2 of a turn used to get me. Keep in my mind I set all my gains with an oscilloscope as well. Playing a test tone the subwoofers still seem to get very loud but when playing a song the four cab speakers usually overpower the bass, before it was the other way around. The sub amp has 1/0 guage wire and a bare metal ground to the chassis where a large bolt is located for the bumper. My RCAs measure 2.85-3v. The day the bass seemed quieter nothing had changed from the previous day. Solid connections to the amp, 1 ohm at the subwoofers (yes I checked everything with a multimeter), about 3 volts at the RCA, gains set with an o-scope (-5db), and I recently took out my box to reseal it and double check the subwoofer's wires as well as their suspensions. Everything seems to check out. I've been through the settings in my radio as well. The cab speakers are much louder than the bass. I'm open for any suggestion and willing to double check anything I already have. If everything seems to check out then why might my bass have gone quite to never return? 

As another note, the amplifier still pulls enough to get some voltage drop (headlight flickering). Before the bass went quiet, there would be no voltage drop when at a comfortable listening volume (1/4-1/2 on knob). Now there almost always is voltage drop when at a comfortable volume (knob maxed out). Further more, if P=V^2/R is any indication of wattage then this amp puts out around 1900 watts with a clean signal output. I'm not sure how that wattage compares to the wattage it put out when the bass was louder however it may be significantly lower than the stated 3000 due to manufacturers lying and a weaker alt (this amplifier could put out more with a better alt.). I don't think it's the amplifier dying?

I apologize for the long unorganized post. I've been working with this setup all day and have a massive headache. Thank you to everyone who took their time to read it.

 
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Jeffdachef

Gunz That Turn on Nunz
Feb 5, 2013
17,261
252
South Coast Metro, CA
get a male aux to male RCA y splitter and do a straight from phone test, if thats louder than its either the head unit output or the RCA is bad.  If it is weaker than before then its an amp/wiring/ground/sub/enclosure issue

 

BreadLord

Junior Member
Mar 28, 2018
17
0
Gaffney
get a male aux to male RCA y splitter and do a straight from phone test, if thats louder than its either the head unit output or the RCA is bad.  If it is weaker than before then its an amp/wiring/ground/sub/enclosure issue
I have an aux to rca cord from my old radio. I can do that test tomorrow. I may download a db meter on another phone, not to see how loud it is but for comparison between the radio and the straight aux. I'll update you tomorrow 

I would hope it isn't the radio as it is a week old. I get the same voltage on the front/rear/subwoofer preouts so at least it is consistent. I did test the RCAs for shorts and found none 

 

BreadLord

Junior Member
Mar 28, 2018
17
0
Gaffney
get a male aux to male RCA y splitter and do a straight from phone test, if thats louder than its either the head unit output or the RCA is bad.  If it is weaker than before then its an amp/wiring/ground/sub/enclosure issue
Wasn't sure if you wanted me to adjust my gain to compensate for the phone's lower voltage or not so I did both. On the straight phone test without touching the gains it was a lot quieter. After setting the gains with an oscilloscope it was the same as the radio

 

BreadLord

Junior Member
Mar 28, 2018
17
0
Gaffney
I mean is it possible that the amplifier has suddenly started outputting less? Although using the equation it is putting out a fair amount, it is nowhere near rated. I'm also considering a failing alternator but am unsure.

 

Jeffdachef

Gunz That Turn on Nunz
Feb 5, 2013
17,261
252
South Coast Metro, CA
I mean is it possible that the amplifier has suddenly started outputting less? Although using the equation it is putting out a fair amount, it is nowhere near rated. I'm also considering a failing alternator but am unsure.
its definitely amplifier/wiring/electrical related.  Need to do further troubleshooting like if you have a different amplifier.   It is a hifonics which is pretty much overpriced power acoustik so reliability and actual performance is next to nothing but again too early to say without troubleshooting.

Its not a failing alternator if it was, your amp would shut down and you'll have even more system dimming, voltage drops. The fact that you arent pulling as much current as before means your actual power output from the amp dropped somehow.   

Did you actually take out each sub and test each pair of voice coils to see the actual impedance rating?  You might have a bad coil somewhere.

Did you actually measure voltage drops of the car while playing? 

 

Boomin_tahoe

Hurtin' feelings errrday.
Jul 24, 2005
15,249
132
WA
Get a better HU. You'd be surprised at how much it'll increase the sound of your system. Consider it as the "heart" of your system. Stay away from those BS brands you mentioned.

 

BreadLord

Junior Member
Mar 28, 2018
17
0
Gaffney
Get a better HU. You'd be surprised at how much it'll increase the sound of your system. Consider it as the "heart" of your system. Stay away from those BS brands you mentioned.
You're completely right, it's terrible how only two brands make options for not cutting my dash. I was considering remotely mounting something but it's just not as convenient. However, I get the same output from all 3 of the different sources I've tried. I contacted who I purchased the amp from and they have agreed to replace it. I'm also taking my alt to be tested tomorrow. The Retrosound is way overpriced but it is not too terrible. I've looked at the waveform from the preouts and it does not clip. The voltage is pretty low but better than my last radio 

Anyway I'll be testing the alt tomorrow and the amp will be replaced. I'm fairly certain the amp replacement will fix the issue as everything else checks out. I will be rechecking my voice coils though as a previous poster asked about them.

 

Boomin_tahoe

Hurtin' feelings errrday.
Jul 24, 2005
15,249
132
WA
You're completely right, it's terrible how only two brands make options for not cutting my dash. I was considering remotely mounting something but it's just not as convenient. However, I get the same output from all 3 of the different sources I've tried. I contacted who I purchased the amp from and they have agreed to replace it. I'm also taking my alt to be tested tomorrow. The Retrosound is way overpriced but it is not too terrible. I've looked at the waveform from the preouts and it does not clip. The voltage is pretty low but better than my last radio 

Anyway I'll be testing the alt tomorrow and the amp will be replaced. I'm fairly certain the amp replacement will fix the issue as everything else checks out. I will be rechecking my voice coils though as a previous poster asked about them.
Prob a long shot but have you looked into http://www.metraonline.com and http://www.scosche.com for a dash kit for the '65 'stang? I would keep it original as that year it's value should you decide to sell it will go up as long as it's not modified, but maybe another place for the radio. 

 

BreadLord

Junior Member
Mar 28, 2018
17
0
Gaffney
Prob a long shot but have you looked into http://www.metraonline.com and http://www.scosche.com for a dash kit for the '65 'stang? I would keep it original as that year it's value should you decide to sell it will go up as long as it's not modified, but maybe another place for the radio. 
There really isn't a lot of aftermarket for this car. With the radio I went with, no modifying of the dash is needed so returning it back to original is easy. That's how all of my mods to this car have been. However, very few brands make a radio to fit the orginal dash so my options are limited 

 

Jeffdachef

Gunz That Turn on Nunz
Feb 5, 2013
17,261
252
South Coast Metro, CA
There really isn't a lot of aftermarket for this car. With the radio I went with, no modifying of the dash is needed so returning it back to original is easy. That's how all of my mods to this car have been. However, very few brands make a radio to fit the orginal dash so my options are limited 
ever thought about just saying fk it to the head unit completely, leave it completely stock and just have a DSP stored on the side hidden somewhere and play music through that instead? 

 

BreadLord

Junior Member
Mar 28, 2018
17
0
Gaffney
ever thought about just saying fk it to the head unit completely, leave it completely stock and just have a DSP stored on the side hidden somewhere and play music through that instead? 
Many people mount the radio in the glove box. I have thought about this but it is just not as convenient. In this case I believe the radio is fine though I think the issue has to do with the amp which the original seller said they would replace.

Is P=V^2/R (power in watts, voltage, resistance/impedance) an accurate equation for calculator amplifier output?

 

Jeffdachef

Gunz That Turn on Nunz
Feb 5, 2013
17,261
252
South Coast Metro, CA
Many people mount the radio in the glove box. I have thought about this but it is just not as convenient. In this case I believe the radio is fine though I think the issue has to do with the amp which the original seller said they would replace.

Is P=V^2/R (power in watts, voltage, resistance/impedance) an accurate equation for calculator amplifier output?
yup.  i'm not saying its the radio but i'm saying you have options if you actually want amazing sound which is with a digital sound processor, it doesnt even need to be in the glove box, it can be hidden under the seat, the unit is very small but 10000x more capable than any head unit on the market, you'll have absolutely amazing sound quality from all the tuning features.  80 bands of parmetric EQ, bandpass active capable crossovers, time alignment, phase control, etc...

 

BreadLord

Junior Member
Mar 28, 2018
17
0
Gaffney
yup.  i'm not saying its the radio but i'm saying you have options if you actually want amazing sound which is with a digital sound processor, it doesnt even need to be in the glove box, it can be hidden under the seat, the unit is very small but 10000x more capable than any head unit on the market, you'll have absolutely amazing sound quality from all the tuning features.  80 bands of parmetric EQ, bandpass active capable crossovers, time alignment, phase control, etc...
Oh man I didn't even realise you mentioned a DSP and yes I have thought about those and If I saw a deal on one I'd pick it up. The acoustics in this old car arent the greatest so some frequencies arent as loud as others. The quality of the signal in the head unit isn't that bad but the tuning capabilities are lacking.

 

Jeffdachef

Gunz That Turn on Nunz
Feb 5, 2013
17,261
252
South Coast Metro, CA
Oh man I didn't even realise you mentioned a DSP and yes I have thought about those and If I saw a deal on one I'd pick it up. The acoustics in this old car arent the greatest so some frequencies arent as loud as others. The quality of the signal in the head unit isn't that bad but the tuning capabilities are lacking.
yeah dayton dsp is 150 and 30 for a bluetooth dongle which you can control the tuning via smartphone and play music through it losslessly as well with aptx. 

 

Jeffdachef

Gunz That Turn on Nunz
Feb 5, 2013
17,261
252
South Coast Metro, CA
coulda skipped the whole head unit ordeal completely and had a much cleaner signal with better audio capabilities.  

Sorry off on a tangent than your original post haha.

 

BreadLord

Junior Member
Mar 28, 2018
17
0
Gaffney
yeah dayton dsp is 150 and 30 for a bluetooth dongle which you can control the tuning via smartphone and play music through it losslessly as well with aptx. 
Bluetooth tuning sounds very convenient. Guess that's on the wish list now lol. 

And I guess the only reason now for having bought this new overpriced radio is that the old custom audio sound was the ugliest thing ever. This retrosound looks more like the original. 

An update on the on the issue, I shipped the amplifier off because the seller agreed to replace. In 2-3 weeks when I get it back I'll for sure update and post If the issue is gone for future reference. As another note I had the alternator tested although I do not believe the results and will be going to a specialized alternator shop soon to have a test again because the auto parts store didn't know how to test it at first and said it failed but the alternator still makes current.

 
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Jeffdachef

Gunz That Turn on Nunz
Feb 5, 2013
17,261
252
South Coast Metro, CA
Bluetooth tuning sounds very convenient. Guess that's on the wish list now lol. 

And I guess the only reason now for having bought this new overpriced radio is that the old custom audio sound was the ugliest thing ever. This retrosound looks more like the original. 

An update on the on the issue, I shipped the amplifier off because the seller agreed to replace. In 2-3 weeks when I get it back I'll for sure update and post If the issue is gone for future reference. As another note I had the alternator tested although I do not believe the results and will be going to a specialized alternator shop soon to have a test again because the auto parts store didn't know how to test it at first and said it failed but the alternator still makes current.
whats your voltages with the car on?