Bass Louder and softer sometimes... Bass subwoofer problem - Bass loss

[BassErex]

Hello! From above, sorry from too long entry, I wanted to present my problem well. And I'm asking for advice
.
I have weird problem of bass from subwoofer. I fight with this about 4 years On two cars: Mazda 323f Ba and Mazda 6.
Sometimes bass is much better and softer. and sometimes i can feel better presure, but car body shake is the same. Mostly my bass sound is SH*T (sorry).
I see voltage, and if bass is very very nice, no diference with voltage drops ( Reading from amp terminal)
Voltage drops are small, so, its cant be a problem
My system on today:
Mazda 6 2007r Wagon 2.0.
Hifonics BRX 12000 + Audio System XIon 15-1000 (Wired 2 ohm)
Rodek 2180A + STX pa 1000 coppy on rear seats (Sorry, its not good but should not make problems, on mazda 323f ba the music was from the doors and this same problem)
My Head Unit is now alpine cde 178bt
My power:
- Lithium YINLONG 2 Packs (80ah) in trunk
-Alternator 300a (14,5 - 15,4V)
Wires Power:
- 2x 50mm2 from alt to batt (Sorry i dont know how Ga or Awg, I;m from polen) All wires 100% copper
- Sub Amp Hifonics 2x 50mm from terminalls (about 0,70m lenght)
- Rodek 1x 16mm2
Grounds Wires:
-1x 50mm2 from alt to chasis, and from chasis to batt
-1x 50mm2 from engine to chasis, and from chasis to batt
- 2x 50mm2 from battery to nearest chasis point
- Hifonics Grounds 2x 50mm2 is from lithium batt terminall, per ground wire is about 1,5M lenght (its problem? too long?)
Problem is going on this two amps, amp from music i have too diference with bass, are louder can be.
I checked:
- Grounds, looks nice
- Connections fuse, power wires, Sub speaker wires. (no lose)
-Rca connections on HU and amp, very tightly.

About this 4 years i tested:
Much amps (Emphaser ea 2500, Vibe Mono 21k, kicx ad 1.400)
Subs (2x 15 excursion sxx 15v2, Pa subwoofer, clarion sw 3012)
3-4 of PCS rca (I now from sub have Pride diamond)

Kenwood x7200dab Hu, and pioneer 3500ui.
Speaker wires.
Sometimes bass loud and soft can back but not always if:
I REconnect amp power
Change Port subwoofer (to lower or higher tuning)
Bass can back if i a few times put subwoofer to trunk, roof, trunk roof, trunk roof, can sounds be better.
Bass like run away, if most offen i restart engine.
Today i checked all connections, In sub box terminal very nice
tightened. Speaker wires are good.
I have a osciloscope, no distortions from hu and amps but:

My weird looks:
Volume on hu max 35
to 10 sound bass going up, 10 to 15 stop to sub, but music going up WFT?
I tried to see voltage output from hu, and i have problem to Get nice output voltage,
Cliping at 4,4v, but i put Preamp source USB is FULL, and i have full no cliped voltage about 4 volts on 32-33V on radio with Bass boostloudness off and flat EQ.
On aux From my xiaomi on full preamp source on hu, i have on good music max 1,2v.
I Set my gains property clean, with full clean voltage output Hu, but with sound quality and hitting bass, no diferences...

Any questions? Too long grounds amps? Thanks.

Click to read more...

 

[BassErex]

I've been building loudspeakers for 40 years, and the way I read the spec sheet, you are about 50L (net) to small on the box for 2 of these 15" woofers. This might sound decent on some playback and not on others, not how it should sound on anything! Gross internal volume for two drivers should be 180L gross (150net) tuned to 60Hz (vb) which will yield a 50hz response (which would be almost 4 octaves down, so I'm not sure what they are telling you there). Given the Vb and the tuning frequency of 60Hz, 57Hz would be your 3db down point, not exactly low in my book but not atypical for a larger driver. You can't just tune a box to your liking, where you think or want it to play; it needs to relate to the specifications of the woofer, the box and the woofer work together. According to the specs you list for the SPL box (the smaller option in this case), you need 180 liters of gross volume (this is the volume before negating the woofer drivers and the port displacement), 75 liters of net volume, or Vb at 75L per chamber (150L net for two drivers), and the port they recommend is 30cm x 12.5cm or 375 square centimeters, for the rectangle port opening with a length of 27.5cm. I didn’t do the conversion from round to rectangle (375sq cm is equal to an 8.25" port, maybe?), but I am guessing the port you are using is completely wrong. The resonant frequency (the point where the woofer vibrates undesirably) for this woofer is 35hz. Unless you are using a subsonic filter crossed at 20Hz, you shouldn’t tune below 35hz. This box does not appear to be correct for two woofers (not even close). The box you have is half the size it needs to be. These woofers are never going to perform correctly in this enclosure. It is important to note, larger woofers do not necessarily and in most cases, do not play as low as 10’s or 12’s usually do, or at all for that matter. 15’s rarely play lower than 12’s, they just move more air (are louder). Try disconnecting one of the woofers, closing up that opening (temporarily) and see if the sound is more to your liking. I think you need to think about starting over on this box. I have BASS box pro and can run the specs if you need, for an extended bass box tuned to 35-40, but it looks like it will be on the order of 6-8 cubic feet given the parameters that I found ( https://www.carhifitwente.nl//Files.../Product/3m9ky7D682XXT075Y3ZXm6T8mQ9100pf.pdf), that’s a REAL big box! Thid subwoofer, with a Qts of .83 and an EPB >50 is meant for ported, not sealed enclsures. Stuffing the port will not change this. These woofers are meant to perform best in ported enclosures.

My box is about 200l netto and brutto above 270liters, box is not problem, I definitely have it here Signal Sound Degradation

What is your voltage drop? Ideally you want it less than .05v difference from what it is at the battery, and what it is at the amp, and anywhere else you test it.

My voltage drop is in arena of 0,08v, I checked more or less
but I won't tell Exactly on this moment

 

[BassErex]

As far as I know, a capacitor is redundant with this YinLong 80ah battery.
you all don't think so, that puncture on amp body is a problem?
Its goind to rca ground, according to theory,
'''if the rca mass touches something, this can negatively affect the sound'''
And in this case, unwanted current has contact with rca ground, so its cause Sound Degradation?
Everyone is talking about something different, although amp body must have 0,000v not 0,7v and not 11v
Amps is not defective, i dont why this phenomenon occurs in my car.
Will grounding amps body, be an effective solution or not?
Thanks.

 

[Doxquzme Premium Member]

My box is about 200l netto and brutto above 270liters, box is not problem, I definitely have it here Signal Sound Degradation

My voltage drop is in arena of 0,08v, I checked more or less
but I won't tell Exactly on this moment


View attachment 50687



View attachment 50685

My bad, I thought I read that your box was 100L. I would agree that if your running a YinLong 80ah battery, the capacitor is redundant. I personally like to ground everything back to the battery ground up front, and usually double the ground lead back. I have 15' runs of1/0 to the rear battery and 2/0 gauge back to the battery up front, everything is grounded off a distribution block in the rear. It's a more expensive way to ground stuff but it's cleaner and removes ground loop (power) issues

 

[spokey9]

I just popped a hole in the rear and grounded to the frame

 

[Doxquzme Premium Member]

I just popped a hole in the rear and grounded to the frame

Well, that's one way of doing it. Did you grind off any paint and use a large surface terminal ring? It's important that the return voltage runs (the ground) be as large as the current runs to the amp - discharged current need to be able to flow as easily as current in. It's also important that if you are running the ground right off the amp that the be as close to the amp as possible (preferably within 18"). The other reason I run everything back is that a lot of cars these days, especially unibody cars, use epoxy to "weld" various parts of the body togother, not all metal (espcially glued sheet metal) in a car is a good ground becuase of that.

 

[spokey9]

Well, that's one way of doing it. Did you grind off any paint and use a large surface terminal ring? It's important that the return voltage runs (the ground) be as large as the current runs to the amp - discharged current need to be able to flow as easily as current in. It's also important that if you are running the ground right off the amp that the be as close to the amp as possible (preferably within 18"). The other reason I run everything back is that a lot of cars these days, especially unibody cars, use epoxy to "weld" various parts of the body togother, not all metal (espcially glued sheet metal) in a car is a good ground becuase of that.

My ground is good...I didn't just slap a bolt through some rust

 

[Jimi77 5,000+ posts]

Well, that's one way of doing it. Did you grind off any paint and use a large surface terminal ring? It's important that the return voltage runs (the ground) be as large as the current runs to the amp - discharged current need to be able to flow as easily as current in. It's also important that if you are running the ground right off the amp that the be as close to the amp as possible (preferably within 18"). The other reason I run everything back is that a lot of cars these days, especially unibody cars, use epoxy to "weld" various parts of the body togother, not all metal (espcially glued sheet metal) in a car is a good ground becuase of that.

And the gluing makes for a more noisy environment. Luckily the industry has gone to UTP (unshielded twisted pair).

 

[Doxquzme Premium Member]

My ground is good...I didn't just slap a bolt through some rust

Ha, ya never know and I never assume!

 

[BassErex]

Update 2: Last time after disconnecting the equipment from battery and all instalation of the car, (welding exhaust). And instaled back all powers (all wires are tight, no slack) I've noticed a bit more of a drop voltage on amps and very small power of subs. Oh ok, my volt meter readed 13,8v, so i caught a multimeter and test voltage on amp, I noticed every few seconds voltage drops to 11volts! it is possible that the drops are lower, but reading of multimetter is not fast... Maybe that's been my problem all along. My subs is now wired to 0,5 ohm on amp. At higher wirring (2ohm) i not see this problem on amp terminalls..
On my battery voltage is strong, so problem is only on wires..

I suspect a problem of wires ground, but i dont know why...
This time I will try to do as short as posible wires ground to amp,
I give grounds parrael 2x 50mm2 to chasis and of this same point chasis to amps, but 70mm2 wires x2

 

[spokey9]

Update 2: Last time after disconnecting the equipment from battery and all instalation of the car, (welding exhaust). And instaled back all powers (all wires are tight, no slack) I've noticed a bit more of a drop voltage on amps and very small power of subs. Oh ok, my volt meter readed 13,8v, so i caught a multimeter and test voltage on amp, I noticed every few seconds voltage drops to 11volts! it is possible that the drops are lower, but reading of multimetter is not fast... Maybe that's been my problem all along. My subs is now wired to 0,5 ohm on amp. At higher wirring (2ohm) i not see this problem on amp terminalls..
On my battery voltage is strong, so problem is only on wires..

I suspect a problem of wires ground, but i dont know why...
This time I will try to do as short as posible wires ground to amp,
I give grounds parrael 2x 50mm2 to chasis and of this same point chasis to amps, but 70mm2 wires x2

Sounds like you don't have the electrical needed to run at .5 ohm...maybe something is wrong with your alt or cells

 

[BassErex]

Sounds like you don't have the electrical needed to run at .5 ohm...maybe something is wrong with your alt or cells

Battery current is perfect, so, all more wires and electrical have nothing to this issue. Apparently the wires are stoned. Maybe a longer ground wire is a BIG FAIL.
if that doesn't help, There is no other solution to this problem

 

[spokey9]

Battery current is perfect, so, all more wires and electrical have nothing to this issue. Apparently the wires are stoned. Maybe a longer ground wire is a BIG FAIL.
if that doesn't help, There is no other solution to this problem

Wire your subs to 2ohm...you said you don't see the voltage drop there...at least until figure out why your voltage is dropping at .5

 

[BassErex]

Wire your subs to 2ohm...you said you don't see the voltage drop there...at least until figure out why your voltage is dropping at .5

I think, its not a problem. On My previous amp subs wired on 2 ohm and 7,2kw, and problem of bad sound the same...
tommorow i test new grounds points and parael with car body and battery. Wire ground now is new and 2x shorter, but power wires more longer...
If this not help so... Problem is in car, Mazda 6 sh*t.