hi ...
i've completed a subwoofer system with 12in subwoofer for my car use. Initial testing indoor using a normal quality car amplifier (used for my PC system) the bass is tight and well controlled.
Problems rise when it is used together with my car amplifier which has bass boost at 45Hz and i set it at a mild boost of 4dB. The amplifier setting of the crossover is at 85Hz. The sound of the bass hits very low frequency but it is not tight when playing techno or dance tracks with very fast beats ...
The amplifier is connected to a parametric preamp which has subwoofer controller.
I here also attached the graph of the predicted frequency response by WINISD, photo of the completed subwoofer, amp photo and specification.
I wonder if my box is not properly designed or my car amp have damping factor issues.
thanks for advices and solutions to my problem
i've completed a subwoofer system with 12in subwoofer for my car use. Initial testing indoor using a normal quality car amplifier (used for my PC system) the bass is tight and well controlled.
Problems rise when it is used together with my car amplifier which has bass boost at 45Hz and i set it at a mild boost of 4dB. The amplifier setting of the crossover is at 85Hz. The sound of the bass hits very low frequency but it is not tight when playing techno or dance tracks with very fast beats ...
The amplifier is connected to a parametric preamp which has subwoofer controller.
I here also attached the graph of the predicted frequency response by WINISD, photo of the completed subwoofer, amp photo and specification.
I wonder if my box is not properly designed or my car amp have damping factor issues.
thanks for advices and solutions to my problem
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Last edited:
Hi,
Tune your box a lot lower or go sealed for in car use. The mud is probably
the inevitable bass overload you will get below the port tuning frequency.
Tune it down to between 33Hz and 38Hz.
55L is a big box for sealed giving a low Q of 0.47. Tuning the box to 26Hz,
an octave below the current tuning, will be better than sealed IMO here.
rgds, sreten.
Tune your box a lot lower or go sealed for in car use. The mud is probably
the inevitable bass overload you will get below the port tuning frequency.
Tune it down to between 33Hz and 38Hz.
55L is a big box for sealed giving a low Q of 0.47. Tuning the box to 26Hz,
an octave below the current tuning, will be better than sealed IMO here.
rgds, sreten.
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Last edited:
Ok lower the tuning frequency. But i tried the subwoofer system before using another car amp which is used for my computer subwoofer (DIY sub also) and the bass there is tight. The amp signal feeds from a custom made bass boost circuit peaking high pass filter.
The previous version of my car subwoofer (i sold off already) also have the same issue when using the car amp the bass sound sluggish and using another amp it sounded tight and nice ...
Hi,
A computer sub amp may have a bass roll-off to suit a boom-box bass
alignment, but it won't go deep, it probably doesn't even try to do that.
It depends also on whether the bass boost is just a 2nd order peaking EQ,
or a 2nd order peaking high pass filter what low bass distortion you will get.
rgds, sreten.
A computer sub amp may have a bass roll-off to suit a boom-box bass
alignment, but it won't go deep, it probably doesn't even try to do that.
It depends also on whether the bass boost is just a 2nd order peaking EQ,
or a 2nd order peaking high pass filter what low bass distortion you will get.
rgds, sreten.
Ok lower the tuning frequency. But i tried the subwoofer system before using another car amp which is used for my computer subwoofer (DIY sub also) and the bass there is tight. The amp signal feeds from a custom made bass boost circuit peaking high pass filter.
The previous version of my car subwoofer (i sold off already) also have the same issue when using the car amp the bass sound sluggish and using another amp it sounded tight and nice ...
Forget to mention ... the amp for the computer system which i used to test my New subwoofer is actually a Diy 4 channel 25W LM1875 based amp. 2 channel were bridged to test the subwoofer. And the bass boost module is also a DIY system build to suit my subwoofer system. The boost is around 4db @ 45Hz using peaking high pass 2nd order Peaking filter. Low pass was crossed at 85hz cutoff. I even tested it with another spare car amp i have it sounded tight and nice.
1. Fb is too high. 50 Hz? That's way too high. Try 30 Hz
2. Remove the bass boost @45 Hz.
3. Try orienting the box a bit differently in your car.
4. What LP filter are you using on the subwoofer? 80 Hz? Try a higher frequency. The rear seat in a sedan can act like a natural LP filter. Now add to that the LP filter on your subwoofer amp and possibly the LP filter on your deck or EQ and the effect of the driver's Le, and the end result may be that the subwoofer is simply being effectively filtered at too low a frequency for car audio use.
For some background, I use 2x12 (sealed) subs in my car. The LP filter on my deck is set to 125Hz, 12dB/octave, and on the amp 200Hz/24dB/octave. And I drive an SUV, so no "rear-seat LP filter" to worry about. Le for the subs works out at 1.5mH at a 2 ohm load.
2. Remove the bass boost @45 Hz.
3. Try orienting the box a bit differently in your car.
4. What LP filter are you using on the subwoofer? 80 Hz? Try a higher frequency. The rear seat in a sedan can act like a natural LP filter. Now add to that the LP filter on your subwoofer amp and possibly the LP filter on your deck or EQ and the effect of the driver's Le, and the end result may be that the subwoofer is simply being effectively filtered at too low a frequency for car audio use.
For some background, I use 2x12 (sealed) subs in my car. The LP filter on my deck is set to 125Hz, 12dB/octave, and on the amp 200Hz/24dB/octave. And I drive an SUV, so no "rear-seat LP filter" to worry about. Le for the subs works out at 1.5mH at a 2 ohm load.
I completely agree with Brian. If you need "bass boost:", then you just don't have enough subwoofer or amp, period. Tune that box right (low 30s), bump up the LPF to 100 or 110. Or just get a different amp. Remember, we just can't hear what you're hearing and can only go by your description, which can mean different things to us.
It partially sounds like you've made up your mind about the amp. So just replace it. Gotta pay to play in this game. Otherwise you're left with modifying your system in the other ways that have been described.
It partially sounds like you've made up your mind about the amp. So just replace it. Gotta pay to play in this game. Otherwise you're left with modifying your system in the other ways that have been described.
replacing my amp i think is out of my option i think cos this amp is quite powerful as it havent bridged to the subwoofer. now it just run on 1 channel only for the subwoofer. Maybe one day i would consider modify the crossover and the bass boost of the preamp section of the amp and see if it helps...
Mobile Audio=Always Tweaking.
That looks like a pretty large box, even ported, for a 12" driver, but I have not looked at Alphasonic in a long time.
In-car, you get a 12db (average) boost at the outset, and don't forget the completely different acoustic environment.
Your best bet is to build your enclosure to match your car and speaker requirements, making sure you have your TS parameters correct, I am wondering about a couple of them: Fs @ 30+ Hz for a 12"? and your Sd should be over 110 sq" for any "normal" 12" driver, although as with all things, change is expected.
2 cubic feet is not too bad for mobile audio subs, pretty typical in fact, but as with the others already chimed in, tune it lower. Also, double check your source materials and filters. You may have your computer filtering out subaucoustics/sonics (generally recognized as >20Hz, sometimes as high as 60...) automatically, whereas your car amp lets you tailor your music to your own terms.
My car system: Kenwood CD-deck (3+ years old) front xover @ 150, rear at 120, sub @ 100; who knows what slope///
Front channel running off the (cough hack spit) 50 wpc deck, rear from 50 (honest) wpc RMS with xover @ 200 12db/octave, subs @ 120/12 db/octave. 4 Ohm bridged, 400WPC max amp. Sealed box to OEM specs for size, my dimensions for fit.
Cut in the boost for the old school and when I wanted to be obnoxious, otherwise left flat.
My amp channels: a Crunch 150 I have kept with me for 10+ years pushing subs mostly, rears this round; and a Crossfire V402 for the subs: a pair of 8" Infinity.
Played with a 500 watt monoblock, guess I'm getting too old, but it overpowered the rest of the system even at low settings. I have it for sale if your interested....
MLK
That looks like a pretty large box, even ported, for a 12" driver, but I have not looked at Alphasonic in a long time.
In-car, you get a 12db (average) boost at the outset, and don't forget the completely different acoustic environment.
Your best bet is to build your enclosure to match your car and speaker requirements, making sure you have your TS parameters correct, I am wondering about a couple of them: Fs @ 30+ Hz for a 12"? and your Sd should be over 110 sq" for any "normal" 12" driver, although as with all things, change is expected.
2 cubic feet is not too bad for mobile audio subs, pretty typical in fact, but as with the others already chimed in, tune it lower. Also, double check your source materials and filters. You may have your computer filtering out subaucoustics/sonics (generally recognized as >20Hz, sometimes as high as 60...) automatically, whereas your car amp lets you tailor your music to your own terms.
My car system: Kenwood CD-deck (3+ years old) front xover @ 150, rear at 120, sub @ 100; who knows what slope///
Front channel running off the (cough hack spit) 50 wpc deck, rear from 50 (honest) wpc RMS with xover @ 200 12db/octave, subs @ 120/12 db/octave. 4 Ohm bridged, 400WPC max amp. Sealed box to OEM specs for size, my dimensions for fit.
Cut in the boost for the old school and when I wanted to be obnoxious, otherwise left flat.
My amp channels: a Crunch 150 I have kept with me for 10+ years pushing subs mostly, rears this round; and a Crossfire V402 for the subs: a pair of 8" Infinity.
Played with a 500 watt monoblock, guess I'm getting too old, but it overpowered the rest of the system even at low settings. I have it for sale if your interested....
MLK
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