low quality base sound

[joelumuna]

gud day to all,

pls. any one help me to improve the base sound of my scooter stereo wired in motorcycle (honda wave r)

i built an amplifier for my motorcycle (honda wave r ) and connect to mp3 player. i use 3 amps. 1st amp is for left channel and 2nd amp is for right channel w/c audio frequency response is from 120hz-20khz and the 3rd amp is for sub woofer w/c frequency response is 40hz - 150hz. it works fine but i notice that the sub woofer is begin to distort (the bass sound) when i turned the volume control at midpoint.
is there something wrong to my sub woofer baffle design

my sub woofer baffle is triangle in shape to fit it to my scooter u-box.

 

[transistor495]

Hi,
Proper air-exhaust holes are there for sub-woofer cabin?

 

[Whats that smell?]

Ur port or baffel dosent need to b any particular shape but the box must be the correct size for that particular woofer sounds like it may have too larde a port, how big is this woofer?

 

[joelumuna]

all sub woofer need air vents to produce low frequency, i put air vent in u-box but the bass sound became flat and weaken. i want my sub woofer perform like in its original baffle (rolling bass).
is there any one help me to design (with measurement) a baffle for my sub woofer that produce a rolling bass sound

 

[joelumuna]

about 5 inches in diameter, 50 watts

 

[Whats that smell?]

It depends on your woofer parameters as far as excrusion.

 

[joelumuna]

i have no idea on the parameters of my sub woofer,can u give an example so i can gathered the data of my sub woofer parameter

 

[Whats that smell?]

Well excrusion is how far the speaker moves in either direction, by what ur saying it sound as if the box you have may be to large which will result in poor low frequency.

 

[audioguru]

Speakers have manufacturers spec's. The enclosure must have a volume that suits the spec's.
Some speakers work better with a vent and others work better in a sealed enclosure.

Either the amplifier is causing clipping distortion when you turn up the volume, or the little "sub-woofer" is having excursions of its cone and voice-coil that exceed its spec's and it is bottoming-out.

A 5" speaker is too small to be a sub-woofer to produce low frequencies at fairly high power.

 

[transistor495]

Man,
What is the powersupply you are using for sub-woofer amp? I think you are not feeding the required ampere for the sub-woofer amp. Is that from your motorcycle battery??

 

[joelumuna]

the mentioned woofer is tested and proved that it can produce low bass sound because all components including amps are previously enclose in one system (baffle included),

 

[audioguru]

The Philips TDA1562 amplifier IC operates in class-H. When it senses a high level input signal then it doubles the supply voltage which allows almost 4 times the output power than an ordinary bridged amplifier.
Its output power at clipping (low distortion) into 4 ohms with a 14.4V supply is 55 Watts RMS. Most of the time the voltage doubler is not used which keeps the IC cooler.

Ordinary car radio bridged amplifiers produce 15 Watts RMS into 4 ohms at clipping or 4 watts into 8 ohms.

 

[joelumuna]

the amps need a split power supply, +12,-12 and 0 ground reference with a current consumption of 1.5 amperes , so i design a recommended power supply, i use two 12v battery in series and the common is connected to ground

 

[joelumuna]

my frnd,

i think i need, is an exact amount of volume design for my woofer

 

[audioguru]

Car radios don't use two batteries, they use a bridged dual amplifier to do it.
Yours has 24V. Then the signal swing at the sub-woofer is about 20V p-p which is 7.07V RMS. The output power to a 4 ohm speaker is 12.5 Watts and the output power to an 8 ohm speaker is 7 Watts. Very low power.

What is the impedance of the sub-woofer?
What do you think is the continuous RMS output power at clipping of the amplifier?

 

[Whats that smell?]

exact is hard to say without the exact factory specs but you can figure as follows: the cone area X ecrusion both in and out X 2, as an internal volume for a ported enclosure and take half the cone area for the port size. Thats not exact but that will get u close and u can tune ur speaker by chaning the port length a little.

 

[joelumuna]

thnx for the idea. is there any one help me to design a correct baffle size for the woofer (5 inch)

thxs in advance

 

[audioguru]

The manufacturer of the 5" speaker has detailed spec's for you to design your own enclosure and they have a recommended enclosure.

I don't think the little speaker would have a response below about 90Hz. A real sub-woofer goes down to about 30Hz.

Is the enclosure sealed or vented? I don't think you want rain water in the vent.

 

[joelumuna]

my woofer amps use 2 IC TDA2030 bridged together to produce greater output . i look this IC info in ECG. ECG says that this IC TDA0230 use +14volt, -14volt and ground and having an output power of 14 watts at 4 ohm speaker load, so if this IC is wired in bridged config. (BTL) the output power is more great than 2 IC wired as left and right channel

 

[joelumuna]

originally the woofer is attached to vented box while my design is sealed type because sealed type box fits in my motorcycle u-box