300-800W 8Ohm Sub Amplifier

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KostasTheGreat

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Joined 2003
Hello to all,
greetings from Athens!

i am constructing a subwoofer ... i have bought a dual coil 8Ohm 1200W Sub 12"
and i am looking for an amplifier for this bomb ;-)


can you propose me any project or any schematic?

something between 400-800W would be optimal or not?


thanks for your help!!

Im glad im here!
 
kASD

kASD

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Joined 2004
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CHECK THIS OUT!
 

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K

KostasTheGreat

Member
Joined 2003
Great Amp..
but what about the dual voice coil of that Subwoofer??

i have read this on the web:

Dual Voice Coil Subwoofers

Dual voice coil subwoofers are becoming a popular choice among car audio enthusiasts who want more flexibility in wiring their sound systems. While typical subwoofers have a single voice coil, dual voice coil (DVC) subwoofers use two separate voice coils, each with its own connections, mounted on one cylinder, connected to a common cone.

The key difference between single and dual voice coil subwoofers is the multiple wiring options DVC subs offer:
Parallel: A dual 4-ohm voice coil subwoofer with its coils wired in parallel presents a 2-ohm load to your amplifier. Since an amplifier produces more wattage at a lower impedance, the parallel connection ensures you'll get the most output from your amp. In the same fashion, if you have a stereo amplifier and two DVC subs, wire both subs for 2-ohm impedance (one per channel) for maximum output.


Series: Series wiring lets you configure multiple woofers to one amplifier at an acceptable impedance. Wire both coils in series for an 8-ohm impedance, and then wire two 8-ohm subs together in parallel for 4-ohm total impedance (perfect for most 2-channel amps bridged to mono operation). Another example: if you have a high-powered 2-channel amplifier, wire four 8-ohm subs per channel (each channel sees a 2-ohm load).


Independent: You can wire each voice coil to a separate channel of your amplifier, if you prefer not to bridge your amp. Independent wiring is a nice option if you're wiring two DVC subs to a 4-channel amplifier — one voice coil per channel.

DVCs and high-performance amplifiers
Some amplifiers are designed with an unregulated power supply — these amps are favored by mobile audio competitors for their superior performance. An unregulated amp's power increases dramatically when it sees a lower impedance load. For example, an amplifier that produces 75 watts RMS x 2 channels at 4 ohms would double its power to 150 watts x 2 with a 2-ohm load. DVC subwoofers (particularly the dual 2-ohm models) give you the flexibility to wring every bit of power out of this type of amplifier.

Also, if you choose to add an unregulated amp as a power upgrade to your existing DVC subwoofer system, you can simply rewire your subs for optimum impedance. Remember that most car amps are stable down to 2 ohms in normal operation, and to 4 ohms in bridged mode. It's important to check your amp's manual for its operating parameters before hooking up a DVC sub wired for low impedance!

A DVC sub offers the same performance whether it's wired in series or parallel. Its power handling levels, frequency response, and other specifications do not change — the only difference is the impedance presented to the amplifier. As a result, you'll use the enclosure that's recommended for your sub, no matter how it's wired.
Click to expand...

one of this amp in each coil ??
 
Easyamp

Easyamp

Member
Joined 2003
easyamp.com
I agree with skinnyboy, sub's with lot's of flare usually have more attention paid to how they look then how they sound. Also power ratings are useless unless a duration of the power rating is included, sustained, 100ms, 10ms, etc.

You might be better off starting with something a bit more respected like some peerless xls's or at least some good dayton woofer's.

As for design flexibility, if your not a mass market installer (best buy, circiut city, blah blah) you should build your system to fit your needs.

And don't forget, that to make your system sound twice as loud you must have an increase of a factor 10. (+10 dB)

If you double the power (+3 dB), you will only be able to detect a slight increase in volume. 2,4,8,16,32,64,128,256,512watts etc and for each step you will notice a slight increase in volume but 10watts to 100watts would effectively double the output power of 10 watts.

So shoot for a more efficient system and not a power hungry animal.
 
K

KostasTheGreat

Member
Joined 2003
2,5" 4 -Layer KSV
Freq.: 20Hz - 1,5 kHz
Spl: 98 dB
120 oz Magnet
Vas: 44 Liter
Xmax: 1"
Tiefe ca 22 cm

i have found those specifications for the sub.. good or not ? ;-)

better to go for a 300W 8ohm amp
or 800-1000W 2Ohm amp?

i just need a super powerfull sub for my home theatre..
i have already build a Gainclone amp.
 
Circlotron

Circlotron

Member
Joined 2002
pjacobi said:
> Freq.: 20Hz -
> Spl: 98 dB
> Vas: 44 Liter
Click to expand...
Low Vas = rock hard suspension = high resonant frequency.
To then bring it back down to 20Hz the cone has to be made HEAVY. In turn, that makes the efficiency go right down the toilet.
To bring the efficiency back to a sensible figure, and especially to get it as high as 98dB you are going to need a magnet so strong it is going to have an event horizon around it! :bigeyes:
 
Circlotron

Circlotron

Member
Joined 2002
Well, it might be a sort-of alright sub, so maybe you could measure the actual Thiele/Small parameters as opposed to the published ones and then decide on a box from there. It probably won't be all bad - it's suprising what you can do with a speaker that is below the dignity of many other people.

From the picture it looks rugged enough at least. C'mon! Lets make something useful out of it! First you gotta measure those parameters. Plenty of info out there on how to do it. I posted a spreadsheet here http://www.diyaudio.com/forums/showthread.php?postid=300333#post300333 that helps. It uses the "1k resistor in series and measure the voltage peak across the speaker method". Use the version in post #16, the earlier ones are not as good. Also some useful info in post #1.
 
T

thoriated

Member
Joined 2003
Hi, Kostas -

The best thing about your driver is probably the linear Xmax. That's the case, along with the low Fs for the 16 similar drivers I plan to use in my HT subwoofers (8 per channel). The actual efficiency in db/w/m is probably significantly lower than the number you quote and the continuous power handling is probably less than the figure you mention. I nearly fried the dual VC of one of my '1000 watt' woofers of this type with less than a minute of around 500Wrms (no smoke, but a strong odor of VC components starting to volatilize), and think that the 150 WRms each I plan to give them when used as subwoofers is more realistically within their capabilities.
 
K

KostasTheGreat

Member
Joined 2003
Hello guys,
please forgive me but i will be a little late for posting some results from the whole project because all the february is the examinations period in my university ;-)
so now its time for studying electronics ;-p then ill be back to apply my knowledge ;-p

ill keep you informed for the progress of this project
thank you
 
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