Beginner wanting to build a subwoofer amp

[mk2singh]

Hi all

I am a beginner so please bare with me as I'll probably have a lot of silly questions

I have a car subwoofer which I want to use to make a home made subwoofer. Now I have been looking at amplifiers for it but can't seem to find the best solution. One idea was to use a car amplifier and power it from a computer PSU but then I would have too much equipment everywhere and I'd like to have the smallest foot print as possible.

I had a look through the store and with some help from the help desk on there I was suggested to take a look at the honey badger amp. Seems like a good DIY build and I'm hoping I can just use one of the boards to use a mono amp.

Would you suggest this is the best route for me for m requirements?

Also I had a look through the build guide for the honey badger and I couldn't see anything about the power supply side of things. I'm not very electronic minded but I like to build and do things my self and plus its a learning curve for me. Is there a simple guide out there to build a power supply for this amp with step by step instructions?

Hope someone can help


Thank you

[Saturnus]

Originally Posted by mk2singh

I have a car subwoofer which I want to use to make a home made subwoofer.

Car components belong in the car not in the home. It's highly doubtful you can get anything useful out of it.

What you're looking for is actually not an amplifier design. It a design for a good subwoofer instead.

[paskal9]

Originally Posted by Saturnus

Car components belong in the car not in the home. It's highly doubtful you can get anything useful out of it.

What you're looking for is actually not an amplifier design. It a design for a good subwoofer instead.

i disagree.
while most sub drivers made for the auto world are not suitable for home theater, some models are suitable and perfect for home use.

most car sub have high resonant frequency which render them useless for any low end frequency playback which are deemed important for home use. car sub are not expected to do any high output below <35Hz but home sub should extend to below 25Hz to have the proper cinematic feel.
high Fs car sub require a large enclosure to get adequate low frequency output.

you need to do driver simulation to know how they'll behave and get the enclosure design.
good place to start at
DIY Subwoofers at Home Theater Forum and Systems - HomeTheaterShack.com
and
DIY Speakers and Subs

if you're not particularly knowledgable with diy electronics i think you're better off using a commercial pro amp to power the sub.

[mk2singh]

its not for a home theatre system. its for my music player hifi which has a sub out.

Thanks for your input.
I have heard of lots of people using car subs for this use.

Can anyone else help me with this?

thank you

[paskal9]

Originally Posted by mk2singh

its not for a home theatre system. its for my music player hifi which has a sub out.

Thanks for your input.
I have heard of lots of people using car subs for this use.

Can anyone else help me with this?

thank you

are going to use back the driver that you already have or are you going to buy a new one?

again, if you have no previous experience with audio electronics it's best to avoid trying to DIY the electronics part of the equation, especially if it's class d.

[mikje]

One of the adventures inherent to DIY is making something work that others say isn't possible. However, along with that comes finding out that sometimes our efforts don't give us the results for which we were hoping. In other words, try to make this work, but beware that it might not be what you want.
So, with that said, here is a link to a thread along the lines of this one with some amp suggestions. Possibilities for inexpensive subwoofer amplifier kits?
This looks interesting and fun. I too have some subwoofer drivers which I would like to power without taking up a lot of room and without breaking the bank. I'll be interested to see how your build goes.
Have fun!
Mike

[mk2singh]

I see it as a learning curve. If it works then I will have made something that others said wasnt possible as you said Mikje. If it doesnt then ill hopefully learn why it didnt.

Im not looking to build something ground breaking. Just really want to have a go at doing something like this and having some fun along the way. Its same thing with learning a new skill. You have your own way off learning.

In one of my other threads I learnt how to repair my broken Alpine amplifier, with help from forum user Perry Babin. And yet I didnt know anything about amplifer repair when I started.


Thanks Mikje for giving me some guidance and links. Will definately look into them.

I take it the Honey Badger amp wont be suitable for my needs then?


Thank you

[mikje]

Originally Posted by mk2singh

I see it as a learning curve. If it works then I will have made something that others said wasnt possible as you said Mikje. If it doesnt then ill hopefully learn why it didnt.

Im not looking to build something ground breaking. Just really want to have a go at doing something like this and having some fun along the way. Its same thing with learning a new skill. You have your own way off learning.

In one of my other threads I learnt how to repair my broken Alpine amplifier, with help from forum user Perry Babin. And yet I didnt know anything about amplifer repair when I started.


Thanks Mikje for giving me some guidance and links. Will definately look into them.

I take it the Honey Badger amp wont be suitable for my needs then?


Thank you

I think that ideally, you'd want an amp like the Honey Badger to be bridgeable to be a good fit for a subwoofer amp. I don't know if it's bridgeable or not. I couldn't find anything that said it is.
However, if your sub is a dual voice coil sub, a stereo amp like the Honey Badger should work fine, especially for home music applications.
Mike

[paskal9]

quoting posts that i've made in some other thread. to prove that i'm not coming from some bull.

Originally Posted by paskal9

managed to make them stable enough that i've decided to case them up and use them as the resident sub amp.

the output inductor goes too hot after 2 hours of movie run with huge bass so i've added an 80mm fan blowing to the pcb. gonna find another fan and do a permanent installation. the output mosfets are mounted to a heatsink underneath the pcb. the blue pcb on the top right is a 2x4 balanced minidsp to provide all the necessary dsp processing to the amp.


they're quad channel irs900d bridged into 2 channel powering a 4 ohm sub. switching frequency are reduced to 250khz, output inductor are made from T106-2 iron toroid with 21uh inductance. output mosfet are irfb5615.

each of the bridged channel powers one of these 15" diy sub:


in room frequency response of the subs powered by the amp:

stopped at 102db before i could see any compression limit on the sub. don't wanna break the house.

it costs me about ~USD$200 to build a 4 channel class D, bridge them stably into 4 ohm and extract about 1kw from each channel and drive my dual sub cleanly until ~102db. it could go higher, but the window started making noise.




there's proper simulation and design done beforehand.

i've previously audited several high end, top of the line home theater subs from rythmik, svs, paradigm and i know how a good high end sub should sound like. i've spent about ~USD$1000 building both sub complete with the amp that's driving them. and while they might not have the outlook of the most expensive subs, they do sound like one.

there's a proper thread documenting the entire build process from start to finish at some other local forum. and while the idea of building your own sub seems a bit far fetched to most people, it's definitely doable. and it's definitely worth it (if you have no other hobby to fill your weekends with).