[nightfire]

Hey guys. I'm planning to build a subwoofer to add some extension and a little fun slam to my K1000s.

It will be within a foot or two of my listening position (ear level) so it doesn't have to be powerful at all (I imagine 10 watts is more than sufficient).

I'm hoping it'll deliver, with tweaking, a linear response from 20hz - 50hz and roll off around 6dB/octave at that point. Does this sound reasonable?

I'd like to use a small driver - maybe 6". Any recommendations? Cost is no issue.. I'm looking for as accurate bass reproduction as I can achieve.

Is there any value at all to building a class A/AB amp for this? Or should I just go with a Tripath chip?

Am I likely to need to do some kind of phase correction? If so would a variable capacitor do this, or is there some other way?

Thanks.

 

[diff_lock2]

Run a cheap 15"...

It will be hard to control though... but will get to those low notes "easier".

 

[nightfire]

Quote:

Originally Posted by diff_lock2 /img/forum/go_quote.gif Run a cheap 15"... It will be hard to control though... but will get to those low notes "easier".

Are you crazy?

I'm not looking to rattle the windows, I'm looking for absolutely accurate, low-distortion sub bass reproduction. I listen at maybe 90dB at the loudest.

 

[randytsuch]

Hi Gord
To get down to 20 hz you need to move air, I doubt 10 watts into a 6 inch driver will get you there. For instance, look at Adire's subwoofers, they start at 10 inch, and then go to 12 and 15 inch sizes. I know why you want a 6 inch driver, but it wont get you there.

There are lots of kits out there for subs, these guys carry some
http://www.creativesound.ca/
using the adire drivers.

Some articles here
http://speakerbuilding.com/diy/
Another sub site
http://www.diysubwoofers.org/

I would get a hefty class d amp to drive it with. Even at 1 foot away, you need some power to move the cone, and get down to 20 hz.

At one point a while ago, I was considering making a sub for my HT, but it has not happened so far.

Randy

 

[Zenja]

Yeah, I imagine it would be really hard to get a driver to produce 20-50Hz flat at a reasonable level without using a big driver. It's just the way it works. It's not so you can break windows.

 

[Uncle Erik]

Nightfire- take a look at this:

http://www.audioxpress.com/bksprods/products/kw-6.htm

It's a servo kit for ordinary subs. If I remember correctly, it uses a second voice coil as an accelerometer to readjust the sub. It's been covered in a few AudioXpress articles, and it sounds like it would be a perfect companion to any electrostat, ribbon or K-1000!

I'm on the fence with ordering one. I am convinced of its worth, but I'm happy with the bass I have right now and don't really have the time to take on another project. Then again, I could always put one away for "when I have time."

But I think this is what you want. It'll turn mid-fi subs into something special.

 

[randytsuch]

Quote:

Originally Posted by Uncle Erik /img/forum/go_quote.gif Nightfire- take a look at this: http://www.audioxpress.com/bksprods/products/kw-6.htm It's a servo kit for ordinary subs. If I remember correctly, it uses a second voice coil as an accelerometer to readjust the sub. It's been covered in a few AudioXpress articles, and it sounds like it would be a perfect companion to any electrostat, ribbon or K-1000! I'm on the fence with ordering one. I am convinced of its worth, but I'm happy with the bass I have right now and don't really have the time to take on another project. Then again, I could always put one away for "when I have time." But I think this is what you want. It'll turn mid-fi subs into something special.

Hi
You don't happen to have the article, do you?
I am interested in reading more about this, curious how it works. Maybe I will buy the CD of back articles.

I have decided to upgrade my current HT sub. It is an old Energy sub. I was buying some parts at Apex Jr today (local to me), and on a whim, I bought a plate amp.

Randy

 

[nightfire]

Quote:

Originally Posted by Uncle Erik /img/forum/go_quote.gif Nightfire- take a look at this: http://www.audioxpress.com/bksprods/products/kw-6.htm It's a servo kit for ordinary subs. If I remember correctly, it uses a second voice coil as an accelerometer to readjust the sub. It's been covered in a few AudioXpress articles, and it sounds like it would be a perfect companion to any electrostat, ribbon or K-1000! I'm on the fence with ordering one. I am convinced of its worth, but I'm happy with the bass I have right now and don't really have the time to take on another project. Then again, I could always put one away for "when I have time." But I think this is what you want. It'll turn mid-fi subs into something special.

Hmm.. very interesting. I'd heard of the concept before but never seen any gear.

I'll look into it. Thanks.

 

[randytsuch]

I would also consider these kits
http://www.rythmikaudio.com/servo_product.htm

Some people at diyaudio have built them, and had good things to say about the sound quality of these subs.

Randy

 

[Chops]

Instead of using a subwoofer, why not just use a couple of Bass Shakers and a small T-amp under your seat?

It would/could achieve the same if not better results once tuned properly, and would be nearly 100% silent to others in the room.

 

[Paragon]

I would do something like three 8" in one box.

http://vandersteen.com/pages/2W_pict.htm My bro has one of those with a set of 2ce fronts. Nice system. I'm all for smaller, faster subs than a rattlebox.
I would think portless box would be best.

Now how to have the sub and k1000 going at the same time.. that may be tricky. Would you send the 20-50hz to the k1000 also? I probably would.

An easy test to see how it might sound, get a set of computer speakers (I have Klipsch) and disconnect the sats and just let the sub play while headphones are hooked up.

I did this with my Klipsch set and it does give some more depth to the low end (don't know if good or bad tho).. I think this sub is spec'd 29 to 120 or something like that from the two 6" drivers. It is ported tho. Grado SR325

 

[nightfire]

Quote:

Originally Posted by Paragon /img/forum/go_quote.gif I would do something like three 8" in one box. http://vandersteen.com/pages/2W_pict.htm My bro has one of those with a set of 2ce fronts. Nice system. I'm all for smaller, faster subs than a rattlebox. I would think portless box would be best.

Yeah, I was thinking that too. Though I'd rather the speakers aimed at my ears. I want to hear the 25-50hz band as well as feel it.

I play drums so I know what a bass drum sounds like... the K1000 on its own leaves much to be desired because the tufty bottom octave is missing.

Quote:

Now how to have the sub and k1000 going at the same time.. that may be tricky. Would you send the 20-50hz to the k1000 also? I probably would.

I was planning to leave my setup as it is (passing the full signal) and then use my DA10's headphone out, through a low pass filter, to drive the subs.

Matching the crossover point will be tricky. And I wonder if the phase difference would be noticeable.

Quote:

An easy test to see how it might sound, get a set of computer speakers (I have Klipsch) and disconnect the sats and just let the sub play while headphones are hooked up. I did this with my Klipsch set and it does give some more depth to the low end (don't know if good or bad tho).. I think this sub is spec'd 29 to 120 or something like that from the two 6" drivers. It is ported tho. Grado SR325

Oh I had a Velodyne 10" that was no slouch.

But I found it was still too sloppy for the K1000. It did sound powerful .. slamming .. though.

I'm actually thinking an open-back cabinet might be the way, with no worry about resonance. Price is no object here so if I have to use 4 6" drivers that's no big deal.

 

[dcheming]

Has anybody here had any experience with LAT?

http://www.tymphany.com/products_Tymphany_LAT.html

I haven't heard or even seen these transducers in person yet, but I'd sure like to. I would love to get my hands on a pair of these for experimenting.

 

[Paragon]

Aiming at you shouldn't do anything since sound that low has no perceived direction. You should be more worried about the acoustics of the room so you don't end up inside an area where the peaks stack. Most anything will probably be sloppy compared to a good set of headphones.

One design I always thought was good was something like
http://vandersteen.com/pages/five_sub.jpg
from their Model5 speakers http://vandersteen.com/pages/Model5alit1.html

That might be something to do with some of the small subs. Should be nice with a good set of 8 or 10s. Just a matter of finding an enclosure that will work.

You may need more than 10W also if you want clean and fast hits depending on the drivers.

Take a look at http://www.decware.com/newsite/mainmenu.htm
The horn loaded designs are neat. There used to be a page about his concrete horn in the basement that could get unbelievable low response..(below 10 I think) but aparently it started to crack the basement..

Anyhoo.. have fun.

 

[Chops]

So I guess my suggestion isn't even worth the time of day...