Micro computer speaker and amplifier build/design

[Jed]

http://www.madisound.com/catalog/product_info.php?products_id=8305

Image not available

I picked up a couple of these to test out. Might work out nice in a little computer speaker I have planned or in an "ultimate" micro mini speaker 3 way as a mid. I also have the Aurasound NS2s to compare them to. Should be interesting to see how they perform since they are cheaper than its 2" brother, which didn't do all that great considering the copper in the motor.

[Hdale85]

Ultimate mini 3 way huh? Hmm sounds interesting

[Jed]

Ultimate mini 3 way huh? Hmm sounds interesting

Just put the word "ultimate" in front of any description and it gets everyone's attention. It's a little trick I picked up from my rhetoric class. :B

[impala454]

"Nice little computer speaker" got my attention

[Jed]

"Nice little computer speaker" got my attention

With any luck these will have decent distortion performance and I can pair it up with the Aura NT1 tweeters I have on hand. Width could be like 4" by 5.5" high. There is so much junk out there for micro computer speakers I thought I could step in and try something. I've been doing more and more youtube listening and it would be nice to have something decent for playback. Maybe use one of those Tamps too.

Jed

[Paul Ebert]

It does look nice for that sort of an application (or for a line array midrange). The cutout for flush mounting looks a bit difficult.

I wonder what the x-max is...

[Jed]

It does look nice for that sort of an application (or for a line array midrange). The cutout for flush mounting looks a bit difficult.

I wonder what the x-max is...

Considering the 2" fullrange is around 1.8mm, I'm sure this 3" driver has a bit more travel- just look at the surround. I'd probably just put some foam around the driver for diffraction control. A round frame is always nice though!

[Johnloudb]

My mom could really use a nice little computer speaker. So, I'll be following this. Are you building a sub for it? My mom could care less though.

[ahaik]

With any luck these will have decent distortion performance and I can pair it up with the Aura NT1 tweeters I have on hand. Width could be like 4" by 5.5" high. There is so much junk out there for micro computer speakers I thought I could step in and try something. I've been doing more and more youtube listening and it would be nice to have something decent for playback. Maybe use one of those Tamps too.

Jed

I would be very interested in a little 2 way computer speaker too :T
Could be a fun project with my son.

[Jed]

I'm getting them in tomorrow and I'll let you all know how they test out. For the micro computer speaker I'm going to use an Aura NT1 tweeter. $25 per side in drivers shouldn't be too bad.

[Jed]

My mom could really use a nice little computer speaker. So, I'll be following this. Are you building a sub for it? My mom could care less though.

It would be cool if we could find an amplifier module that could go in a subwoofer and also power the satellites. Any recommendations? One of those peerless 6.5" SLS subs might be good or of course the TB 5"ers.

Jed

[Hdale85]

PE has a few amps that have speaker outputs as well I believe....like a 125watt amp. I'll look in a few.

[Johnloudb]

The Peerless SLS sounds good. I'll see what I can find in plate amps.

Edit: This would be my budget choice. I will probably use a T-amp for the HF.
Maybe someone will have better ideas.

Dayton 70W into 4 ohm

[impala454]

This little sucker comes to mind:

https://www.htguide.com/forum/showpost.php?p=229129&postcount=5

[augerpro]

I can't say enough good things about the TB W6-1139. That little sub really impressed me. It can fit in a tiny box (neo motor is a big help here) and has 13mm of linear excursion! It's well behaved even when driven past xmax. For a high quality sub/sat system I think the 8" would be the obvious choice, but the 6.5" is perfect for moms.

I think that Peerless SLS is cool, if it has lower distortion than the TB I could see using them in compact 3 way maybe. But if you are only using one woofer for sub duties I think the excursion of the TB wins out. Just my .02


Image not available

[Operandi]

It would be cool if we could find an amplifier module that could go in a subwoofer and also power the satellites. Any recommendations? One of those peerless 6.5" SLS subs might be good or of course the TB 5"ers.

Jed

I believe this Keiga plate amp has what you are looking for.

[Jed]

Thanks Brandon and Operandi. Good info. Wish that amp was about half the price- but it looks like it'll do everything I'd need it to.

[Hdale85]

Get a dealer license probably a lot cheaper then.

[Gir]

The Tangband W8-740 does a great job for a 8" (sub)woofer, and can also easily fit in a small enclosure like the W6. I built Zaph's BAMTM for a friend with two of the W8's in each tower, and those little guys are really impressive! They were shaking the whole house with ~500 watts to all four of 'em!

Also, for amp duty, I really love the idea of the 2.1 plate amp, but I don't think 50W is enough power. Perhaps we could take small amp for the speakers and mount it inside the sub along with a plate amp? I'd really love to see a fully integrated system, including a crossover for the sub so that only a stereo input is needed.

[dlneubec]

Hi Jed,

I know this won't fit into a box, but it is a very nice little amp for the price, is reasonably small in size, very flexible in what you can do with it and on sale for $129 including shipping. I picked one up to power the main MTM panels in my Nao Mini's and it does a very fine job, IMHO.

Emotiva BPA-1

[Hdale85]

He was looking for something that had 2 channels for the mains and a channel for the sub. That has 2 channels at most total.

[peter_m]

The BPA-1 is sold out but they should have a replacement coming out soon. I was planing on using 1 unit for the satellites and then the second unit in bridged mode for the sub.

[Johnloudb]

Another option would be to use a Dayton plate amp to drive the sub. Then use a T-amp or Emotiva BPA-1 to drive the satellites and to drive the speaker level inputs of the sub amp. This would let you use T-amp or Emotiva BPA-1 volume controll for the system. Of course, you couldn't use the high pass filter in this configuration, just the sat's natural roll off.

[Hdale85]

Well you guys are talking about quite a bit of money in amps.

[Gir]

Are there any 2.1 plate amps that put out 100+W for the sub? I smell a 2.1 amp project

[Hdale85]

I would probably use some sort of chipamp....but I've had a lot of problems with noise in those. I do have a couple Ref RevC's from twisted pear...they would work pretty well although probably too much power for the mains. They do like 52 watts per channel.

[impala454]

"The Klipsch ProMedia 2.1 Killer"

[Jed]

I finally got the Peerless 3" drivers in today and had a chance to take some quick and dirty measurements. THD is less than .5% from 300hz on up and remains mostly .2-.3% with no substantial peaks or dips. I'd post the graph but I want to make a proper baffle and compare them to the TB W4s, Accuton C79s, or any other driver I have laying around. Wish I had some Dayton RS52s here to compare them to, but from the looks of my distortion measurements the little Peerless might be in the same league from 800hz on up.

Right now I can't help but think of pairing up my L16s with these little guys and the D26.

More testing to follow. They've got my attention.

Jed

[Johnloudb]

Jed, that sounds great. Be interesting to see how they turn out for what ever project.

Edit: I'm itching to design a little class A 10-15W amp using discrete components. It would have a sub woofer line-level output and I could also add a switchable, HP filter for satellites. This can be a very simple circuit with little or no feedback and still have distortion <0.1 % at full output. I need to finish up some electronics projects I'm working on first. But, I may start a thread on that as an option for your computer speaker. Just thoughts right now.

[mike93lx]

jed, after taking your measurements, ho do you feel that this would do in a single driver, full range setup? Madisound's site suggests an 80 cubic inch enclosure and I was contemplating trying that out for a pair of basic computer-type speakers.

Thanks!

[peter_m]

Are there any 2.1 plate amps that put out 100+W for the sub? I smell a 2.1 amp project

There is a 50w sub & 25+25w satellite plate amp at Madisound and Solen.ca. Don't know how the cross-over performs... is it just a low-pass for the sub, or does it have also a high pass for the satellites? Price was around 150$ Anyone tried it?

[Jed]

jed, after taking your measurements, ho do you feel that this would do in a single driver, full range setup? Madisound's site suggests an 80 cubic inch enclosure and I was contemplating trying that out for a pair of basic computer-type speakers.

Thanks!

It would work but a simple 2-way with an Aurasound would be better. This driver has some ringing above 10k and it will require a notch to suppress the cone breakup. It doesn't seem quite as extended as the W4-1337 above 10k. I plan on doing a harmonic distortion comparison between this little 3" driver and the W4-1337. I'll post more detail about that next week.

Jed

[Jed]

Jed, that sounds great. Be interesting to see how they turn out for what ever project.

Edit: I'm itching to design a little class A 10-15W amp using discrete components. It would have a sub woofer line-level output and I could also add a switchable, HP filter for satellites. This can be a very simple circuit with little or no feedback and still have distortion <0.1 % at full output. I need to finish up some electronics projects I'm working on first. But, I may start a thread on that as an option for your computer speaker. Just thoughts right now.

That would be really neat, John. I'm interested for sure. I've got some time off this next week for Xmas break so you can be sure you guys will be seeing something from me.

[JonP]

Right now I can't help but think of pairing up my L16s with these little guys and the D26.

Jed

Hmmmm.... for a more econo approach, maybe the DA174 (or 135?) for the bottom? (probably pair with the Aura Titanium 3/4", for more econo)

The idea of micro 3 ways tickles me for some reason.

[dlneubec]

Jed,

Maybe this would be of interest. Have you heard of the Reckhorn A-400 sub amp. They also sell the electronic crossover section out of it for only $45.00. They have them at CSS.
Reckhorn F-1 at CSS

Combine that with some other portable or small amp and you might have what you were looking for. These look like they might have some real possibilities. Here is a link to more info at Reckhorn:
Reckhorn F-1 data

[Johnloudb]

That would be really neat, John. I'm interested for sure. I've got some time off this next week for Xmas break so you can be sure you guys will be seeing something from me.

Sounds good. I am looking into possible designs already. I want to keep it simple so people won't too intimidated and not try it. But, it should also have good performance. I'll start a thread once I come up with a design.

[peter_m]

Jed,

Maybe this would be of interest. Have you heard of the Reckhorn A-400 sub amp. They also sell the electronic crossover section out of it for only $45.00. They have them at CSS.
Reckhorn F-1 at CSS

Combine that with some other portable or small amp and you might have what you were looking for. These look like they might have some real possibilities. Here is a link to more info at Reckhorn:
Reckhorn F-1 data

Sounds interesting and inexpensive... but read this: http://www.hometheatershack.com/foru...fications.html

[Jed]

Good find Peter.

[Johnloudb]

Jed, I had this idea for a voltage gain stage. Basically I stole the input stage of Dennis Collins phono preamp and made it differential. I did this so I could get enough voltage output at low distortion. It still needs an output stage. I'll start a thead for help on that. I plan on using this dual Op Amp:

national semi's LME49860 - 44V Dual High Performance, High Fidelity Audio Operational Amplifier

It can output 22mA and drive 600ohm loads.

This should be a really quiet and low distortion amp. I'm just curious if this is of interest to anyone? I don't know how soon I could build it. I have obligations to finish some other work first. I could model it in Spice and let some adventurous person build it first?

Edit: Note - the input diodes are connected wrong!!

Image not available

[peter_m]

This should be a really quiet and low distortion amp. I'm just curious if this is of interest to anyone? I don't know how soon I could build it. I have obligations to finish some other work first. I could model it in Spice and let some adventurous person buit it first?

I could be interested. How many watts do you think it can pump out? how much do you think it could cost to build?

[Johnloudb]

That would be great. I think the parts cost is $120 - $200 depending on output stage. Class A output stage would cost more due to power supply requirements. It can put out up to 25W rms into 8 ohms.

PM me if you're interested. I don't want to ruin Jed's thread.

[Jed]

I don't want to ruin Jed's thread.

John, this discussion is great, so don't feel like you can't post it in this thread. Seems a lot of people can benefit from a small inexpensive 2.1 amplifier setup. To be honest, for $200 I'd just buy the Keiga, but to each his own and the more options the better.

[peter_m]

Jon,

at that price I would also go with off the shelf amps... I'm sure your design would sound cleaner but at that price it doesn't motivate me. I am waiting on parts for a 2.1 active crossover. If anyone wants, I can post my results once I get things rolling. I plan to use 2 off the shelf amps with Zaph's B3S + a sub I have yet to decide on. Any room for sub suggestions in here?

If yes, then I am looking for something inexpensive and maybe with two LF drivers firing in opposite directions to minimize any cabinet vibrations... would be a nice advantage for someone living in an apartment. Was thinking 2 of these even if they are not subs: http://www.partsexpress.com/pe/showd...number=295-366 or two of these: http://www.partsexpress.com/pe/showd...number=295-545

Peter

[Johnloudb]

I probably over estimated the price, was just guessing. But, I forgot this is for a computer speaker. If you lose the JFET inputs it simplifies the power supply and amp design. How does $45 sound, for same power, also a differential design?

[Jed]

I probably over estimated the price, was just guessing. But, I forgot this is for a computer speaker. If you lose the JFET inputs it simplifies the power supply and amp design. How does $45 sound, for same power, also a differential design?

$45 for 3 channels would be great.