Wolf PC Speaker for HT

[sandyh]

A buddy wanted a few really small speaker for for his living room HT and after some looking I saw Wolf's PC speaker and thought it might be a good starting point. When buying the parts, he asked me if we needed the cap since his receiver had variable crossover points and he does have a sub. As this was a super budget deal, I thought we could try them without it. I built him some quick sealed boxes that are 4"x4"x4" internal volume and sent them home with him. He said they really didn't sound good, but its a new system for him altogether, so I grabbed them back and sent him home with some other conventional 2 way speakers I had laying around to see if they sound OK to him.

Anyway, I'm sitting here in the living room listening to them and they do sound OK to me, but also a really underwhelming. I know they don't cost much and so I should keep my expectations in check. Also, since I didn't use the cap and have the XO in the receiver set to 80Hz, I wanted to check and see if that would be the issue. All of the kits/plans I've built over the years were large speakers that ran full range, but since I didn't follow the design and use the capacitor, I wanted to check and see if they would likely sound better with the cap installed and run with a full signal.

The biggest issue I hear from time to time reminds me of a soup can kind of resonance sound. I wish I could describe it better, but that's all I can put in words.

Anyway, any help in troubleshooting would be appreciated. As I said, it is possible my expectations are not in line with what is reasonable to expect for speakers of this size/cost. I just really don't want to see this guy get frustrated and go with a well known mass market tiny speaker 'lifestyle' system if we can do something ourselves.

Thanks.

Sandy.

[Sibelius40]

A buddy wanted a few really small speaker for for his living room HT and after some looking I saw Wolf's PC speaker and thought it might be a good starting point. When buying the parts, he asked me if we needed the cap since his receiver had variable crossover points and he does have a sub. As this was a super budget deal, I thought we could try them without it. I built him some quick sealed boxes that are 4"x4"x4" internal volume and sent them home with him. He said they really didn't sound good, but its a new system for him altogether, so I grabbed them back and sent him home with some other conventional 2 way speakers I had laying around to see if they sound OK to him.

Anyway, I'm sitting here in the living room listening to them and they do sound OK to me, but also a really underwhelming. I know they don't cost much and so I should keep my expectations in check. Also, since I didn't use the cap and have the XO in the receiver set to 80Hz, I wanted to check and see if that would be the issue. All of the kits/plans I've built over the years were large speakers that ran full range, but since I didn't follow the design and use the capacitor, I wanted to check and see if they would likely sound better with the cap installed and run with a full signal.

The biggest issue I hear from time to time reminds me of a soup can kind of resonance sound. I wish I could describe it better, but that's all I can put in words.

Anyway, any help in troubleshooting would be appreciated. As I said, it is possible my expectations are not in line with what is reasonable to expect for speakers of this size/cost. I just really don't want to see this guy get frustrated and go with a well known mass market tiny speaker 'lifestyle' system if we can do something ourselves.

Thanks.

Sandy.

Just a few friendly suggestions. I'm not familiar with this particular design at all, but if it calls for a cap, I'd use one. Small drivers often need some taming to remove ringing, and Wolf's not one to use parts unnecessarily. If you have it, use the receiver's auto setup function to set the Xover, level and distance, EQ, etc.; if it doesn't have one, I'd set the Xover to the highest possible frequency your sub will go to. 80Hz is good for speakers with real woofers, but with a "PC speaker" it probably ought to be at 150-160 Hz.

[alphaiii]

Wolf will probably chime in...

But for now - the cap isn't a high pass filter... it's used for capacitive loading of the driver to extend it's bass response...

[Wolf]

Wolf will probably chime in...

But for now - the cap isn't a high pass filter... it's used for capacitive loading of the driver to extend it's bass response...

That's correct! It's a very misunderstood alignment as far as lowend goes, as I get asked this all the time. The cap is required.

The issue with sounding 'tunnelly', or 'soup-can ringing' is likely not a good enough stuffing density, and likely without a lining of any sort. OR- you did not relieve the rear of the driver's cutout to allow it to breathe enough (if you front mounted it), and it literally is IN a tunnel.

As long as the driver is the NS3-193-8, that's all I can offer as fixes. The 4 ohm driver is not as flat and will not sound optimal.

Later,
Wolf

[alphaiii]

That's correct! It's a very misunderstood alignment as far as lowend goes, as I get asked this all the time. The cap is required.

The issue with sounding 'tunnelly', or 'soup-can ringing' is likely not a good enough stuffing density, and likely without a lining of any sort. OR- you did not relieve the rear of the driver's cutout to allow it to breathe enough (if you front mounted it), and it literally is IN a tunnel.

As long as the driver is the NS3-193-8, that's all I can offer as fixes. The 4 ohm driver is not as flat and will not sound optimal.

Later,
Wolf

Wolf,

Been meaning to ask you... assuming these are placed near a real wall (rear or speaker within 2-3 inches or so)... about what listening distance would be acceptable before the lack of BSC becomes an issue?

And is the rated sensitivity of the driver (80dB 1w/m) about right for sensitivity of this sealed cap-assisted alignment?

[Wolf]

Wolf,

Been meaning to ask you... assuming these are placed near a real wall (rear or speaker within 2-3 inches or so)... about what listening distance would be acceptable before the lack of BSC becomes an issue?

I've had them as normal standmounts in my LR, and the fullness is not an issue, listening at ~8'. I guess I notice more of the treble off-axis rolloff on these than the lack of BSC. The PA alignemnt balances them out pretty well to me.

And is the rated sensitivity of the driver (80dB 1w/m) about right for sensitivity of this sealed cap-assisted alignment?

You can use any sensitivity driver for a PA alignment, it has to do with box Qtc; and Qms, Xmax of the driver in question.

Later,
Wolf

[alphaiii]

I've had them as normal standmounts in my LR, and the fullness is not an issue, listening at ~8'. I guess I notice more of the treble off-axis rolloff on these than the lack of BSC. The PA alignemnt balances them out pretty well to me.

Good to know.

You can use any sensitivity driver for a PA alignment, it has to do with box Qtc; and Qms, Xmax of the driver in question.

Later,
Wolf

Sorry, I think I misworded my question. I meant is the sensitivity of the speaker in box the same as the raw driver (80dB), or does the PA alignment lower it at all?

[Wolf]

Sorry, I think I misworded my question. I meant is the sensitivity of the speaker in box the same as the raw driver (80dB), or does the PA alignment lower it at all?

Since it utilizes a boost from the Qtc for the cap to flatten out the bass range, I would say there is marginal sensitivity loss. It's probably not even noteworthy.

Later,
Wolf

[sandyh]

OK, bad assumption on my part regarding the cap acting only as a high pass filter. I really never have figured out this hobby for sure.

I'll grab a few caps and add them to see the improvement.

For reference, I did use the 8 ohm driver, I did relieve the back of the front baffle and it is lightly stuffed. By 'lightly' I mean about a handful of pillow stuffing not compressed very much. If I should switch out to more or actual acoustastuf, I can do that as well, just let me know.

Thanks for the help!

Sandy.

[Wolf]

OK, bad assumption on my part regarding the cap acting only as a high pass filter. I really never have figured out this hobby for sure.

I'll grab a few caps and add them to see the improvement.

For reference, I did use the 8 ohm driver, I did relieve the back of the front baffle and it is lightly stuffed. By 'lightly' I mean about a handful of pillow stuffing not compressed very much. If I should switch out to more or actual acoustastuf, I can do that as well, just let me know.

Thanks for the help!

Sandy.

I used standard polyfil I believe, but the foam on the inner rear wall is very important. Since this has such small dimensions, the relections come much earlier and easier, so you need denser stuffing, and a damping layer on the rear wall. It sounds like you used about the same amount of stuffing as I did.

Just play around with the stuffing at your whim, and see what it does.
Have fun!
Wolf