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Speakerlab S30 tweaking

nerdorama

nerdorama

AK member
Subscriber
Hi,

I just got a set of these working after new surrounds on the the woofers and mids. They are interesting due to the Nestorovic woofer design. Very large magnets on both the 8" and 10" drivers. I've read the patent paper for these (#3984635) and found it interesting.

I've done some measurements and they can be adjusted for a very flat response from about 150Hz up, but they have a large peak centered around 60-70 Hz. Anyone ever played with these. I think they have some good possibility, but only if this peak can controlled. I will experiment myself, but would like to take advantage of other's experiences if available.

Thanks,
John
 
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Nice, how do they sound and how about some pictures?

I've never had a pair of these, but I've heard that they can really handle alot of power, 350 watts rms/channel max guaranteed safe amp power. My brother has a pair in his basement for the past decade in need of new surrounds - been trying to encourage him to either restore them or give them to me, but no luck so far. :tears:

Hopefully someone will have some experiences with tweaking these. I have the 1979-80 Speakerlab catalog which includes a couple of pages on the Speakerlab 30 model with the patented Nestorovic woofer system. I'll see if I can get a scan of those pages here. :thmbsp::music:
 
If against the wall, move them out away from the wall.

If in a corner, move them away from the corner.

If on the floor, jack them up off the floor.

Seriously.

If that does not work, a parametric equalizer... NOT a graphic eq.
 
Hi SpeakerLabFan,

Looks like we're near neighbors. I've got that catalog and several others. This is the 2nd pair of S30's I've owned, but the first pair was in bad shape so I played with them for a while and then trashed the cabinets. I have an old PC based measuring system that I've used to make some frequency and impedance plots recently. They look realy good in the higher frequencies, but that bass hump just doesn't sound good. I've also traced the xover schematic if you're interested.

Regards,
John
Kent, WA
 

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  • Speakerlab S30 xover panel sm.jpg
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Thanks, Paul,

I measured them out in the room sitting on a riser of about 6". When measured sitting on the floor, there wasn't a noticeable difference. I use a Behringer DEQ2496 in my system which works very well, but I'd like to try and mitigate the hump as much as possible by tweaking the speaker before I equalize.

Regards,
John
 
The model that got me into audio was the Super 7's- now those were impressive sounding speakers that would blow you smooth away....
DC
 
See if you can find an old Technics SH9010 parametric EQ. It's the perfect tool to drop that bass hump out. Set the center, set the Q, set the level... flat.

Great woofer concept, but when it finds a room with a sympathetic frequency that hump gets huge!
 
nerdorama said:
Hi SpeakerLabFan,

Looks like we're near neighbors. I've got that catalog and several others. This is the 2nd pair of S30's I've owned, but the first pair was in bad shape so I played with them for a while and then trashed the cabinets. I have an old PC based measuring system that I've used to make some frequency and impedance plots recently. They look realy good in the higher frequencies, but that bass hump just doesn't sound good. I've also traced the xover schematic if you're interested.

Regards,
John
Kent, WA
Click to expand...

Hi John,

Good to know another local AK'r and Speakerlab aficionado. :thmbsp:

Since you're in the Kent area, you might want to consult Paul Johnson who worked as a Speakerlab service tech in the past, runs theloudspeakerstore.com in Kent. I know he has a bunch of test equipment for speaker measurements which you might find useful. Good luck with the tweaking. :music:
 
S30 tweaking continues

SpeakerLabFan,

Thought I would do a short update. The peak I mentioned at 70-80Hz isn't really the case. It's more a dip from 80-125. I didn't measure higher before, but the 80Hz level is about the same as 200Hz. I added additional capacitance to the series cap (now have 420uF) on the 10" woofer and it seems to have reduced the suckout. I think the cap was causing a phase shift and the woofers were cancelling in that range. This change has brought the dip up to only about 2dB and the improvement in the midbass is very audible. When I get some bigger caps, I'll try again. The bass falls off pretty sharply below 50Hz which is surprising since I've read that this sort of woofer system has great low bass. If anyone has suggestions for tuning the low bass, I'd like to hear them.

I'll post more as I work on these.

John
 
Is the bass issue resolved?

I own a pair of Speakerlab 30's and haven't noticed the bass dip you describe. I noticed in the pictures you included that you have the bass fully damped. Not to sound condescending, but did you check that?

I like my 30's ($150 in a want ad) On my Onkyo A8700, and my Dahlquist M-909s (I picked up for $14) on my Carver "The Receiver."

Thanks,
Pat
Kirkland, WA
 
I added additional capacitance to the series cap (now have 420uF) on the 10" woofer and it seems to have reduced the suckout. I think the cap was causing a phase shift and the woofers were cancelling in that range. This change has brought the dip up to only about 2dB and the improvement in the midbass is very audible. When I get some bigger caps, I'll try again. The bass falls off pretty sharply below 50Hz which is surprising since I've read that this sort of woofer system has great low bass. If anyone has suggestions for tuning the low bass, I'd like to hear them.
Click to expand...

First, if the cap was old to begin with, it may have drifted out of spec. Would a new cap with the orig rating solve this without resorting to changing to a different rating?


Second, Any feedback on the BSR eq? Worth picking up?
 
With parametrics you have the ability to adjust the octave bandwiths/ spreads as well as the center hz frequencies- more and better flexabilities! SAE at one time made several nice 2 and 3 band parametric EQ's.
DC
 
There seems to have been a wider variety of Speakerlab speakers on the Seattle Craigslist over the past few months, including a couple pairs of 30s. I have never heard these but they sound pretty interesting. I remember reading about them years ago, but at the time I was not in the buying mode. Good luck with your tweaking.
 
Hi Susurus,
I didn't measure the capacitance value, but it checked good with an ESR meter. Based on that I assumed it wasn't too deteriorated but I can't guarantee it.

Pat,
I tried that damping in all three settings and none made a difference to the dip that I was measuring. Each setting made an audible difference to the bass, but at lower frequencies.

I haven't played with the S30's since my last post to this thread. If any S30 owner's in Speakerlab land would like to get together and do some listening and tweaking, I think it might be a fun time.

Regards,
John
Kent, WA
 
I'd like to read up on the principle behind the Nostros.

Is the idea that every frequency has an ideal cab size/passive characteristic, and by varying the midwoof's application by frequency, it's like a trombone--changes the effective chamber size to match every driven frequency? Or just by switching off between operation as an assist and a passive radiator?

Any link would really be cool.
 
Hi Susurus,

Look at the first post in this thread for the patent number. It's available online, or I can email it to you, and is a good starting point. The larger driver has a series capacitor which reduces the drive with lower frequencies causing it to become like a passive radiator but with a bit of drive to damp it. That's about all I can tell you. When I get home I can find my hand written schematic for the S30's and post it if there is interest.

John
 
S30 crossover schematic

Here's the schematic I traced from one of the actual units. A couple of values were hard to read so there are 1 or 2 question marks, but the topology is correct.

It's the 200uF cap in series with the 10" woofer with which I've experimented by adding additional capacitance.

John
 

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  • S30 crossover web.JPG
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