Dana Moore's (D-Man's) SLS project well under way

[popbumper]

Gonna hook it up this weekend, I will give some initial impressions then. This will NOT be an ideal setup, but it's a start. More to follow.

Chris

[D-MAN]

Chris evidently has the patience of a saint!

You're KILLIN' me, man!

Dana

[JohnA]

Waay Cool! I wish one of you lived closer to me. We could have some REAL fun!

[D-MAN]

I probably shouldn't pre-emp Chris, but this is killing me.

I haven't heard from him recently, but I did talk him into hooking it up for a test run last week before he has finished it completely. Unfortunately, he only built one cabinet, so that makes it sort of difficult to discern its qualities.

On my advice, he took the woofer output from the network of one of his Cornwalls (disconnected woofer) and ran that through a port tube on the S-LS to the Crites CW1526C woofer on the narrow 3" wide slot (like the La Scala) motor board. The Cornwall in question was sitting on the top of the S-LS. And then he fired it up!

I think he expected a big change compared to a Cornwall. So did I, but I should say at this point that I have never actually heard a CW ... I was telling him that the S-LS should be twice as loud as a CW. I figured the CW's at 99db or there abouts, figuring the driver's 96 db + 3 db for the port-loading. So the fault is mine.

He was somewhat disappointed in that he said he couldn't really hear a difference between the single S-LS bass bin and the Cornwall(s). That is depressing considering all of the work that goes into building one, isn't it? His report initially suprised me too, until I looked up the published sensitivity of the CW III. I'm presuming the low-end of his 1986 (?) CW's to be about the same.

CW = 102 db +/- 2db 34-20K (Holy Cow! how is that possible?!)

S-LS = 104 (Klipsch says 105 db for the La Scala +/- 5db, so I am conservatively estimating 104 db) [this also assumes a 96 db Klipsch or compatible driver, narrow slot, hence the CW1526C]

That would be a net change of +2 db in SPL, which is not actually discernable by the human ear by everything I've read... Bottom line is that there is nothing shabby about the CW response specs. Literally, a Khorn bass bin would have trouble topping that, seems to me, in the case of ONE and not a pair, but that is a matter of conjecture. Most of this is a matter of conjecture, come to think of it.

However, the S-LS seems to work fine using the CW crossover (6db slope at 800 Hz), and that is what I expected due to the throat configuration. Also, if the low octave is indeed comparable to a Cornwall, the reflex ports are also doing what they are supposed to. The lowest octave between the two, in fact, should be exactly the same, there should be no difference there. The difference would be in the 60Hz and above range.

In actuality, I'm pretty happy with the reported results after I found out what was going on, although I feel bad for Chris feeling disappointed. But what the heck, he should have built 2 and AVOIDED POSSIBLE DISAPPOINTMENT! Just kidding, Chris. I should have done my homework when you asked about CW's and not set you up further for disappointment. I appologize for being an idiot.

I am willing to bet that he would likely be able to hear a discernable difference (i.e., the benefits of horn loading) if he could listen to a pair at the same time instead of a single. I don't imagine that you could hear much of a difference with only one unless some very careful listening is done. But, like I said before on other threads, my rule is NEVER test-listen with one of anything! Done it myself and got burned.

This episode has given me new respect for the output of a Klipsch Cornwall, though. That is a suprisingly efficient bass-reflex enclosure if I can't beat one hands-down on the FIRST LISTEN with a well-designed (if I do say so myself) horn! Remember, this is only ONE bass bin by itself, and, in Chris' case, it's using Klipsch parts (or compatible) so it is, in essence, entirely compatible in every sense of the word.

The listening results of a single S-LS bass bin compared to a Cornwall? Inconclusive at present. Wish it were conclusive, but I'm not there and I'm not the one doing the listening.

I recommended to Chris that the next listening test should be using the wider 6" slot motor board and see if the efficiency goes over the +3db point, which SHOULD be discernable even with a single cabinet. Also I would expect the upper frequency range to increase with the wider slot.

Then perhaps, a stronger woofer might be in order, but then the CW network and the tweeters would "go out the window", so to speak. It depends on what Chris wants to do. Sounds to me like he wants to go industrial strength, and that certainly means a using a more efficient driver. I have one in mind, 99 db.

I certainly want happy, satisfied DIYers, and don't want anyone to ever be disappointed for any reason, even the ones I can't do anything about. However, it seems that the design is doing everything its supposed to, so I'm actually pleased (now).

DM

[Coytee]

Nice job & nice looking!

Question for you (or D'man??)

The top hatch is presumably going to be drilled & screwed down. Would it be possible to (when making the initial cuts) cut the lid with a 45 degree angle and the two sides with a matching 45 degree angle and then SLIDE the hatch on like a wedge?

Just wondering if you could do that & hide any screw holes. I figure if the wood is in plywood then it might be possible. If it's in MDF, I don't think it would hold up over time.

Just curious, I know that would cause some issues with cutting the angles and having them mate up nice & tight without being TOO tight.

[D-MAN]

My original intention was to cover up the top with a high-frequency cabinet in the standard manner.

DM

[IB Slammin]

Dana,

Many of your points are well recieved by Slammin, the CW bin fan of all fans.

.............Bottom line is that there is nothing shabby about the CW response specs. Literally, a Khorn bass bin would have trouble topping that, seems to me,..........Soooooo glad you said that and I did not..........[]

That said, and you said it,.......IMHO, a new (horn?) design to equal the Good Points of a CW bin, and minimize the the Not So Good CW reflex points , would be a speaker bin with less bloom (less, but not without a degree of controlled bloom) and a more ACCURATE LF PRESENTATION.

So, my question to you and Chris POP is........How much of an improvement in LF accuracy, does the SLS have, while still displaying the slam factor of a reflex?

Best Regards,

tc

[D-MAN]

Don't ask me! Chris has the only one in existance! And I've never even heard a CW...

I was only trying to beat the La Scala (which I have heard - I wanted to buy them, even) by increasing the bandwidth and reducing the footprint.

Dana

[popbumper]

Guys, let me first apologize for the "hold-out". To be quite hionest, with Christmas on the horizon, I have had LITTLE time to do anything. Yet all is not lost.

LAST NIGHT, I swapped out the 3" motorboard for the 6" motorboard, and gave it a roll. Now I need to preface this with some - er - "caveats" as I quite openly am note experienced at testing/listening, using my ears as the only instrument. Here is where you experienced audio guys crucify me.....

Regardless, I hooked up the bin and added a single 2.5mH coil in series to "knock off" the high end and roll it off. While the bin seemed to "perform" reasonably well, I still do NOT have the top panel sealed off airtight as it should be, so I know I am lacking here. Additionally, I don't have the luxury of a "test space" or a mono switch to really drive it properly. While it DOES seem to have a SLIGHT edge over Cornwall, it nonetheless strikes me as not having a lot of "extra slam" as it were. Again, forgive the loose terminology - this is a non-scientific approach at best.

Now here is one thing that Dana told me during this whole thing - and I was surprised (or dumb, as I never realized it) - that it was really a Lascala bass bin. My first thought, sadly, was "ugh" - since I personally have no love whatsoever for Lascala. When I heard the NEW Lascala at Hope, compared to everything else, I HATED it - the bass was loose and sloppy (again, my opinion) compared to the corner horn and Cornwall III...and apparently it's an IMPROVEMENT over the original.

One other thing - and maybe someone can parallel me on this - but listening to a bass bin by itself is REALLY hard to evaluate. Without having another cabinet, I felt it was not a good test (yes Dana, I apologize - my bad) - AND, it really needed a top end on it to make it "listenable". I also do not know which tools are typically used for this, nor do I have any.

SO....in my completely (and likely utterly useless) response to many, let me at least say that the exercise thus far has been rewarding, though without the technical merit it deserves. What next? Well, either the bin needs to go to someone with some valid measuring experience, OR, I need some suggestions as how to approach testing so that we can get some meat out there to satisfy the real questions. Guys, I'm perfectly capable - and willing to listen to suggestions on what to do, how to listen, how to measure - but I need some guidance. Perhaps this project would best have been served in some more capable hands - being a wood guy, I did fine; I'm just uneducated on how to properly test and measure speakers. And no, I don't have an anechoic chamber handy.

PLEASE do not judge Dana's plans on what I have said, that would NOT be a fair assessment, and I feel he deserves the answers he needs.

Chris

[D-MAN]

Chris, my advice is build the second cabinet. You need to cut me the parts anyway (!), and a pair is much easier to "get rid off" (if you want to go that route) than a single (take it from me, I know whereof I speak). Otherwise, stopping with one, you are going to make me look bad.

However, you could send me the flat kit for a pair, and all is forgiven!

But seriously, yes, a single bass bin is literally listening to a woofer, and nobody can evaluate that very well by ear. They sound pretty HORRIBLE like a subwoofer without any high end. Man, I wish I was there to help.

Well, it's a learning experience for both of us. But really, a pair, build a pair. I think you'll be suprized.

I have a pair of ALK ES at 600 Hz specifically for that driver which I can loan you, (now there's a possible deal) if you have the horns/drivers for it. I've got those, too (another possible deal). But you'll need to build a PAIR first.

That reminds me, RICK (3dzapper) you have PM.

Dana

[popbumper]

Dana:

Thanks for getting back. Your quote "They sound pretty HORRIBLE like a subwoofer without any high end" summed it up well.

Regardless, I could hear the crickets chirping after my response, which is typical for when I write most anything. I will cut and assemble a second bin over the Holidays. I will also be in touch with you via email or phone, we have lots to talk about on this stuff, and I want it to be a success. Thanks for the support.

Chris

[D-MAN]

Dang, that thing looks sexy! I want a pair BAD.

DM

[jwc]

Chris.

You may want to try and plug the ports and see if it sounds anything like the La scala.

When I decided to start making bass bins, I knew that I would need a top end and a crude network to get an idea of what the sounds would be like. Other than that, there is no other way that I know that you can "test" a creation in the home.

One possibility is to purchase an Altec 811 or 511 with a driver that goes out to 20K HZ. That way you can just throw on the top and with a crude network to "test" it.

I forgot. Do you have a K33 in there? If so, Make an ALK Jr with ability to change taps on the squawker and tweeter as well. Or just buy one of Al's attenuators. The 2.5mHy inductor you have will "crudely" roll of the k33 somewhere in the 400-600Hz range. I personally think it is higher than that from my own crude testing.

Notice I used the work "crude" alot here. That is what we Home grown speaker builders need to get used to sometimes for initial listening/testing.

jc

[Coytee]

I've always wondered if someone like Roy (or PWK in his day) can hear one of these raw bass bins and, know right off the bat if it's at least in the ballpark.

I was amazed to find out how much the raw bass bin sucks in its sound, without any HF support.

[]

[D-MAN]

Another cabinet will certainly clarify the LF output in that it will be twice as much of what you are getting out of one, with no muddling, mixing or blending, and no covering up.

Any response abberations will also be twice as loud and will easily stick out.

I wouldn't bother playing with the ports. WIth the ports plugged the back chamber is going to be far too large to be anything but floppy-sounding for that driver. That would be what I'd expect.

The Vb is sized to allow the ports to resonate at the appropriate frequency.

Chris cut the ports at 8" length, they could go as short as 7" which is where most djk-modded LS owners seem to prefer, which is somewhere in the high 30's. I would say that 8" is probably fine. I'd have to hear them to be sure.

No, I wouldn't mess around too much until I had the second cabinet. One is just giving him a bad taste. Messing with it won't make it taste any sweeter, because I don't think that there is anything wrong, technically speaking.

I don't think that they are going to sound like a La Scala in any event because the horn is configured differently, enough to make it its own thing. The mouth size is the same, but the horn length is longer. There are hard reflectors in it that the LS doesn't have, and it also goes higher in response because of the throat channel configuration as well as a different back chamber size (and ports). That alone should be an indicator of the difference in horn configuration and related performance.

ABOUT THE LA SCALA -

And speaking of a La Scala, I heard them twice in two different placements, same cabs, same equip, same room. One placement I thought they sounded IMPRESSIVE and one placement they made my ears bleed. I know that if properly setup mine will NOT make your ears bleed regardless of placement, but that is all network and mid/high renage horn/drivers, seems to me. That is easily overcome, I already have the network and drivers.

Remember, the S-LS are based on my corner horns, they just also happen to use the folding pattern of the LS (and have the same nominal Fc). But then, the EV Eliminator uses the same fold pattern and many others (vertical instead).

Instead of thinking that the S-LS as just a fancy La Scala, think of it more as a folded Altec A7. Couldn't use the same Altec driver because it needs more internal volume but I might try one just to play around with one, they are great mid-bass drivers. But the difference is that the S-LS can make use of the great mid-bass capability of a driver like that, which would literally be a waste in a real La Scala.

No, I don't think it will ever sound like a La Scala. Bass-wise, it goes lower, it goes higher, and takes up less floor space. The idea is to outperform the La Scala, not sound like one.

Maybe a ported "Little Bast@ard"? Nah...

DM

[popbumper]

Thanks guys, superb feedback!

Dana, I am setting up the CAD RIGHT NOW to recut some panels for the second speaker (modified panels since I had some extra tops/bottoms to play with). I am also going to build the divertor differently so that it is not 27 pieces of MDF - that was a real pain and I don't wish to revisit it. The first cabinet was a "process oriented" exercise; the second will be a refinement of the process and a more accurate build. I will definitely keep you up to date on progress - and with "Holiday week" next week, I am going to devote some more time to it - hopefully.

JC - the woofer is the Crites K-33 replacement (CW1526) with a cast frame.

Chris

[D-MAN]

Chris, I thought about that on the throat splitting wedges. I make them out of 4x4 solid fir which is how the plans describe them, but they could be made from 3/4" ply, open back, open bottom, with a top (or bottom, respectively) to seal them. Well glued in, they should be sealed completely.

These would be the 4" wide x 6-1/8 45 degree "front pieces" with a single triangular top or bottom piece inset flush to seal of the "interior". When glued and screwed in place, no soundwaves can get in behind.

3 parts per wedge, 6 required total.

I also will email you an alternative full-height solid wood version of the wedges, but I figure that will take a bandsaw to make. Easily, that is.

Dana

[D-MAN]

Also, being that its a 90 degree wedge, you could just butt-joint them instead of the miter I showed above. Even easier!

DM

[D-MAN]

Where I'd like to go with it is this, but I can't draw it very well. Where's Armando when I need him?!

!

[D-MAN]

Here's where I want to go...

DM