Vituixcad2

[Doufuss]

OK I'm trying this program out. I realize I have to measure the drivers in box but have to start somewhere.

Uh, Eminence 3015 non LF and Alpha 6a

Here's some pics of the new design.

 

[Doufuss]

Or this... with a notch filter

 

[Doufuss]

Calling Foz, Aged Horse, Passinwind.

I'm looking to order parts and boot 'er up.

 

[Passinwind]

Calling Foz, Aged Horse, Passinwind.

I'm looking to order parts and boot 'er up.

Paging works better with an @ in front of our user names, which automatically prompts a TB notification : @agedhorse, @Foz.

I'll have a good look once I'm "woke."

 

[Foz]

Have you actually measured anything?

I think you are using the wrong woof - can you swap it for a 3015LF?

How are you mounting the mid = do you have a separate enclosure built into the cab for the mid... what volume?

 

[Doufuss]

Foz I have not measured anything yet. I do have the plots graciously supplied by Eminence for these speakers.

I really want to work with what I have on hand, which is two of the 3015 non LF drivers.

Yes the mid is mounted in a chamber - 0.14 c.f.

I want to build the crossovers based on the simulation, then test.

Then fine tune the cabinet and crossover.

 

[Doufuss]

I'm looking at a dats and omni mic unit from parts express for measurement, at that stage.

 

[Foz]

Is this a dedicated bass cab? If so I'd try the woofs alone = no mid / no xover and see how that shook out.

 

[Foz]

I don't see how that mid is hot enough to use rationally with that woof - am I missing something?

I think this might work even using both of your 3015's.

Eighteen Sound - Professional loudspeakers

 

[Doufuss]

That is a great mid. That's the one used in the fearful cabs.

I have a theory about using The Alpha 6 as opposed to the 18sound. The Alpha has a 93.6 db sensitivity rating whereas the 18sound has a 100 db rating.

The 18sound driver needs to be padded back to work with the 3015lf which has a sensitivity rating of 98 db. The fearful 15/6 cabs use 2.5 ohms on the leg and 20 ohms on the shunt. Granted, it's just a guess, but it looks like the 18sound is padded 4 - 6 db to make it work with a single 3015lf.

And so, it would also need to be padded back to work with the 3015 regular. On the other hand, the alpha 6 is used with the 3012lf with no padding at all, and the 3012lf has a sensitivity rating of 98 db.

In conclusion - use the Alpha 6 as opposed to the 18sound, and use no padding. My gut tells me it's a better match.

Of course, it's just a theory.

 

[Doufuss]

Secondarily, I want to make two cabs for modularity. The 18sound with both 3015's really sounds interesting, however.

 

[Doufuss]

Is this a dedicated bass cab? If so I'd try the woofs alone = no mid / no xover and see how that shook out.

Got that tee shirt.

It's a great cab. It sounds great with the exception of a really strong beaming problem. That's why I want to add a mid.

 

[Downunderwonder]

johnk_10 Streamliner cab used 3015 non LF and no mid or tweet. Then he razored off the dust caps and put on aluminum for a quasi tweeter set.

 

[Doufuss]

I saw that build. He wound up using the faitals iirc.

 

[Foz]

There is a switch in the mid pad of GB's 6ND410 mid loaded 15/6 xover... you flip the switch [up in the drawing below] to bypass the 20 ohm shunt resistor when used in conjunction with 15/sub = a single 3015lf needs a stout pad on the subject 18sound mid but dual 3015lf's need only modest padding on that mid driver.

It being that 3015's are more sensitive than a pair of 3015lf's I think you might be able to skip the pad altogether with that mid if you use both of the woofs you have and want to use. But we won't know unless someone builds it and captures a solid measurement.

But back the original question - I can't see how that alpha6A mid you have even shows up at the party in even a single 3015 scenario [that mid is down almost 7 dB from the woof = 94 dB versus 100.8 dB].

 

[Passinwind]

That is a great mid. That's the one used in the fearful cabs.

I have a theory about using The Alpha 6 as opposed to the 18sound. The Alpha has a 93.6 db sensitivity rating whereas the 18sound has a 100 db rating.

The 18sound driver needs to be padded back to work with the 3015lf which has a sensitivity rating of 98 db. The fearful 15/6 cabs use 2.5 ohms on the leg and 20 ohms on the shunt. Granted, it's just a guess, but it looks like the 18sound is padded 4 - 6 db to make it work with a single 3015lf.

And so, it would also need to be padded back to work with the 3015 regular. On the other hand, the alpha 6 is used with the 3012lf with no padding at all, and the 3012lf has a sensitivity rating of 98 db.

In conclusion - use the Alpha 6 as opposed to the 18sound, and use no padding. My gut tells me it's a better match.

Of course, it's just a theory.

IMO and IME it depends a lot on where you cross over and what styles of music you're going to be playing. I use the 18 Sound on a JBL waveguide in one DIY 'top box' cab and have to pad it way down (~8dB IIRC) for use with a single 15, but the pad soaks power the Alpha would need to see just to keep up, and the 18 Sound is just loafing rather than getting thrashed at the ~680 Hz nominal cross. And that also leaves me greater latitude for voicing tweaks. I developed the crossover via DSP and biamping for testing, and that 680 crooss point was the sweet spot for the voicing I wanted with the BMS woofers I'm using, which are definitely more like subwoofers. I used a padding network format that would make switching to less attenuation for two woofers pretty easy, but I've never needed to go there yet.

 

[Doufuss]

Thanks @Foz, @Passinwind. Lots to chew on here.

Because I have the Alpha6 and 3015's on hand, I'm pretty much committed to finishing the cab and running some tests. The worst thing that happens is I wind up with a box full of expensive paperweights in the form of inductors and caps

I didn't cross over to a frequency on either driver. But it looks like 770 Hz is the nominal crossover point. The 3015 is filtered much lower than the Alpha, somewhere around 575 Hz. Alpha is crossed around 800.

I ran the Alpha in Winisd in box and hit it with 100 watts and it's nowhere near xmax. Of course, that's not all there is to it, but important nonetheless.

A question - Do you see any danger to either amplifier or speakers? In terms of impedance?

And one more thing - I tried running the 18sound driver plots in the graph tracer to get some text and/or frd and zma files, but couldn't get a good grab. Can you tell me where I might find these files?

Thanks everyone.

 

[Foz]

Responses interleaved:

I ran the Alpha in Winisd in box and hit it with 100 watts and it's nowhere near xmax. Of course, that's not all there is to it, but important nonetheless.

My money's on heat death for your mid's coil - but maybe I'm wrong. Only one way to know for sure.

A question - Do you see any danger to either amplifier or speakers? In terms of impedance?

I avoid hooking my amps up to coils that I'm concerned are going to melt - maybe even do a dead short thing and throw flames.

YMMV

And one more thing - I tried running the 18sound driver plots in the graph tracer to get some text and/or frd and zma files, but couldn't get a good grab. Can you tell me where I might find these files?

You need to measure while the mid is in your intended mid box - with damping material in place.

Also you need to determine the spatial relationship of the drivers = given a flat baffle with flush mounting of both drivers, won't the acoustic center of the mid be in front of the woof's acoustic center [Z axis]? And obviously you are going to offset the drivers axially in both X and Y directions - this data needs to go in your model.

 

[Passinwind]

Thanks @Foz, @Passinwind. Lots to chew on here.

Because I have the Alpha6 and 3015's on hand, I'm pretty much committed to finishing the cab and running some tests. The worst thing that happens is I wind up with a box full of expensive paperweights in the form of inductors and caps

Nah, you'll still learn plenty and we all evolve as we go. I've had to stop doing DIY cabs for a while, but fortunately I managed to get some pretty decent results while I was actively building. Have fun and by all means keep us posted!

 

[Doufuss]

Responses interleaved:

I ran the Alpha in Winisd in box and hit it with 100 watts and it's nowhere near xmax. Of course, that's not all there is to it, but important nonetheless.

My money's on heat death for your mid's coil - but maybe I'm wrong. Only one way to know for sure.

A question - Do you see any danger to either amplifier or speakers? In terms of impedance?

I avoid hooking my amps up to coils that I'm concerned are going to melt - maybe even do a dead short thing and throw flames.

YMMV

And one more thing - I tried running the 18sound driver plots in the graph tracer to get some text and/or frd and zma files, but couldn't get a good grab. Can you tell me where I might find these files?

You need to measure while the mid is in your intended mid box - with damping material in place.

Also you need to determine the spatial relationship of the drivers = given a flat baffle with flush mounting of both drivers, won't the acoustic center of the mid be in front of the woof's acoustic center [Z axis]? And obviously you are going to offset the drivers axially in both X and Y directions - this data needs to go in your model.

I'll model with the offsets. That 410 is a stout driver, that's for sure. Almost double the power handling of the 6a.