Bass horn ideas again. A possible build. Need criticism.

[jwc]

Now that is possible.

I am definately hearing lower midrange coming through them though.

Active sounds attractive for setup purposes and ease of use but would rather not go that route.

Crossover or not. I still should be getting uninhibited signals from 80-200Hz (I Know this is not what you are referring to).

I will probably RTA to prove what I am getting as My terminology could be flawed and can't put things into words well.

I still can't believe I'm not getting this High SPL out of the bass bin like I thought.

SETI. Last Night I listened to the first two tracks off that disc you made for me at Hope. Great CD.

[Deang]

I don't see anything simplistic about an active setup. Well, you do get lots of buttons and knobs so you can screw things up on the fly. Either way you go, you have the same problem -- an enclosure, some drivers -- and a handful of unknowns. When you RTA that thing, do it out of network.

[Daddy Dee]

What is RTA?

[jwc]

DD

Real Time Audio Spectrum Analyzer

Lot of Folks use this software here:

http://www.trueaudio.com/rta_abt1.htm

[DrWho]

I just reread my post...my apologies if I came across knocking the dbb's. I think they're freaken awesome. I was just trying to throw a possible issue out there. And don't mind me and them altec comments - I just prefer a grittier tea is all []

It's hard to get an idea of what you're hearing with all the unknowns for us on our end - after only hearing your creation in a crappy environment. If they weren't so gargantuan I would have asked to hear them outside.

[D-MAN]

I still can't believe I'm not getting this High SPL out of the bass bin like I thought.

You are wired in parallel - or series? Series would explain the lessened volume (but so would 2-12" drivers compared to 2-15"s)!

Make sure they are wired in parallel (that means that the crossover would appreciate it).

If series, the efficiency goes to half, but the power handling is doubled, and the crossover point would be quite a bit higher (?!) than expected. I used to know this stuff!

DM

[Guest " "]

There is a lot of heat being generated with the power below 150hz.

Like most speaker manufactures, kappa really strectch's it's figures for technical data.

They report the kappa pro reaching down to 57hz, but if you look at the attached pdf, the driver is 12db down at 50hz with an spl rating of 85 db, while showing the advertised spl of 97db at 150hz.

This is not a knock on kappa, most high power woofers exhibit a steep rolloff at their lower end due to the mass needed to deliver their high power rating, 500 watts in this case.

Kinda like the k-33 vs the k-43 comparison. The k-33 sound great in a k-horn, LaScala, Belle, Cornwall but the k-43 would not sound as well in the k-horn and cornwall.

What we need is a kappa pro junior, a 12 inch cloth rolled driver that has 96+ spl down to at least 45hz. A 100 watt version would be fine. The extra 400 watt power handling ability is hurting the spl at the bottom end.

kappapro290-424s.pdf

[jwc]

Unfortunately, I'm worn out from work today and won't get to tinker further.

Mike again...no harm done. I'm doing some guessing here and hopefully get more useable info to report.

Kappas are in parallel.

The big question in mind is how do they sound compared to what was heard at Hope. What was heard at Hope was reproduced at Richard's house.

Whether you agree or not, the real jub has a "boom" to its sound. I mentioned this to Terry immediately after leaving Hope. It did this at Richard's house too. This is a good boom not a sloppy one. But realize, that is far from a La Scala. My Jub sounds just like a La Scala but slightly lower.

I think the Kappas are good drivers. Getting very clean sound. There is no punchyness or boom so far.

I'm eager to get more to you....I just have to catch up on sleep. Thanks for the input. I couldn't do all this w/o YALL's help.

jc

[jwc]

OK. I must be kiddin myself.

Here is the RTA with the jub speaker in the damn corner. After 200HZ I skipped some frequencies so just look at the peaks there. But from 200Hz below, every Hz incremented. Looks like a scala to me.

[jwc]

Same test run. Out to 500Hz scaled bigger. Remember after 200Hz, I was skipping some frequencies for time sake. Part of the RTA program.

[jwc]

Forgot to mention. Ignore the values of SPL to the left. They aren't calibrated. Therefore use graph as relative SPL.

[jwc]

Now here is a program on the software that runs a Cleansweep of all the freqencies at once.

Looks prettier.

[jwc]

low end cleansweep

[jwc]

Eat your heart out guys. Here is the Bass bin only with my low pass filter only. Where do you think the crossover point is?

I think Dean will like this one.

[jwc]

I think this should answer most of the questions asked here.

It is in the corner in a fairly big room. Mic is at the listening position....not at one meter.

I think it is seen that this does play out to 600Hz or better. Whether I place a different filter in there or not, I truely believe the sound of the kappas in there is how they are going to sound. The lowest of low end is how they sound whether I get up to 4th order low pass or not. Now we can throw all kinds of debates on this...but I think in general...I know this sound. I am sure I can make pluses to the set up with further work.

I think I need to change out the woofers and go there. Anyone think Of something critical I need to do before trying out the Pioneers?

[jwc]

There is an obvious weak area between 70-140Hz. This is where a Cornwall Bass bin shines.

[Guest " "]

Thanks for taking the time out for the graphs. I think you are right in that the driver is the limitation.

There is an obvious weak area between 70-140Hz. This is where a Cornwall Bass bin shines.

That's consistent with

"They report the kappa pro reaching down to 57hz, but if you look at the attached pdf, the driver is 12db down at 50hz with an spl rating of 85 db, while showing the advertised spl of 97db at 150hz. "

[Deang]

2.5mH on each driver?

They report the kappa pro reaching down to 57hz, but if you look at the attached pdf, the driver is 12db down at 50hz with an spl rating of 85 db, while showing the advertised spl of 97db at 150hz.

I think the plots somewhat reflect this. Sensitivity should be higher across the board.

I don't have the patience to go through the whole thread -- but do the T/S parameters of those Kappas closely match the parameters as shown in the JAES Paper? Don't know where I heard this or if it's true -- but I thought they used the K-31-K from the KLF-30 in the prototype. Roy?

Heck, it's been so long since I've read that paper that I can't even remember if it was with the passive or without -- or even if the unit you guys heard in Hope had it or didn't.

Finally, there is marked difference in sound between something built with MDF and something built with plywood. I mean, if you didn't use the same material it will be contributing factor in any difference you hear.

All of the differences add up to make a bit of a different speaker. That doesn't mean it won't sound as good, but it does mean it won't sound the same.

[Deang]

You need an out of network measurement. You want to see the raw response. When you put the network back in to measure the low pass only, don't forget to terminate the rest of the network with resistors.

[jwc]

Yes 2.5 inductor on each woofer. This is what sounded the best to me on the dbb's. Let's not start talking about those again.

I am not skilled enough to tell exactly how T/S parameters will effect the outcome of the performance in a bass horn. However, I understand the calculations made in the JAES paper which gives me a more fundamental understanding than most. I bet I have read that paper 20 times now.

Dean, I will do a raw response but I will do that just before removing the kappa drivers. The top hat is very heavy and I don't want to keep taking it on and off. Hopefullyn i will get the raw bas bin response tonight.

I do want to emphasize that the bass bin right now "sounds" very good. Those on the forum who like the sound of a Belle and a La Scala will find this very attractive. I am being critical by pointing out areas of concern. It is too easy for someone to post a custom creation here and get all fastinated with themselves and start making statements that really are too exagerated.

Now the network I have in there now Dean has a resistor accross the Autoformer just before going to the 2404 and 902 - EACH.

Yes I realize the 2.5 inductor on each woofer wasn't an attempt to crossover perfect. My thinking right now is that crossing over more accurately isn't going to change the low end which is my concern here.