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jwc

Dual 15 inch Corner Bass Bin - Cornscala dbb

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Would it adversly affect the sound if the two side ports were the full height of the bass bin but only half the width?

As long as you maintain the same surface area to length ratio of the port, then the tuning shouldn't change. However, the more circular the opening, the less port chuffing you will have. However, if the slot port gets too narrow, then it's tuning point will start to move lower and compress as you increase the SPL.

Basically what's happening is the port isn't able to maintain a coherant wavefront due to friction on the surfaces inside the port. This results in random motion and is the source of the chuffing.

At least that's my understanding of it....wish I could point you to a resource, but I can't think of one off hand.

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Claude. Not sure what your post is referencing too.

In the beginning of this thread...the initial network I used was a Type A network with an extra 2.5mH inductor.

jc

I have had both the A and AA networks. They used the same 2.5 mH choke on either one since day one. So I would just twin 'em up. What's the problem?

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What's the problem?

Claude, there is no problem. I have done what you said and don't disagree. You have brought up a discussion that was discussed years ago on this thread. I wasn't sure why you brought it up again...Am I missing something?

jc

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What's the problem?

Claude, there is no problem. I have done what you said and don't disagree. You have brought up a discussion that was discussed years ago on this thread. I wasn't sure why you brought it up again...Am I missing something?

jc

Not at all, I'm missing something. Looking up the date of the original thread.........duh...........sorry.

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Not at all, I'm missing something. Looking up the date of the original thread.........duh...........sorry.

These come back to haunt us now and then... [:|]

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Hey who is that in your avatar?

Big Smile Some crazy college kid I used to know.

tc

Reminds me of someone who gave me coolaid and a brownie and said have a nice day [:D]

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Hey who is that in your avatar?

Big Smile Some crazy college kid I used to know.

tc

Whao, close call. For a minute I thought old Charlie Manson escaped[:o] Who loves ya buddy[;)]

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I have received some emails about interest in the triangular port version of the dbb.

I want to remind you that the way it is ported now is like an early cornwall that has that "hump" in the frequency response tuned to about 45Hz. Some like that.

You can flatten that out by changing the port.

So to venture into changing the port and also consider using the Eminence Kappalite 3015 LF, here is brief description of what you do. The K33/Crites or the Eminence driver can be used here:::::

I would bring the baffle out flush with the side and top panels or leave the way it is. This isn't a big deal but if you bring out to the baffle you gain a little volume and have more room to lengthen the port. Make note that the horizontal panel in the middle of the cabinet used to split the cabinet and for bracing may have to be adjusted too.

Obviously, don't cut out the rectangular ports on the baffle and don't make the cuts for the rectangular inner portion ports (as seen in the CAD plans on this thread).

Instead....cut triangles off the 4 corners of the baffle as shown in the picture. The two short arms of the triangle are 8.75 inches and the long edge is 12 3/8. The port shelf will extend back from the 12 3/8 edge. So there will be 4 triangular ports.

Now the length of the port is a choice you will need to make for what you want. For a total port length of 9.5 inches, this will be similar to the cornwall and tuned 44-45Hz. This will give you a little "hump". The longer the port will flatten out the response and lower extension. Port total length of about 12 inches is about 41Hz tune. This is flat. Note the the baffle is 3/4" thick with a port shelf behind it. So for a 9.5" port.....that is 3/4" baffle plus 8.75" "triangular shelf cut behnd the baffle. NOTE: I have not heard this. This is all theoretical with software. I believe all this "works" but I can't verify the "sound" made.

jc

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Have you had a chance to listen to the Kappalite, JC? What were your impressions?

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Have you had a chance to listen to the Kappalite, JC? What were your impressions?

Not in the dbb's.

I have them in some Titan T48's subs and like them there. I have no experience with them as bass reflex LF. Spec looks good to me.

I will soon order some Kappalite 3012 LF for a different project. Might have a "similar" sound?

jc

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You doing a bass reflex with the 3012? I would imagine that they would at least sound similar.

I'll have to do some reading on the T48 subs. I take it you're enjoying them?

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I have received some emails about interest in the triangular port version of the dbb.

I want to remind you that the way it is ported now is like an early cornwall that has that "hump" in the frequency response tuned to about 45Hz. Some like that.

You can flatten that out by changing the port.

So to venture into changing the port and also consider using the Eminence Kappalite 3015 LF, here is brief description of what you do. The K33/Crites or the Eminence driver can be used here:::::

I would bring the baffle out flush with the side and top panels or leave the way it is. This isn't a big deal but if you bring out to the baffle you gain a little volume and have more room to lengthen the port. Make note that the horizontal panel in the middle of the cabinet used to split the cabinet and for bracing may have to be adjusted too.

Obviously, don't cut out the rectangular ports on the baffle and don't make the cuts for the rectangular inner portion ports (as seen in the CAD plans on this thread).

Instead....cut triangles off the 4 corners of the baffle as shown in the picture. The two short arms of the triangle are 8.75 inches and the long edge is 12 3/8. The port shelf will extend back from the 12 3/8 edge. So there will be 4 triangular ports.

Now the length of the port is a choice you will need to make for what you want. For a total port length of 9.5 inches, this will be similar to the cornwall and tuned 44-45Hz. This will give you a little "hump". The longer the port will flatten out the response and lower extension. Port total length of about 12 inches is about 41Hz tune. This is flat. Note the the baffle is 3/4" thick with a port shelf behind it. So for a 9.5" port.....that is 3/4" baffle plus 8.75" "triangular shelf cut behnd the baffle. NOTE: I have not heard this. This is all theoretical with software. I believe all this "works" but I can't verify the "sound" made.

jc

JC thanks for the info more people should build these I love mine ,not that I don't love my La scalas as well, but I love lots of LF and these are the ticket and can damage a houses foundation.

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This is the second time I've gone through this build and it just deserved a bump. I know Rudy is getting ready to travel down this path and it would be really great to hear a version of these next to some modified K horns, Jubs or Jambs, just to hear the differences. Are any of these traveling to Hope???

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This is the second time I've gone through this build and it just deserved a bump. I know Rudy is getting ready to travel down this path and it would be really great to hear a version of these next to some modified K horns, Jubs or Jambs, just to hear the differences. Are any of these traveling to Hope???

IIRC, JC took his first DBB to one of the get togethers but there was an issue with the room they were in. I think that comment is here somewhere. I have read so many threads on the DBB, the Jamboree and Jub that my head hurts.

Pete, you will likely hook up the Kappalites first, let us know what you think. I do know they are light as a feather!

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Ok so after saying the same thing on a few threads I finally am going to sum up what I would like to do and see if this seems reasonable.

I have a wdth restriction of 22" width wise. I thought of building a DBB but then saw the 30" width. I have always liked the triangle port since I saw them on the KPT-684. Now the 684 is only 24" wide and has 18's so could I do something like yours/684 using 15" and get the width down to 22" and achieve similar resultsto your DBB?

I originally thought I would have to use 12" drivers. SO seeing zero T/S on Bob Crites twelves I asked him something similar and he mentione building the KLF-30.

So what do you suggest. Great thing about Crites twelves is they are very cheap and I COULD afford to do the dual 12 per cabinet around X-mas time other wise I will have to wait alittle later. Unless there is a suitable Beyma driver which I can usually get pretty cheap here.

Lastly when looking at the 684 and other cabinets crossed at 800hz are the woofers both doing up to 800hz or is the bottom woofer being crossed lower and being used as a helper woofer?

Thanks for any help and sorry for posting similar posts in others threads.

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