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My turn to build JC's DBB


Rudy81

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  • 2 years later...

Just wanted to update this post...

 

I've been fortunate enough to inherit the DBB cabinets that were originally built by @Rudy81 in this thread... and were later passed on to @Thaddeus Smith.  I picked them up yesterday and they are in great shape. Build quality is excellent.

 

I hope to do one of two things with them... Either (1), look into finding a driver that will allow them to be used more like a subwoofer (20Hz - 80Hz range) and incorporate them into my existing LaScala HT setup. Or (2), get some K-33's (or similar) drivers and piece together a nice 2-way speaker with maybe some 510 horns on top for 2-channel. 

 

Either way it will be a couple of months before I can afford to start fiddling with them.  But when I do I'll create a new post to show my progress.   And if I ever get to the point of not needing them, I promise to pass them on to someone else here in the Klipsch forums.

 

Y'all take care...  Tony

 

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Tony,

 

Let us know how your project develops.  I seriously doubt you will be able to get any worthwhile performance below 40Hz.  Certainly the type of driver will have some effect, but I can't imagine getting reasonable performance 20-40Hz in that enclosure. 

 

I used them as a 2 way speaker with success, but as with most other speakers you just can't get good performance from 20-40Hz. It takes a subwoofer to cover that range in my experience. 

 

Good luck with the project.

Edited by Rudy81
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Tony,

Let us know how your project develops. I seriously doubt you will be able to get any worthwhile performance below 40Hz. Certainly the type of driver will have some effect, but I can't imagine getting reasonable performance 20-40Hz in that enclosure.

I used them as a 2 way speaker with success, but as with most other speakers you just can't get good performance from 20-40Hz. It takes a subwoofer to cover that range in my experience.

Good luck with the project.

Thanks... I hope to find out one way or another.

There are a few drivers out there that look like they would model well. Based on their T/S specs, with enough watts to use available excursion in a 6-6.5 cubic foot cabinet... as long as you're not wanting them to play out past 100 Hz or so.

I want to play around with WinISD a bit and see what kind of frequency response and dB level would be possible... Even it takes somewhere in the 600-800 watt range. If I can find one driver that works well, then adding 3 more, and corner loading both cabinets, may provide what I'm looking for.

If not, then I know they'll work with some K-33's... and I'll go the 2-way route. Either way they'll be fun to tinker with and listen to.

Tony

Edited by GPBusa
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To get down to 20 Hz with a capable driver...you will have to EQ below the tuning point of the cabinet. This may give you a bunch of distortion.

u could stuff the ports with a bunch of socks or rags and basically EQ a sealed cabinet.

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To get down to 20 Hz with a capable driver...you will have to EQ below the tuning point of the cabinet. This may give you a bunch of distortion.

u could stuff the ports with a bunch of socks or rags and basically EQ a sealed cabinet.

Agreed... And I hadn't thought of modeling it as a sealed cabinet. So I'll add that to the list of things to check.

The port length/volume was what I thought might be the biggest limiting factor. However, I'm not opposed to extending the ports externally to see what might be gained in low bass extension.

That's why I want to model a few drivers (with good excursion) to see what they can do in the existing cabinet within their RMS power limitations. And then adjust the port length/volume in the model to see what happens.

Even solid extension into the 30Hz range, with corner loading and room gain, might make it worthwhile.

Thanks for the feedback...

Edited by GPBusa
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Now you guys are getting some insight into why I ended up with the system I have now.  It is so difficult to find a single bass speaker that can really go from 20Hz on up.  The only way to  truly get to 20Hz is with a subwoofer designed to handle that range.

 

I agree with JC that you will likely end up quite a bit of distortion trying to get the cabinet down to 20Hz. 

 

IIRC correctly, I tried lots of different options trying to get down below 40Hz.  Just cold not do it.  I even tried sealing the ports and could not get satisfactory response.  Although, I did not try various drivers with better T/S parameters for bass.

Edited by Rudy81
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I for one have put to rest the idea of trying to get Hz down that low for music.  For HT yes.

 

I rarely watch Movies and when I do, I have little concern to what I'm hearing.  So I'm not a good critic there.

 

I listen to all kinds of music.  I have at times pushed my subs (4 KPT-684's)  to go lower than 30Hz.  I don't think they sound that great down there.  Most the pro 18 sub drivers vented really aren't even spec'd for that low.

 

..........

 

You have some cool bass bin cabinets there.  I would hate to see you modify them.  I have heard these style cabinets at 4 different locations mostly as 3 way for music.  They have never dissapointed me.

 

jc

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Whatever you do, dont modify those cab's... I hope to own them one day.

The only mods I might make would be to possibly extend the ports on the outside of the cabinet.

Or to slip in a triangular (removable) plug to either reduce the port volume slightly or completely... Depending on how things might model. My concern being that reducing the volume could drive up the port velocity too much.

If I ever get to the point where I can purchase the KPT-684's I want and get some 402 horns to convert my LaScalas to JubScalas... Then I'll pass them along as promised.

Edit: Just to add, my goals for lower bass would be to have them run only from 20hz-25hz up to 80hz. If I couldn't do that by playing with the ports in a temporary way. Then I'd go the K33 (or similar) route and try them as a 2 way speaker.

Thanks for all the comments... Tony

Edited by GPBusa
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Of the various subs I have used, I found the RSW-15 to be the best for the job of taking my mains from 80Hz down to 20Hz with minimal effort and little distortion.  Each one of my mains has an actively controlled RSW-15 to give me good low sound with music.  The RSW-15 in my experience, does not do so well below 20Hz. in the LFE arena for movies.  I do use my HT quite a bit for movies and rely on my dual SPUD clones for the LFE channel.

 

I would have gladly built some 684 clones, but if you look at the specs, they don't go down to 20Hz either.  I have heard the 684 and found that for home audio, the RSW-15 does a better job of filling the low end for music.

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