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Piccolo8, cab build for piccolo bass

#43
Arjank said:
This approach works good with midbass frequencies. Deeper tunings will require a rather long port which in turn will create a "hole" in the midbass frequencies and that's not what you want as a bassplayer.
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What's the ballpark tuning frequency of your piccolo bass cab, if you don't mind?
 
#45
Arjank said:
Deeper tunings will require a rather long port which in turn will create a "hole" in the midbass frequencies and that's not what you want as a bassplayer
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This design looks a little like the old bass "scoops" (rear-loaded horns). One feature of that design was, a hole in response at the frequency where the wave from the horn arrived out of phase with the direct radiation from the speaker. Is that what you're referring to above?
 
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#46
1n3 said:
This design looks a little like the old bass "scoops" (rear-loaded horns). One feature of that design was, a hole in response at the frequency where the wave from the horn arrived out of phase with the direct radiation from the speaker. Is that what you're referring to above?
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Yes, sort of. It's a combination of factors. 1st it's the standing wave inside the port/horn, since it's bigger and longer then a normal port the effect is more pronounced. 2nd it's indeed an out-of-phase phenomenon with the direct sound of the driver.
In the simulation I can add a parameter that determines the distance between the driver and port. If I add a distance of e.g. 12" the "hole" is almost gone, the problem is that the low-end output will drop....
In the "real" world the hole is less pronounced then on the simulation, especially when the in-room-reflections come into play.
 
#47
Arjank said:
Hi Duke, for that 8" driver it's approx 68hz.
I did some horn-reflex simulations for the new 12"Oberton drivers, best results gave a tuning of approx 60hz.
For the 15" drivers it's approx 55hz.
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It sounds like you found the sweet spot for the horn-loaded reflex design. Everything's a juggling of tradeoffs, but the more tricks in your bag, the better the chance of finding an optimal approach for a particular application. Since piccolo bass doesn't have to deal with Low-B, you largely avoid the midbass dippage, and still pick up 2 dB more low end broad-band. Very elegant. I'll have to add thorn-loaded reflex to my bag of tricks. Thank you, Arjan!!
 
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#48
1n3 said:
This design looks a little like the old bass "scoops" (rear-loaded horns).
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Yes - there similar, take for example an old Tannoy design
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Looks close - MOdel it first, then the best way to tell is to measure it. Some builder may take move a partition around, but within reason it's not going to change the audio path. It just won't work as good as the well engineered cab.

50 years ago this tannoy would have been leading technology. Today with better drivers the design can change and morph to take advantage of these new drivers. Still measurements are going to say what it is and how well it's doing it.
 
#50
seamonkey said:
Yes - there similar, take for example an old Tannoy design
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Looks close - .
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A horn-reflex may look like a short rear-loaded-horn but in fact it's "just" another take on the ported design which borrows some benefits from the horn designs.

seamonkey said:
MOdel it first, then the best way to tell is to measure it. Some builder may take move a partition around, but within reason it's not going to change the audio path. It just won't work as good as the well engineered cab.

50 years ago this tannoy would have been leading technology. Today with better drivers the design can change and morph to take advantage of these new drivers. Still measurements are going to say what it is and how well it's doing it.
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If you would simulate that horn in the picture in AJhorn 6.0 it'll show you a response very similar to what one would measure. I have seen simulations of AJhorn compared with real measurements and they were spot on.
 
#58
Arjank said:
If you would simulate that horn in the picture in AJhorn 6.0 it'll show you a response very similar to what one would measure. I have seen simulations of AJhorn compared with real measurements and they were spot on.
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I tried the demo. AJhorn looks to be incredible software!
Take a driver and model it in any number of cabinet types including the elusive horn. I'm glad to hear it is so accurate.
Now if it could only split out the cabinet designs and cut list ... ( asking too much :))
 
#59
oerk said:
Yessss, give them to me!

If you don't have any measurements, that's fine. I trust your engineering skills.
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I'll send the drawing with dimensions to you next week. I can also give you a panel-list, it's based on 12mm plywood, you have 12mm plywood in Germany? Also, since the cab is so small you don't need a table-saw to do the angles, a rough wood file will work (that's how I did the angles myself before I got my table-saw)
 
#60
seamonkey said:
I tried the demo. AJhorn looks to be incredible software!
Take a driver and model it in any number of cabinet types including the elusive horn. I'm glad to hear it is so accurate.
Now if it could only split out the cabinet designs and cut list ... ( asking too much :))
Click to expand...

Yeah, it doesn't spit out a cut list but it'll draw you the contour of the horn. You still need pencil/paper/ruler or Autocad to draw the cabinet.
 

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