Collaborative Tapped horn project - Page 383 - diyAudio
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Old 8th September 2012, 08:49 PM   #3821
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Thank you bjorno, I really appreciate your input. The thing is, for my use this isn't exactly what I'm looking for. I'm hoping to make the sub as efficient as possible (only because I'd have to start looking for big amps) while still maintaining superior sq compared to a badly done ported sub. The sub you recommended is great for someone who needs a small sub, but that isn't a primary factor for my build.

From what I've stalked around, bjorno, you tend to recommend a t-qwp and I've been playing around with a lot of different drivers. Does the "horn" part reduce subjective sq? I've read that the pre-pulse is more noticable and some other arguments that favor a tapped pipe system, possible with stuffing.
Does the improved SQ come from reducing the taper, with negative taper sounding even better? Obviously this comes at the cost of efficiency, and I've found out that some drivers do better in horns, and some do better in negative-taper enclosures. I might have to abandon the tangband as it really does like it's horn, and when going for a tqwp, the enclosure size and therefore efficiency get really small.
I can buy a cheap driver off a friend that I've been modelling with reasonable power handling and xmax, that seems to like a negative taper with a reasonable efficiency. You guys might be seeing some of that in this thread

Final question, is there any advantage for mass loading a tqwt other than extension, and are the effects detrimental to sq?

So much stuff to learn
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Old 16th September 2012, 09:26 PM   #3822
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Just reading all around this forum I've learned a lot, and realised that in a TQWT, the special magic is in the box, not the driver. So I simmed a cheap 10" car sub, and wow, does it look nice in hornresp (atleast to me, still learning)
Click the image to open in full size.
Picture contains some important points that I've been thinking, if something is wrong I'd like to know

TQWT is the way to go (for this driver) and I have to say thank you to everyone on this forum, especially bjorno as his time and effort is spread all around this forum, and his posts are always informative.
If no problems arise I will be building this next weekend, by then I'll have hopefully figured out the folding in sketchup.
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Old 16th September 2012, 11:09 PM   #3823
bjorno is offline bjorno  Sweden
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Quote:
Originally Posted by Skiivari View Post
Just reading all around this forum I've learned a lot, and realised that in a TQWT, the special magic is in the box, not the driver. So I simmed a cheap 10" car sub, and wow, does it look nice in hornresp (atleast to me, still learning)
Click the image to open in full size.
Picture contains some important points that I've been thinking, if something is wrong I'd like to know

TQWT is the way to go (for this driver) and I have to say thank you to everyone on this forum, especially bjorno as his time and effort is spread all around this forum, and his posts are always informative.
If no problems arise I will be building this next weekend, by then I'll have hopefully figured out the folding in sketchup.
Hi Skiivari,

Good work!

Despite the very high Qts value for a T-TQWT to start with I think if you stuff your box a little denser at the rear side of the cone(acoustical mass loading that shifts Qm down) the effective Qts would lower a bit and the inband FR would show up smoother.

Take a look at my simulation compared with your:The light grey color:

b

Ps: Keep L34 ~5 cm but in the reality: Add 10 cm to the simulated picture
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Old 17th September 2012, 12:19 AM   #3824
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Hi there B: Re post 3823, I've been wondering if a short L34 (like 5cm in your example with the driver partially exposed) is viable? Your comment is to extend L34 by 10cm (total 15cm) really blows-up the simulation. I gather that you have built some of these within the numerous builds you have done and have found this technque to be workable (?). Necking down the terminus ahead of the exit seems to have dramatic results. Is there some rule for minimum size termimus exit? I've been reluctant to build one of these, and pump 100+- watts through such a small opening (?). regards, Michael
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Old 17th September 2012, 01:20 AM   #3825
bjorno is offline bjorno  Sweden
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[QUOTE=j.michael droke;3167658]

Quote:
..Hi there B: Re post 3823, I've been wondering if a short L34 (like 5cm in your example with the driver partially exposed) is viable? Your comment is to extend L34 by 10cm (total 15cm) really blows-up the simulation...
Hi Michael,

Actually the internal length is not shortened but instead increased a bit(10 cm while(then) the original S4 is closed and replaced with a new terminus(Mass loading Port) that should be placed .at ~ 5 cm from the center of the driver front.
If you divide the area at that point with the driver frame width you will find a number must be close to 5 cm.This new location is then checked to be a good choise using one of MJK: programs

Quote:
I gather that you have built some of these within the numerous builds you have done and have found this technque to be workable (?). Necking down the terminus ahead of the exit seems to have dramatic results. Is there some rule for minimum size termimus exit?
I've built quite a few..My fingers and toes is not enough to keep track of all..
I usually try to pick a terminus(Port) area larger or equal to Driver Sd/3: This works fine with most large excursion Drivers I prefer (xmax< ~ 20 mm though)

Quote:
I've been reluctant to build one of these, and pump 100+- watts through such a small opening (?). regards, Michael
You shouldn't worry If you use a good driver. IMO,IME an Alu coned Driver is the best choise for an internally high pressurised T-TQWT/T-QWP.. and if the pressure is lower than 5000 Pascal's: The subs show no auible (IME) difference in SQ at low or at high SPL's (Of cource when working below x-max at any time).

b

Ps Sorry for my language, My spell checker doesn't worK despite reloading the proper plugins many times...
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Old 17th September 2012, 03:54 AM   #3826
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Hi there B: Re post 3825: Thank you for the information, and especially the explanation of exit port for TQ and TH enclosures, I never could find that in HR. I marvel at the community members able to communicate in many languages. I'm constrained to English and not very good at that. By the way, I hve trouble reading charts and graphs posted in multiples. When I blow them-up with the windows +150 or so, my screen resolution gets so bad that I can not read the numbers and text. Is there a trick or do I need a different computer with a better screen? ....regards, Michael
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Old 17th September 2012, 06:44 AM   #3827
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Quote:
Originally Posted by j.michael droke View Post
By the way, I have trouble reading charts and graphs posted in multiples. When I blow them-up with the windows +150 or so, my screen resolution gets so bad that I can not read the numbers and text. Is there a trick or do I need a different computer with a better screen?
Hi Michael,

1. Click anywhere on the composite picture to cause an initial expansion.
2. Move your mousepointer to the bottom left-hand corner of the expanded picture.
3. Click on the "four arrows" icon.

Kind regards,

David
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www.hornresp.net
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Old 17th September 2012, 08:36 AM   #3828
AndrewT is offline AndrewT  Scotland
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Quote:
Originally Posted by bjorno View Post

Actually the internal length is not shortened but instead increased a bit(10 cm while(then) the original S4 is closed and replaced with a new terminus(Mass loading Port) that should be placed .at ~ 5 cm from the center of the driver front.
If you divide the area at that point with the driver frame width you will find a number must be close to 5 cm.This new location is then checked to be a good choise using one of MJK: programs
I don't understand this description.
Can it be explained in a different way for me?
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regards Andrew T.
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Old 17th September 2012, 11:00 PM   #3829
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Default resolution

Quote:
Originally Posted by David McBean View Post
Hi Michael,1. Click anywhere on the composite picture to cause an initial expansion.2. Move your mousepointer to the bottom left-hand corner of the expanded picture.3. Click on the "four arrows" icon.Kind regards,David
Hi there DB: Fantastic, many thanks....regards, Michael
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Old 22nd September 2012, 09:20 PM   #3830
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Join Date: Sep 2011
Hi guys. I'm a bit tired now that I have had the wood cut, and I have a few questions

I chose 12mm BB ply for this project, 15mm for the middle baffle. Only one of my 400mm clamps has the needed 412mm range for gluing the rear panel on.. I have now been thinking if screws are the way to go for this build. I was thinking of using some screws with a flat head and maybe even a washer so that I could remove them later once the glue had set. The holes wouldn't hopefully destroy the nice-looking ply and there wouldn't be anything sticking out (visually).

I'll be mounting the driver with M6 T-nuts. I have no idea how to stuff the line, I'll probably go with what bjorno said, a bit more stuffing behind the driver, but should I damp the whole line or just the rear portion? I'll be using polyfill and obviously I get to decide but pointers from more experienced members would be nice

One thing I'm worried about is with the line width being 40cm the "height" of the line in front of the driver is only 3.5 cm, and the surround of the driver protrudes about 2cm.. It still has room on top and on the bottom of the driver and hornresp doesn't show major changes, at most lowering the tuning and efficiency a little.

I'll show you some pics at some point but later asI'm pretty sure its obvious from the integrity of the text that I am very tired :P (I only had to have the plywood cut THREE times.. protip: NEVER give dimensions over the phone.)
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