Trying to design BLH for 25GDN-5 speaker, need help

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Hello, I'm facing difficulties by designing BLH with hornresp. I want to use old Russian speaker 25GDN-5 in BLH configuration (and add some tweeter), but in hornresp I get strange results. Maybe this speaker can't work in BLH? I measured T/S parameters by myself. I attach some screens with T/S parameters and that I get in hornresp. Maybe someone can help me? Or I need a regular vented enclosure for this type of speaker? :confused: Box should not be very big about 150L. Thank you.
Will upload photos soon!
 
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Here is proper photos. I don't need very low frequencies.
 

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GM

Member
Joined 2003
Well, mine's a bit bigger, though with these specs it should be a lot bigger if you want to smooth it out, get more low end. Still, its response is typical of acoustically small mid-bass scoop bins loaded with a high Qts driver.

Once the chamber is damped it will be sufficiently smoother and on a par performance wise for what some folks call 'half horns' and since it's basically just a big vent reflex I call them BVRs ;)

GM
 

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Thanks for your calculations GM ;) I will try to play with adjustments and try to lower inner volume. I have Fisher speakers which are about -3db on 85hz (they have label with frequency response) and they have enough bass for me. Maybe they don't worth to make it in this design? :confused: They (25gdn-5) sound really well for me, so open and have good attack with my aleph 60 clone. :)
 

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You're welcome!

Frankly, since building for deep bass isn't required, the attached small 'footprint' tower/column [MLTL around here] is what I would build/recommend.

Note that the dip, HF 'ripple' in the damped response is due to the bottom firing vent, so instead locate it on the baffle ~119.4 cm [i.d.] down from the top and they will dissipate to inaudibility.

This is just a generic alignment I do WRT height/driver offset since I/most folks want the driver up at an average seated ear height [~38" based on a ~3.8 cm thick bottom plate/plinth], so of course modify it to suit if desired.

GM
 

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You're welcome!

Frankly, since building for deep bass isn't required, the attached small 'footprint' tower/column [MLTL around here] is what I would build/recommend.

Note that the dip, HF 'ripple' in the damped response is due to the bottom firing vent, so instead locate it on the baffle ~119.4 cm [i.d.] down from the top and they will dissipate to inaudibility.

This is just a generic alignment I do WRT height/driver offset since I/most folks want the driver up at an average seated ear height [~38" based on a ~3.8 cm thick bottom plate/plinth], so of course modify it to suit if desired.

GM
Do speaker cabinet height is very important in this design? Can it be about 35W x 35D x 120H in centimeters? port should be only circle cut in front panel?
The main point from this speakers was to make something nice sounding and not standard box tower looking speakers like BLH's is.

Now trying to get something smaller with your first suggestion with BLH :)
 
Well, mine's a bit bigger, though with these specs it should be a lot bigger if you want to smooth it out, get more low end. Still, its response is typical of acoustically small mid-bass scoop bins loaded with a high Qts driver.

Once the chamber is damped it will be sufficiently smoother and on a par performance wise for what some folks call 'half horns' and since it's basically just a big vent reflex I call them BVRs ;)

GM

Make some modifications to your file and get almost same results with about 150L enclosure (first picture). What do you think? :)
And modify your MLTL enclosure, to go down to about 100L
 

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Do speaker cabinet height is very important in this design? Can it be about 35W x 35D x 120H in centimeters? port should be only circle cut in front panel?

It can if the aspect ratio is high enough to have 1/4 WL TL action sufficient to add enough damping to the vent to shorten it for a given tuning [Fb], so what does HR predict?

Yes, I typically design to just a baffle thickness vent when it's large enough to have a low vent mach.

GM
 
What do you think? :)
Like I said, I build /recommend alignments based on a well proven design routine; further, I allow some extra cab net volume [Vb] for some tuning/tweaking flexibility in case driver specs are off, some EQ may be used, whatever; so yes, they can be shrunk [sometimes significantly] if size is the dominate design spec and why I posted the HR files to adjust as desired. ;)

One thing I learned quite young is that making a cab internally smaller is way quicker/easier than increasing it and I hate 'do overs' when it comes to building stuff.

GM
 
Thanks for your replay GM, I see that I need to read and learn a lot stuff over internet about BLH, TL, and 1/4 WL, to build something that not disappoint me. Found some interesting designs with folded horns. But firstly going to read what 1/4 WL is and how to use it's advantages. :)

Like I said, I build /recommend alignments based on a well proven design routine; further, I allow some extra cab net volume [Vb] for some tuning/tweaking flexibility in case driver specs are off, some EQ may be used, whatever; so yes, they can be shrunk [sometimes significantly] if size is the dominate design spec and why I posted the HR files to adjust as desired. ;)

One thing I learned quite young is that making a cab internally smaller is way quicker/easier than increasing it and I hate 'do overs' when it comes to building stuff.

GM
 
You're welcome!

Except for [compression] FLHs, you'll learn all you need to know from these sites:

Resonances of open air columns

Quarter Wavelength Loudspeaker Design

GM

Thank you. The second link I know and read some stuff from it today :)

Found some interesting design and calculation in this page http://www.mh-audio.nl/TQWT.asp
Calculate and modeled TQWT in hornresp (if I do it correct) And I think I got some not bad results. Can you look through it one last time? It will be same results then folded? Or I need to model it like in this video https://www.youtube.com/watch?v=fjU__o5wEj8 ? Or maybe do not fold and make it like in hornreps drawing so it will be something like MLTL :)
 

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You're welcome!

Bad link, so: mh-audio Tapered Quarter Wave Tube

FWIW, with just Fs, Sd required, this is strictly a 'hit or miss' calculator, but at least gives a starting point for using a proper program, one of which is: Transmission Line

HR is limited to end loaded vents, so to get a more accurate response to any I've done, use this one to see how the driver, vent locations affect response.

Yes, if I had this software loaded I would have done what I call a ML-horn [tall expanding cab with vent near the bottom and driver down about halfway], whereas MJK calls it a ML-TQWT for both inverse and positive taper.

GM
 
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