Entering info into Hornresp

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TheBaronGroog

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Joined 2011
#1
Hi all,

I've been using BBP for years and find this a very easy programme for me to use. Recently I've decided to look into tapped horns and downloaded hornresp-to say I'm baffled would be an understatement! I'm dyslexic and not only do the abreviations for everything confuse the bejesus out of me but the lack of a visual "box" also make it hard for me to mentally picture how my inputs relate to the horn I'm trying to design.

I have two KEF B139 that I'm trying to design a horn for, for a fixed space under a sideboard at home, gross dimensions available are: 46.5"w x 16.5"h x18.75"d. I live in a tiny house-so please do not suggest any other designs as this is the only space I can allocate to the enclosure.

I plan to mount the drivers isobarically mag-2-mag (to use the mags as bucking mags, old CRT sat above enclosure). The face of one subwoofer will be at the throat, the face of the other in the mouth. The enclosure I mentally came up with is pictured (crudely) below and the T/S specs I've pulled of the drivers are below, averaged from the two drivers and then the net figure from wiring the speakers in parallel to get down to a 4ohm load for my amplifier:

Fs: 28.94
QMS: 0.44
VAS: 59.3 net 29.65litres
CMS: 0.4 net 0.2
MMS: 75.34 net 150.7grammes
RMS: 31.25 net 62.5
SD: 323.1cm2
QES: 0.645
RE: 7.12 net 3.56
BL: 12.3tm
QTS: 0.262
No: 0.215 net 0.1075
SPL1w/1m: 85.37dB net 82.36dB
SPL 2.83V: 86.03dB net 86.03dB

Now for the favour: could someone input the above with the dimensions below and take a screen shot of it? From there I hope my brain will kick in and I'll be able to contiue with the design-if not I'll know it's off to the nursing home at 33yrs old Box will either radiate straight into the room (on the floor) or into a bay window (this being preferable as my 7month old will be crawling soon and the 20"x15" opening would be large enough for her to disapear into!) NB: I plan to use .75" MDF all round-as I have a load lying around and little baby=BIG MONEY, so can't go all out on this 1st tester box.

Thanks in advance!
 

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#2
Hi TheBaronGroog,

Tapped horns are quite sensitive to variations in T/S parameters. I recommend to mount the drivers in a short tunnel that replicates their isobaric position in your proposed design, and than measure the T/S parameters of the combination as it will be actually used.

Have you looked at: Simple Tapped Horn Tutorial using Hornresp - AVS Forum ?

Well, back to work, maybe I'll find time to look at this tonight.

Regards,
 
#7
Hi TheBaronGroog,

There is a problem with your dimensions, the duct section widths plus the (5) board thicknesses add up to more than 18.75". Anyway, I stuck your fold into a drawing, and derived the input values for Hornresp.

As I do not have the T/S parameters for an isobaric pair of your Kef B139 drivers I entered the same parameters as bjorno (for a single driver).

Hope this will help.

Regards,
 

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#8
Oliver, you, my man, are a legend-virtual beer on it's way to you!

Yeah, I realise my 18.75" is out when the partitions are condidered-I do have a little more depth to play with-the enclosure will just encroach into the living room a little more. Looking forward to having a play with it all now🙂
 
#9
Hi TheBaronGroog,

For what it's worth, the enclosure seems to work fine as drawn, and the mouth is plenty large enough in respect to the Sd of the driver.

Let us know how you get along, pictures would be great.

Regards,
 
#10
Yes, seems to, quite a lucky guess then on my 1st forray into horns! -I'll try it with the drivers in the isobaric config-what differences would you expect to see?

I also ran sims in BBpro, in both clamshell and non-compound vented enclosures-using the same outer box dimensions and 15"x4" vent 160" long, see the results below, on set of results include port resonance-comments would be appreciated as the vented enclosures seem to have a 3dB gain over the TH, which I found odd! Other than output what would be the pros/cons to each design?
 

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#14
Hi all, dragging this one back into life-a few changes can be made as we've now got with the naughties and bought a 3D LCD tv🙂 (3D is cool, but TBH I'm not overly impressed with it atm GT5 works well, but 2D looks damn good too!)

So I now no longer have to go with the mag2mag isobaric design I was planning and have the desire to refine the "design" for two drivers.

So now I have 2x B139 and 46.5"w x 16.5"h x18.75"d to play with. I'll stick to .75" (18mm) MDF for construction, gives me 6.699cf or 189.7litres in new money to play with.

I'd like the box to play low, will integrate with my HT system, but will mostly use for music over film (blueray).

Anyone any suggestions?
 
#16
TheBaronGroog said:
..So now I have 2x B139 and 46.5"w x 16.5"h x18.75"d to play with. I'll stick to .75" (18mm) MDF for construction, gives me 6.699cf or 189.7litres in new money to play with.

I'd like the box to play low, will integrate with my HT system, but will mostly use for music over film (blueray).

Anyone any suggestions?
Click to expand...

Hi, Here is a ~18 Hz suggestion using 2xKef-B139b to import into HR and within the volume limit:

b🙂
 

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#18
Hi TheBaronGroog,

Double-click on L12 before trying to enter a value, the L12 label than changes to Con, and the value entry field is high-lighted. In other words you must select a taper prior to entering a value.

Regards,
 
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