THAM10 - a 10" compact TH proposal

[martinsson]

Hello all

(This is a replica of the speakerplans thread, I hope that's ok)

I'we previously given 15" TH's a try (THAM15), and 6,5" as well (THAM6), and it struck me that there's one pice missing, something in between the Large and Small so to speak, and here is my sugestion :


Now, remember, this is a work in progress...

When loaded with the B&C 10NW64 the 2PI response at 1W looks like this :


The input window :


To show off, and really get the graph nerds going this is the response in 0.5PI 1W :


I want to post this in order get your take on it, remember it is still in development but i have reached a state where i feel it is prudent to go public with my findings in order to get some feedback.

I have an "further developed" proposal on my blog, but the only differances are that there is a distance panel (12mm) beneath the driver and a reflector in the front chamber, I will put it up here within short.

http://www.martinsson.cc/blog/

Best regards // Martinsson

[martinsson]

Here's the updated proposal, note the 45deg reflector leading inte to the front chamber, and also the 12mm distance plate at the driver.

My thinking is that maybe the reflector will help reduce turbulance noise, if any, and the distance plate with a circular cutout will reduce the risk of conedamage, and also (very perhaps) reduce compression effects.

[tb46]

Hi Anders,

I think that the 3-section model is not accurate enough for this enclosure.

Regards,

[Brian Steele]

Originally Posted by martinsson

I have an "further developed" proposal on my blog, but the only differances are that there is a distance panel (12mm) beneath the driver and a reflector in the front chamber, I will put it up here within short.

If you do actually build it, perhaps you could try out my "dogfood duct" idea to see if that would effectively deal with the first notch in the FR. It seems to have done so with my THAM15 lookalike, but I haven't been able to test it at high SPLs yet.

[martinsson]

tb46 : are you refering to the non linear, and rather brutal, expansion in the front chamber perhaps ?

Brian : intresting idea, I'll sift through the last few tech pages in the THAM15 thread and pick up the pieces, did that thread simply explode or what, very intresting and useful indeed, this one seems alot more dosile, at least this far

The intended uses for the THAM10 is not that far of from that of the THAM15, just scaled down a bit, as is the size 30x45x50cm (= 67.5 litres external).

When combined with a small top system, say 8"1", it would make up the foundation in a extremly compact yet quite capable mini rig suitable for small indoor live acts, useful respone in real world conditions would probably be something like 50Hz and upwards.

Two of these per side with a 10"1" top is another combo, and so on, so it is rather easily scalable if the need comes along.

Portabillity is key, and the output/size ratio seems to be beyond anything i have designed to date and you wont need a powerplant to make them come to life either, if the simulations are anything to go by that is.

But all this remains to be evaluated in the real world, sofar this is my maintrack sugestion, despite the rather odd front chamber area expansion.

[tb46]

Hi martinsson,

I was refering to Hornresp working with a given flare from S2 to S3 in the 3-section model. As I made that mistake on your THAM15 I just like to point it out:

Single sheet TH challenge

THAM15 - a compact 15" tapped horn

Naturally, we can just apply Beranek's law, and we're good. :-)

Regards,

[soho54]

I get something more like this.

This was done in a hurry, so please check it all out yourselves. The 1000cc Vtc is just a place holder, as that would need to be adjusted for the driver. S4 would need the same adjustment offset.

Here is an HR FR pic, SketchUp file, and HR data file.

[martinsson]

Brian : The risk of notch cancelations are allways present, in the THAM10 the lengts of the internal paths are shorter then in the THAM15, wich perhaps, maybe and so on, will push these flaws outside (upwards) the working range, above 200Hz at least.

tb46 : ahh good old Leo, he knew his stuff that's for sure yes the sim does not describe the box all the way, and I could re-design it into a more hornresp-like state, but that would not be as fun, or small for that matter

Soho54 : Thanks for the effort, but I cant seem to open the .skp file, and seeing as the .txt file data does not fit the THAM10 try 3 dimensions I asume is this another porposal ? do you have the possibillity to post it as a picure instead ?

[soho54]

Originally Posted by martinsson

Soho54 : Thanks for the effort, but I cant seem to open the .skp file, and seeing as the .txt file data does not fit the THAM10 try 3 dimensions I asume is this another porposal ? do you have the possibillity to post it as a picure instead ?

I'm not sure what to add.

The .txt file is about as close as HR is going to get to simulating that enclosure you posted. If you have problems with the mouth area then add the 31sq cm back in. It will not make a difference. It was there more as a reminder of the driver stuffed into the mouth of the horn. The Ap1/Lpt is the throat port you added, and the Vtc/Atc is the throat chamber you created behind it with the spacer, and the area in the cones dish space.

It is just a hurried run through to give you an idea of how to go about it. People can make what they will of it.


The .skp file is a Google SketchUp file. You would need the newest version of SketchUp to open it up.

[Xoc1]

I have plotted out the unfolded horn dimensions for the Tham 10 as drawn.
Martinson, your hornresp sim is very optimistic the schematic volume of the simple 3 section sim is bigger than the external dimensions of the box!
The tapered section as drawn is very linear. The last bend is a slight pinch point but only by 2.3 mm.
Suggest you make your 92.5mm dimension on you drawing 90mm.
When I entered the parameters back into hornresp I got a plot very close to Soho54's post 7 plot. Unfortunately the efficiency looks quite poor - comparable with a reflex box of the same size. I tried to improve the cabinet but I think a radical rethink may be in order.