MLTL workbook...
...and here's a workbook for the layout of another MLTL. The example layout in this one is actually going to be built *very* shortly - it's a replacement subwoofer for my PC's multimedia system.
This workbook also includes an Export function that exports a HornResp import file using the values calculated in the workbook.
...and here's a workbook for the layout of another MLTL. The example layout in this one is actually going to be built *very* shortly - it's a replacement subwoofer for my PC's multimedia system.
This workbook also includes an Export function that exports a HornResp import file using the values calculated in the workbook.
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That it does, LOL. But the brace does "load" the entrance to the vent a bit.
FWIW, I've done some linearity tests on the POC3 loaded with the 3012LF, and the results are quite impressive. HornResp says that the 3012LF would start exceeding its Xmax at around 33.5V of input, and I tested it up to 40V in 3dB steps (-24dB to -3dB). The reduction in linearity seen in the top line in the graph (40V) might actually more of a measurement artifact as the mike may have been overloaded. The amp I used for testing, a car audio amplifier, is capable of delivering 1.2kW into 4 ohms, which works out to just over 69V, so I may repeat the test at slightly higher voltages when I find a means of preventing the mic from being overloaded without introducing too much error into the frequency response measurements.
BTW, I had a look at the 3015LF's specs, and it's a bit different to the 3012LF. The motor looks the same, but Fb is actually *higher*. Interesting choice by Eminence. I wonder what drove it?
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Attached is an updated version of the spreadsheet that includes an optimization macro and a macro to export a corresponding Hornresp import file.
To use the workbook to help fold a horn using the "MTH30" type fold:
1. Enter the driver's dimensions
2. Enter the external dimensions you'd like to use (height and width - depth will be adjusted by the optimization routine). Also enter panel thickness.
3. Enter S1 (desired throat CSA), S4 (desired mouth CSA), and L12 (driver offset from the start of the horn)
4. Hit the "Optimize!" button until the number below it says "0.00"
To input the values from the workbook into Hornresp:
5. Enter the correct values for any "cone compensation" you intend to do.
6. Change the "filename" to point to the "import" folder for your Hornresp installation
7. Update the driver's parameters, Sd, etc. in the workbook
8. Hit the "Export!" button
9. Import the file you just created into HornResp.
Next up - the Keystone
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So of course I find a bug in the workbook AFTER I upload the file (sigh).
Here's the corrected version.
I think I'm going to ask the mods to remove this thread with all the buggy spreadsheets and I'll start a new one that has links to just the non-buggy (or less buggy) ones...
It wouldn't be a very fair comparison.
The MTH fold is a single-expansion fold, which does limit what results you can get from it. Of the THAM and SS, both offer dual expansion as an option, but the THAM fold does offer possibility of a longer second expansion than the SS fold for a given cabinet depth. The SS fold however does offer an easy option for including cone compensation in the fold itself. If I needed the longer second expansion I'd go with the THAM fold, otherwise I'd go with the SS fold. If a single expansion can do the job, I'd go with the MTH fold.
I haven't seen a sim of the Cyclops (or subjected such a sim to analysis), so I can't say for sure. My fold does not waste any space at the front of the box like the Cyclops does though, so I expect that the sim'd path length will be slightly longer than the Cyclops. Still, this still is basically two short and small THs joined together and driven by one driver, so it's likely going to be very efficient, but not go very low (compared to other THs of the same external dimensions), and the sim'd response curves that I've seen for it bear that out - the CB-18 version starts dropping off at 50 Hz(!), which is quite high for a TH based on an 18" driver. I'd started this project some time ago and abandoned it, and I think now I know the reason why, LOL. Still, as I can't, or am not allowed to, do any *real* speaker work these days, I'll finish this one off.
Do you have link to the Hornresp sim for the original Cyclops?
The image shows where I've reached at the moment. There's still a lot more to be done. The eagle-eyes among you may recognize the external dimensions that I'm working with in this particular sim
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As expected, it seems to be a 50 Hz design, IMO tuned a bit high for an 18" TH. Of course, now that the fold is described via the workbook, it can be tweaked. I managed to get it down to a 42 Hz Fb with a bit of tweaking with the external dimensions given. To get down into the 30's though, which is what I'd be aiming for with a 18" TH, the box's width would have to be increased quite a bit, to just about 60". That's one wide (or tall!) box...
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My my, my myopic eyes see two external dimensions the same as the Keystone sub, and one between the original 45", and one smaller than the "B-Low" at 49.5"- but "close enough for rock & roll"- give the man a see-garrThe eagle-eyes among you may recognize the external dimensions that I'm working with in this particular sim
Cheers,
Titanium Cranium
My my, my myopic eyes see two external dimensions the same as the Keystone sub, and one between the original 45", and one smaller than the "B-Low" at 49.5"- but "close enough for rock & roll"- give the man a see-garr
Cheers,
Titanium Cranium
I thought he should get the golden cookie award.
I email them every once in a while.
Nope, as one TH, as I couldn't figure out how to sim two cabinets with one driver
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