elif Posted October 7, 2023 Share Posted October 7, 2023 Once upon a time I measured a set of impulse responses of the horn and drum of my 142 Leslie. They were measured at each of 16 angles of rotation. It was about twenty years before I did anything with them. After I retired in 2018, I worked on the simulation for three months, eventually porting it into a TI TMS320C6748 low-cost development kit (floating point DSP). I was going to make myself a Leslie simulator. Then just after that I bought a Ventilator. Why build what you can buy right? The thing is, though it could use some work, I like the Octave simulation better. To me, it sounds more like a Leslie in a room, probably because it was from a Leslie in a room, my living room. The following is a link to a google site I created to allow someone to audition these. The mp3s are hosted on my google drive. I presume there should be access to them. Leslie speaker - Octave sim Quote Link to comment Share on other sites More sharing options...
KuruPrionz Posted October 7, 2023 Share Posted October 7, 2023 I couldn't get the 1st track to play, silence even if I moved the cursor into what should be the sound track. 2nd track played and sounded great, I like it!!! Kudos!!! 3rd track also sounded very good but I preferred the 2nd track to be honest. Well done. Quote It took a chunk of my life to get here and I am still not sure where "here" is. Link to comment Share on other sites More sharing options...
Tom Williams Posted October 7, 2023 Share Posted October 7, 2023 First track played for me, as did the other two. Octave sounded quite natural -- I'd happily use it. Vent seemed to have (add?) a little more lower-mid presence than the octave; that felt a tad warmer. I'm quite happy with my Kurzweil Leslie, but I think both Octave and Vent sound even better, especially in isolation from the noise of a band. Amen to KuruPrionz's Kudos! Quote -Tom Williams {First Name} {at} AirNetworking {dot} com PC4-7, PX-5S, AX-Edge, PC361 Link to comment Share on other sites More sharing options...
Mighty Motif Max Posted October 7, 2023 Share Posted October 7, 2023 That sounds really good! All three files work for me - I find I like the sound of the Octave sim best. Quote Yamaha: Motif XF8, MODX7, YS200, CVP-305, CLP-130, YPG-235, PSR-295, PSS-470 | Roland: Fantom 7, JV-1000 Kurzweil: PC3-76| Hammond: SK Pro 73 | Korg: Triton LE 76, N1R, X5DR | Emu: Proteus/1 | Casio: CT-370 | Novation: Launchkey 37 MK3 | Technics: WSA1R Former: Emu Proformance Plus & Mo'Phatt, Korg Krome 61, Roland Fantom XR & JV-1010, Yamaha MX61, Behringer CAT, Kurzweil PC4 (88) Assorted electric & acoustic guitars and electric basses | Roland TD-17 KVX | Alesis SamplePad Pro | Assorted organs, accordions, other instruments Link to comment Share on other sites More sharing options...
kenheeter Posted October 7, 2023 Share Posted October 7, 2023 Your Octave simulation is very good!! Any chance you'll market it? Quote Link to comment Share on other sites More sharing options...
elif Posted October 7, 2023 Author Share Posted October 7, 2023 More about the simulation (though the details are quite hazy): The bass driver was a P15LL reconed by Gordy Kjellberg. The horn driver was one sold by Goff at the time, equiv. to an Atlas PD5A. The IRs capture the room response as well as the direct response. The IRs were captured with an HP3562A Dynamic Signal Analyzer at 65536 sps. The microphone was an MD421 spaced approx. 2-3 ft from the cabinet. The crossover was bypassed for the measurement. The crossover in the simulation is a LR4 @ 800 Hz (the stock x-over has ~ 6 dB dip @ 800 Hz) The IRs were measured at low power (3W to 5W) using a solid-state amp. The IRs were normalized as a set -- the same gain value was applied to all IRs. There was no effort to optimize the balance between drum and horn. The gain of each is as it was measured. The left and right signals for a rotor were generated corresponding to a pi/2 angular offset, equivalent to a 90 degree microphone angular separation. This could be easily changed to any pi/8 angular separation. The reasons I wanted to play with this again: To capture the IR of a stock Leslie horn driver To get a more realistic room response for a stereo presentation using a figure-8 microphone in an X/Y configuration Different "rooms" Quote Link to comment Share on other sites More sharing options...
Delaware Dave Posted October 7, 2023 Share Posted October 7, 2023 Are you planning to create an outboard pedal for this, a VST, or just do nothing? Quote 57 Hammond B3; 69 Hammond L100P; 68 Leslie 122; Kurzweil Forte7 & PC3; M-Audio Code 61; Voce V5+; Neo Vent; EV ELX112P; GSI Gemini & Burn Delaware Dave Exit93band Link to comment Share on other sites More sharing options...
jverghese Posted October 7, 2023 Share Posted October 7, 2023 Very pleasant and natural sound. Always nice to see a sim that is not 'obsessive' with the Doppler effect. Percussion sounds great, too. It would be interesting to hear how it sounds with brighter drawbar settings. Quote Link to comment Share on other sites More sharing options...
elif Posted October 7, 2023 Author Share Posted October 7, 2023 1 hour ago, Delaware Dave said: Are you planning to create an outboard pedal for this, a VST, or just do nothing? I haven't thought about it, but now that you mention it... If I do anything (rather than nothing 😉 ), I suppose a VST would be the obvious choice. Developing a commercial pedal seems a little daunting. 1 Quote Link to comment Share on other sites More sharing options...
KuruPrionz Posted October 7, 2023 Share Posted October 7, 2023 3 hours ago, elif said: The reasons I wanted to play with this again: To capture the IR of a stock Leslie horn driver To get a more realistic room response for a stereo presentation using a figure-8 microphone in an X/Y configuration Different "rooms" Consider using a small guitar amplifier to drive the speakers since you are recording at reasonable volumes. A Fender Champ (good chance you can borrow one!) or Vox AC5, all tube, 5 watts and both have small inexpensive speakers that do not showcase just how good they are. I used to gig with a Champ head plugged into an EV 12L, monster tone!!! 1 Quote It took a chunk of my life to get here and I am still not sure where "here" is. Link to comment Share on other sites More sharing options...
jverghese Posted October 7, 2023 Share Posted October 7, 2023 By the way, when you say 'Octave', are you referring to the software package that is similar to Matlab? I'm a bit surprised that 16 angular positions is enough for such an authentic sound. I assume you interpolate between adjacent pairs of IRs, in a similar fashion to what the vibrato scanner does. Great work anyhow. Quote Link to comment Share on other sites More sharing options...
elif Posted October 7, 2023 Author Share Posted October 7, 2023 55 minutes ago, jverghese said: By the way, when you say 'Octave', are you referring to the software package that is similar to Matlab? I'm a bit surprised that 16 angular positions is enough for such an authentic sound. I assume you interpolate between adjacent pairs of IRs, in a similar fashion to what the vibrato scanner does. Great work anyhow. Yes, Matlab -> Octave. Regarding the number of impulses. I was surprised too, but it's what I had to work with. A simulation I did of an A-100 chorus/vibrato, here, is what led me to try the same approach on this simulation, essentially cross-fading FIR outputs, complicated by the two different rotational velocities and the accel/decl between them. 1 Quote Link to comment Share on other sites More sharing options...
Macsaint777 Posted October 7, 2023 Share Posted October 7, 2023 Yours sounds excellent. But I would say that the Vent II version has the vent set way slower and further back than most of us would expect. 1 Quote I have gear. Don't we all? Some is old, some is new. Ask me what I've got and I'll tell you. Link to comment Share on other sites More sharing options...
Delaware Dave Posted October 7, 2023 Share Posted October 7, 2023 3 hours ago, Macsaint777 said: Yours sounds excellent. But I would say that the Vent II version has the vent set way slower and further back than most of us would expect. This.... Quote 57 Hammond B3; 69 Hammond L100P; 68 Leslie 122; Kurzweil Forte7 & PC3; M-Audio Code 61; Voce V5+; Neo Vent; EV ELX112P; GSI Gemini & Burn Delaware Dave Exit93band Link to comment Share on other sites More sharing options...
elif Posted October 8, 2023 Author Share Posted October 8, 2023 It's obviously maladjusted. It may have been recorded when I first got the Vent in 2018 (and stopped working on the simulation). Quote Link to comment Share on other sites More sharing options...
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