peniku8

should be fine since the horn loading isn't a high-pressure loading so it should almost behave like in free-air just take an impedance sweep, set the sine wave to the resonance and give'er should be good to go after a few minutes near Xmax and yes, it'll occur with usage, but you'll have to do a few gigs before you can set up the system properly with measurements n stuff, because calibrating the system with subs that'll be slightly different each gig doesn't make much sense

Technically, you'd use the thermocouple to set limiters and then remove it after that's done, so the simple tape approach would be sufficient. If you want something permanent, you could use thermal epoxy. As for connectors, well, I know that the NL4 MPRXX is air tight, why not use two connectors for the sub and two for the sensor?

depending on how close you are, you can bring them over to me and I'll measure them, I live in Germany but I'm right at the border to France

pm sent

I have one Skhorn

I don't have time to answer to everything, but I noticed you're looking to build an extremely light subwoofer, but the driver you're looking at has a ferrite magnet and it's almost 18kg. I'd recommend looking at something like the 18NW100, 18NBX100 or 18DS100 instead. You'll be saving 7-8kg on the driver alone and in the instance of the 18DS100 you're getting more performance (but it's 100€ more per driver). For pro audio subs I'd never go with ferrite drivers, unless weight is a non-concern (which it almost always is). That being said, 35kg is a low target. You'll need to make it from relatively thin (12mm?) BB ply and have good cross-bracing inside to keep it from flexing.

Yea you're probably better off building a new one. You've got that cnc, so should be easy

Technically, 4-6KW burst RMS sounds pretty good for high powered drivers, as long as they're not like 10dB into power compression at that point. I'm in the process of designing and building new subs and will be testing them extensively with thermal sensors and in regard to power compression. They're a bit different from the Skram/Skhorn, but use 21ds115's, so the results might be interesting here as well. On a different note, my Skhorn has been sitting in the basement unused for 2 years and I'm not sure if it'll see any use any time soon, it's a bit sad.

I'm gonna switch from clone amps to Powersoft soon. It means I can safely extract a few dB more out of my subs, thanks to the vast limiter selection Powersoft offers. Or consequently: bring less gear and ride closer to the edge of what the system can handle, without worrying that it's going to destroy itself. With non dsp amps (or amps with bad dsp) you always have to worry or overprovision your system, which gets annoying over time.

Funds and space for entirely new subs will be less than what you'd need (overall) to get additional subs to fill out the lowest octave. Looks like you're just collecting ideas at this point, since neither funds nor space for your initial proposal is available either. You can possibly replace your 8 subs with 4 Skrams and get the same midbass output, plus better sub bass, but you will likely need new amps as well. Well, to use them to their full potential at least. 3-5KW per Skram should be a good match with TotL drivers (burst; they will melt if you give them 5KW sustained averages).

I can just echo the others here. Once you get proper subs to supply the bottom end you're looking for, these cabs will also be able to replace your current subs. And if I was space limited, bass horns would be the last thing I'd load into my truck. IPALs it would get, in tiny vented cabs.

By the time you have enough Othorns to keep up with the midbass of the other horns, you can get rid of the USBv2s entirely. Beisdes that, the Othorn isn't an infra design, they will probably not add as much as you'd hope for. If you want infras, you might want to look into a custom vented cab tuned to ~20Hz or so, but you will need a lot of juice (and a lot of cabs). And then ask yourself, do you even need them?

Wow that's hardcore, I bought my last 21ds115's for 380€ (600AUD), but they're up to 640€/1000AUD now, which is a price I'm sure you'd be very happy about still. It's crazy how bad it is when you don't have an official distributor on your continent.

Where can I find measurements of these subs? They seem to be as big as a double 18 while only having one driver, looks pretty oldschool to me when amps didn't have the power on tap than they have today.

What would the sonic differences be, if both amps produce the same frequency response and produce less distortion than the speakers do (which they do, unless they're defective OR clipping)? If this listening test was a DBT with perfectly matched gains (with a voltage meter) and ONLY the amps were swapped (ideally via switch in rapid succession), then the comparison is fair, but as soon as it involves sighted bias or any other uncontrolled variables the test is invalid.

Did you measure anything at all or is that all just guesswork?

No worries, I figured Happy new year!

No, the RF is over 15" deep and it would require significant effort to mount it like this, it's not meant for that.

I can only second this, you were doing god's work here, much appreciated. Would be neat if there was a way to archive everything and make it accessible, since theres tons of valuable information on here. I've been thinking about something like this for a while, just not in this context, but how about moving data-bass/those who are interested over to Discord? I'm member of two other audio-related Discord servers and the information throughput and value in the discussion is through the roof! The instant-messanger style combined with forum architecture is super cool imo. We could make a new server with live sound&cinema sound based topics. Any thoughts?

Based on the TH118's spec sheet I'd guess it's giving up some low end (its F4 is at 37Hz) for a bit of added sensitivity at higher frequencies, which might mean that in its passband, the TH118 would be able to keep up with the Skram, but below 40Hz the Skram will outrun it pretty quickly. I didn't look at cab volumes and the best data point would be CEA2010 ratings for both made by the same person, so take this with a grain of salt. Any horn-kind of design doesn't lend itself well to going deep while being space-efficient, I feel. The Skram is a hybrid, which kinda gives it the best of both worlds.

I think the Powersoft X8 is the only amp I know that delivers the power you're asking for in a small space with more acceptable fan noise than those clone amps produce. It's by no means quiet, but the fans ramp up and down very quickly and in the video I've seen the amp didn't seem super annoying at idle. The X8 does 8x1600W into 8R in 2U, but will also drive 2R and below. You'll get SOTA processing and features, but also a SOTA price tag.

Did you add baffle gain calculated in Edge to the hornresp prediction? In my last project I got the predicted response to be within 1dB of the actual half-space response, but I had to double the baffle size in Edge (maybe that's the effect of the half-space loading: it mirrors the baffle on the ground basically), hence way more upper bass than hornresp predicted. I'm not sure how this translates to larger cabs, but it was spot on with my single 21", a tad smaller than the Skram. Hornresp was also fed with the set of complex inductance parameters. I used the specs for the 21ds115 you measured. Same thing applied to my 1x12" sub. Model response was spot on with the measurement.

By "lack of cone control", do you mean non linearity in the translation from electrical to kinetic energy or do you mean cone flex? The former can be remedied by a stronger motor, the latter through a stiffer cone. Both problems are challenges to the designer, not to the end user. Any properly designed driver will play predictably based on the Klippel graphs. For B&C drivers I think it's the Xvar value, which is a general rule of thumb for when the driver behaviour will transition into non-linear territory. If this was a huge issue, big drivers wouldn't be so popular.

Did you do those tests yourself? How was the M-Drive set up, did it have an additional heatsink/ventilation or just the module by itself with its two small fans?

The 3000pfc's datasheet states 4000W of total (symmetrical?) power output, which would underpower 2 drivers, let alone 4. If you wanna use 2 21ds115's to the maximum of their capabilities you will need pretty much twice as much as the Digimods are capable of. I ran my FP13000 unlimited&bridged into the Skhorn (4R) no issues (music, not sine waves). That's a bit overkill, but I'm trying to run 4 drivers off one amp, which the M-Drive seems to be a good match for.