BillFitzmaurice.info

I think it would be most effective when i'm on the point to test limits that i will do the signal chain from start to beginning, list it here to show and in case to be let it correct.

Two Points from your posts:

The amp has a "security feature"; it locks the output to zero if it hasn't any speaker connected (no resistance). Probably to avoid having some short circuits out there in case of material failure. I'll see how i can measure the resulting voltage in the output; maybe i will have to measure with a resistor to show the amp some counterpart that it cooperates and calculate with that. Will see what my multimeter has to offer.

The other point about different kind of limiters:
Yeah, there is a bunch of different types of limiters. Treshold, knee, ratio, release; the limiter and the compresser work very similar (in the audio chain).
In the end, all limiters give a limited voltage output as a result yes. Brickwall has a lot of optional values to zero, in the audio chain.
But VPL should be the most brickwall thing as it can be, as there are no points like treshold and release; if i get that right it just cuts the voltage above a given value.

In addition, i think i had a language barrier about current and voltage. But i looked again; VOltage is what i meant by current yes; measured in Volt. Current as measured in Ampere; a result of the given Voltage against a specific resistance. So yeah, two different things. But i meant voltage, just mis-translated bc the word seemed right - but wasn't.

But lets keep that for later, i will show the whole processing chain once i am done with the cabs and then everybody is welcome to show me where the errors are. I'd be glad to get corrected.

Marflinger wrote: ↑Thu Apr 16, 2026 8:58 pm i think i had a language barrier...

I don't know if you're typing this all out directly from your head or using a translation app/program. But, since you joined the forum, as written, your English is superb and your communication skills are excellent. Some of them so good, I thought to myself "this HAS to be an AI generated communication".

In any case, I was pretty certain it was a simple word mix up.

Do let us know when it comes time to set the limiters. Happy to walk you through it.

For a dummy load, pretty sure you can just wire up a toaster, cloths iron, or maybe even a soldering iron to fool the amp. No need to buy anything special. Guessing toasters/toaster ovens there are roughly 50Ω, give or take. Wonder if that would do it ,or if you'd have wire up your neighbors toasters in parallel too.

Seth wrote: ↑Thu Apr 16, 2026 10:08 pm "this HAS to be an AI generated communication".

Hrhr well thank you for the flowers. but no, no translator used (and no AI as i stay far away from that); this is just off my head and this brings errors like that.
Glad we could resolve that error, more to come :)
I do a lot in english, visiting UK as well fromt ime to time...so i am somewhat experienced in this language, and sometimes fool ppl to be a native speaker :P But i am not, not at all.
According to the brits, my spoken accent sounds like something to the manchester area or western coast around there :D funny conversations every time.

Seth wrote: ↑Thu Apr 16, 2026 10:08 pm No need to buy anything special.

I think my multimeter already has the option to give a resistance, will try around with this and see what happens. Not unsolveable, i will do the process public here when i reach this.

First the cabs now; did add a few handles when trying around how to lift them the best, having the additional driver weight in my mind. The cabs are infact quite big...
The weather comes together slowly, i hope i can show the result soon of the first pair painted. As soon as the go out of the shop for the paint, i can start the next pair inside.

:) finally coated Edit:
these were sprayed, which works somewhat different to rolling.
Had to thin it a lot, coverage still good.
I tried a few things to get the structur from spraying, but that didn't work out for me. I rolled through the last layer, result is fine now. Maybe i'll sand the next to a finer grit, try around a bit. These were 60/80 sanded, next maybe additional 100/120.

Oh, and i used nearly 2 cans of duratex for these two, so i think it'll take 7 cans for all 8. Will stock up to be covered, i thought it'd be less.

While the duratex sets i'll finish the wiring, and then testrun the pair just bc i want to :) well, i just have to :)

Next edit:
Thinking about wheelboard-v-plates...
The 4 cab dolly will maybe be a bit to much to handle. This would be super massive in terms of dimensions and also weight.
Maybe wheels on the cab itself is the better way, thought about 4 wheels on every second cab and strap one without wheels to each wheeled on top to have dollys of 2 cabs. Way better to handle, thinking about pushing 4 does just not feel right.

Would i need some sort of load spreading when attaching the wheels to the back? Or just close to the corner without an additional panel? Not sure about the somewhat thin 12mm...
On the other hand, the corners all have the corner panel inside, should be stiff enough for the weight of 2 cabs?

oooh boy-Beasty.
Did set up one dr and the two t30.
Set the vpl to 100v to be on the safe side, but didnt reach that far.
I have very few neighbours, but there was one around a km away that stopped the experiment bc he had too much vibrations :D This was the setup for now :D
A quarter of the rig to be, running way below its limits, is already quite impressive :)
The full stack will be super overkill :D i already love it :)
Did the one wheeled one backpacking, i think it will be enough wood to carry two.
Did the side covers, soldered the drivers, connectors to come (waiting for the correct size cableshoe, found one)
Tried a few ways of sealing tape, the shown works best.
Flanges cant be wide enough, i'd recommend doing them as wide as possible to still fit the driver.
airtight everywhere, had to fix everything around me to be sure none of the rattling was from the cabs :D
The tape
The tape, but covered :)
The drivers wired
Protect the baffle when soldering there
Paint went all the way in :) nice benefit from spraying
Aaand the wheels including the loosly wired testing cable :)

Will measure, but will have to drive far away for this :D

That's awesome! Congrats on that little taste of completion. Everything's looking really good. Square, concentric, and uniform. Well done!

Out of curiosity, what were the first two songs you played?

Marflinger wrote: ↑Sat Apr 18, 2026 7:52 am Set the vpl to 100v to be on the safe side...

This was the right move. The difference in output between 100V and 107.5V is completely imperceivable at only 0.6dB.

Thank you :)

Seth wrote: ↑Sat Apr 18, 2026 10:34 am what were the first two songs you played?

:D
Interesting question.
The first was some of my own, i do some sort of music, but not online available

The second one: https://m.youtube.com/watch?v=us3jW52AgAY

The third: https://m.youtube.com/watch?v=KmCsgcn_iKU

Based on the moment that i wanted to hear the t30 the selection came up, but quite random.

i sat for a while after i had to turn it down and listened to a lot more on a roomlike level, but sounds fine in every way.
So i sat there and just enjoyed :)

So far so happy :)

Seth wrote: ↑Sat Apr 18, 2026 11:59 am

Marflinger wrote: ↑Sat Apr 18, 2026 7:52 am Set the vpl to 100v to be on the safe side...

This was the right move. The difference in output between 100V and 107.5V is completely imperceivable at only 0.6dB.

I didn't reach that anyway...and when i see what two cabs do, i probably don't want to reach the limits with 8, at least not when i am standing too close to it :D

When completed, i'll drive to a place where i can fire things up, will measure everything and tune that beasts to my will :)
For now just slightly corrected the dr, the t30 just hp/lp

Marflinger wrote: ↑Sat Apr 18, 2026 12:32 pm I didn't reach that anyway...and when i see what two cabs do, i probably don't want to reach the limits with 8, at least not when i am standing too close to it

When completed, i'll drive to a place where i can fire things up, will measure everything and tune that beasts to my will
For now just slightly corrected the dr, the t30 just hp/lp

Once you get the T30's EQ'd and playing true 30-35Hz content to a larger group, my guess is you'll be bumping up against the limiter more than you might think... even with 8 cabs.

One... because the EQ it takes to achieve a satisfying bottom end will just naturally result in more voltage at the bottom.
And, two... because it'll sound so good you probably won't be able to resist! It's gonna sound great! I'm excited for you.

I really liked the third song you played, "Hypnogogia". Added it to my Psytrance playlist. Thanks!

Seth wrote: ↑Sat Apr 18, 2026 6:06 pm third song you played, "Hypnogogia". Added it to my Psytrance playlist. Thanks!

For your pleasure:
https://drive.google.com/file/d/1RjPjAl ... p=drivesdk
:)

For me this sits in the glitch-section, also somewhat diffuse borders there...
Mr bill and electrocado and so on, wild variety what they have as ouput.
Psytrance (for me) rather this direction: https://m.youtube.com/watch?v=2z4UDDG5gao or crazy astronaut/furious...but everyone to its own pleasure :)

Seth wrote: ↑Sat Apr 18, 2026 6:06 pm you'll be bumping up against the limiter more than you might think... even with 8 cabs.

Iirc, there was this stepped response in the simulation of the cab, with a 5db rise or so around 50hz. Maybe i'll use that, and instead of pushing the lower part upwards just lower the upper as there will be a lot of backup power...but we will see :)
Right now with only a pair the highpass was at ?32hz, when complete i will carefully try how low i can go :)

Two additions, going through the pictures i took: Instead of corners i go for these mats, to avoid any gaps when stacked. I'll think about something similar for the vertical edge to have it shut and sealed.
Here only for the top-plate, when stacking also one in the back for sure.

And i had a shot from a sweep i did, but levels were faulty, so i aborted this and went over to music first...but just for the curious minds: The forementioned step visible, pretty close to sim i think. Good to know that was not that far off :)


And adfitional:
The two cab dolly is good to go, wheelable terrain is fine even with little obstacles to handle alone. Did flip the top cab to have the top in the bottom to lower the center of mass closer to the ground.
To the lifting in general: i can handle single cab alone, also the stacking. But rather on the top end of what i am willing to handle, and i am kind of fit and trained.
So for not that fit people, the double cab may be a bit too much.
If i would run this on a daily basis, i'd go for single as well. for my usecase fine, but i'd think about that carefully (for the fellow reading this before building double)
One is around 60kg now i'd guess, will put one one a scale


I know this doesn't tell anything, but the linked reference for psytrance above playing here, recorded by the (hq) mic of my phone:
https://drive.google.com/file/d/1zzumjv ... p=drivesdk

Was that trace taken with the highpass filter disabled?

If not, what frequency and slope are you using for the T30's highpass?

Seth wrote: ↑Sat Apr 18, 2026 10:33 pm Was that trace taken with the highpass filter disabled?

If not, what frequency and slope are you using for the T30's highpass?

It was, just out of curiosity.

(As i said, levels totally off. Ignore the db number, just the graph)

iirc i set a bw 12db/oct at around 32 or 35 hz; will see if a lr will do something better.
The phase will be interesting when running alltogether.

Without having access to the Hornresp files, I'd highly recommend using the frequencies and slopes in the plans.

But, you have aparantly modeled it fairly close in Hornresp. If you haven't seen it in there, you can apply filters then check that the excursion is under control at your planned max voltage. If you have already run those Sims and chosen your freq and slope based on it... I applaud you.

In any case, well done.

Seth wrote: ↑Sat Apr 18, 2026 10:48 pm If you have already run those Sims and chosen your freq and slope based on it... I applaud you.

Nothing to applaud, i just wanted some protection before letting music run through it, nothing simulated and no further thoughts.
I will do this when really running everything out loud.

Edit:
Just took a look in the plan: There is no slope recommended, just 35Hz when less then 4 Cabs, 30Hz when 4 or more.
But i think 12db/oct takes it down fast enough...will simulate in hornresp as it seems to be somewhat close to reality and go from there.