Shouldn’t feed such an obvious troll, but still…Running your car’s speakers at a level which causes physical pain to all of the other passengers is borderline sociopath behaviour.
Regardless of whether it’s your space; if you don’t like the possibility of a lifeguard causing a very brief pressure peak at your ears while saving someone’s life, then perhaps putting yourself in your the shoes of your passengers (I hesitate to use the word ‘friends’) would be a good idea.
Oh hell what am I saying. Have you seen the people who put floor to ceiling line arrays in their rooms? Do that. Floor to ceiling, each pass band, every driver. Go six way. Post the entire process.
Cal, you are playing right onto his hand, bad boy! He is waiting to displaying his true sense of knowledge. I am out of here. Did exactly what you did, followed etc, but could not help myself any longer and just had to respond!
Nico, good boy! 🙂
The intent was to show that going big doesn't mean going many.
I wish our friend axi had the chance to listen to properly designed big systems. The two and three way kind of big system.
So is a Hammer 😛 For me that would be a very effective way of being forced to sleep on the couch.
OK, so here are a few ideas...
Hawksford (et al, check out Esa Merilainen on www.current-drive.info as well) did research on driving speakers with current vs voltage, and I've been gathering info on that. The general knowledge has been around since at least the 80's, and probably since the 1920s (!!!) with tubes, but for a few reasons, using voltage as the controlled variable became more convenient, and it seems to have turned into -- let's say -- "tradition" in DIY. The prize is a >10dB improvement in HD and IMD by bypassing some of the unwanted impedance modulation in the speakers (unless you go to some other technology like electrostatic).
Known issues:
--Thermal runaway and coils burning up. As the VCs heat up, the amplifier compensates by maintaining a steady, audio-modulated output current. Just match the thermal ratings of the sense resistors with the speakers, so the voltage ratio doesn't change. Problem solved.
--Peaky frequency response because the gain is multiplied by the impedance. Parametric EQ, DSP, active crossovers... It's not that hard.
--Jump distortion could be a legitimate concern. (Frequency response peaks are 'tilted' sideways because of non-linear suspension behaviour that changes the resonance frequency depending on amplitude. When these frequencies are activated, there can be more than one stable working point, depending on the previous state, so the output glitches. This is fixed (if it's ever a problem) by taking the output resistance down a notch.
--Everybody either has voltage amplifiers, or they don't talk about it. It's clear to me that some of the best class-D amps actually use their "power saving" modes and on-board processing to cleverly reduce distortion. MOSFET H-bridges can be configured to produce not 2 but at least 4 unique output states: HI, LO, floating, and short. If a speaker is left 'floating' part of the time, that's one way to raise the amplifier's effective output resistance, especially for smaller signals in between the louder peaks. I'm not up to speed with the latest, but there are smart-phone audio chip-sets that measure the speaker's coil resistance to infer temperature. So there is a lot to think about from the amplifier end and how it interacts with speakers.
Assuming you're looking at "house filling sound" that you can move around in, you may want to check that the gain will be consistent for different distances and angles. Like when people mix-n-match horns or ribbons or line arrays with direct radiators. Where one decays at a slower 6dB per doubling of distance, and another decays at 12dB.
If the bass is going to shake the house anyway, why not install bass shakers (acoustic actuators?) into the walls? Seems like a lot of potential there, especially if you're building something from the ground up.
1 - not trying to build amplifiers
2 - not trying to shake the house, only myself. quite the opposite - would prefer the house NOT to shake.
3 - the point about point source and arrays decaying at different rates with distance is legitimately nightmarish. somehow i overlooked this because i started with the JBL Cinema Screen array as a starting point of the design and then simply kept improving it ...
https://jblpro.com/en-US/products/5742
the JBL Cinema Screen Array has some array-ish features but also uses a point source tweeter ...
then again i kept wondering why they use such a strange arrangement in midrange where they have two groups of two 8" midranges one running full range ( 220 hz to 1.3 khz ) and one rolled off at the top ( at 550 hz ). maybe this is actually to make it act more like a point source, or to smooth the transition from point source to array so that it isn't a sharp step at one frequency.
it's what i was saying - i knew about this stuff 20 years ago but it slipped my mind - indeed the rates at which SPL drops off with distance must either somehow be matched or the transition must be made gradual ... the JBL Cinema Screen Array threw me off because it seemed to be mixing point sources and line arrays so i simply forgot to ask myself the question whether this can even be done because they seemed to be doing it ...
but maybe they aren't actually doing it. or maybe they have taken steps to mitigate the issue with that weird thing they are doing with the quad-amped 3-way setup.
yours is the first post that made me question whether my design would actually work ...
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i think i found a solution to this particular issue ...
but combined with the other aspects i wanted to redesign i'm now so backed up it will be a while before i can hopefully re-emerge with an updated, improved design.
when you are changing several things at once you need to give yourself some space to step back and reconsider what you're doing, which means time.
I think He saw and RS Infinity somewhere consisting of eight woofers, umpteen tweeters and midranges fitted to four massive panels and boxes and goes super loud while standing about 9ft tail, and thought heck if that was a good speaker lest just follow the trend, not realizing how much time and money this development took!
That is exactly what they do yes., if you are within a day's drive of PS Audio, ask Paul to listen to their showroom reference system and ask him about the designer who is not only en ex mate (RIP) but a damn good designer. Paul has overhauled the speaker several times, and the complexity of the crossovers was noteworthy.
It would seem that you are coming to the same party, someone jolted your 20-year experience rethinking your original idea, now for that alone I commend you!
Edit: I look forward when you post your final design and see how your objective has changed
here is an update of just the effect of earplugs on the situation ( see attached graphic ).
in the previous version i was admittedly reaching to justify the SPL of the system. in my mind i knew i wanted a system that is as loud as i can build but i just couldn't get the math to work out - there was simply too much SPL. in previous version of the chart i started with 110 db because it was the highest number that could be passed off as relevant ( 1 minute NIOSH hearing damage level ) and then from there i first added crest factor and then 6db of bass boost. even after all that i couldn't quite get up to the SPL level the system was capable of.
then today in another thread when the topic of silk domes versus compression drivers came up somebody mentioned earplugs and i was like ... THATS IT ! this is the answer !
so i have re-done the chart and now instead of 110 db it starts with 100 db which is the level outdoor concerts are regulated at in some parts of the world ( A-weighted ). i calculate peak levels same as before. but i am not adding a 6db bass boost anymore, instead i now add 15 db for musicians earplugs attenuation, which is on the lower end of the scale of musicians earplugs which generally go from about 10 to 25 decibel attenuation. i show both average and peak curves both before and after being raised by that 15db.
the driver configuration has been reworked but the details are besides the point right now. the thing to note is there is more headroom at higher than lower frequencies and this is deliberate and due to several factors:
1 - higher frequencies are cheaper to reproduce than lower frequencies, and don't require gigantic enclosures.
2 - higher frequencies contain more information for the brain than lower frequencies.
3 - compression drivers have additional distortion mechanism and thus benefit from being oversized in order to lower distortion.
i should also note that Musician's earplugs do NOT provide even attenuation. they provide closer to 20 db of attenuation at around 5 khz and closer to about 10 db in the bass. the earplugs essentially provide the bass boost EQ that you would otherwise have to apply yourself, which is why i removed the 6db bass boost because with earplugs it is no longer needed. not to mention that we boost bass in music not only to hear but to feel it and obviously earplugs provide ZERO attenuation for the FEELING of bass, which is good.
in retrospect after bashing silk domes in other thread i now realize part of the reason for compression driver use in prosound is because to a certain extent prosound speakers are designed for an audience wearing musician's earplugs. even though only about 1/4 of the audience actually uses hearing protection arguably the other 3/4 are fools and do not matter. when you put the earplugs into the formula suddenly everything lines up perfectly where before nothing made sense in terms of SPLs at various frequencies.
i would have to conclude that perhaps silk domes are acceptable for home use if you don't need to feel the bass in your chest. and if you do then you should use not only compression drivers but earplugs too. because these are ultimately the two paradigms ... home / studio system without earplugs or prosound systems and earplugs.
without earplugs it is not possible to rationalize prosound system use. i was deluding myself but in the end i was right i just didn't know why. i said the answer was in my mind somewhere i just have to find it, and i did.
in the previous version i was admittedly reaching to justify the SPL of the system. in my mind i knew i wanted a system that is as loud as i can build but i just couldn't get the math to work out - there was simply too much SPL. in previous version of the chart i started with 110 db because it was the highest number that could be passed off as relevant ( 1 minute NIOSH hearing damage level ) and then from there i first added crest factor and then 6db of bass boost. even after all that i couldn't quite get up to the SPL level the system was capable of.
then today in another thread when the topic of silk domes versus compression drivers came up somebody mentioned earplugs and i was like ... THATS IT ! this is the answer !
so i have re-done the chart and now instead of 110 db it starts with 100 db which is the level outdoor concerts are regulated at in some parts of the world ( A-weighted ). i calculate peak levels same as before. but i am not adding a 6db bass boost anymore, instead i now add 15 db for musicians earplugs attenuation, which is on the lower end of the scale of musicians earplugs which generally go from about 10 to 25 decibel attenuation. i show both average and peak curves both before and after being raised by that 15db.
the driver configuration has been reworked but the details are besides the point right now. the thing to note is there is more headroom at higher than lower frequencies and this is deliberate and due to several factors:
1 - higher frequencies are cheaper to reproduce than lower frequencies, and don't require gigantic enclosures.
2 - higher frequencies contain more information for the brain than lower frequencies.
3 - compression drivers have additional distortion mechanism and thus benefit from being oversized in order to lower distortion.
i should also note that Musician's earplugs do NOT provide even attenuation. they provide closer to 20 db of attenuation at around 5 khz and closer to about 10 db in the bass. the earplugs essentially provide the bass boost EQ that you would otherwise have to apply yourself, which is why i removed the 6db bass boost because with earplugs it is no longer needed. not to mention that we boost bass in music not only to hear but to feel it and obviously earplugs provide ZERO attenuation for the FEELING of bass, which is good.
in retrospect after bashing silk domes in other thread i now realize part of the reason for compression driver use in prosound is because to a certain extent prosound speakers are designed for an audience wearing musician's earplugs. even though only about 1/4 of the audience actually uses hearing protection arguably the other 3/4 are fools and do not matter. when you put the earplugs into the formula suddenly everything lines up perfectly where before nothing made sense in terms of SPLs at various frequencies.
i would have to conclude that perhaps silk domes are acceptable for home use if you don't need to feel the bass in your chest. and if you do then you should use not only compression drivers but earplugs too. because these are ultimately the two paradigms ... home / studio system without earplugs or prosound systems and earplugs.
without earplugs it is not possible to rationalize prosound system use. i was deluding myself but in the end i was right i just didn't know why. i said the answer was in my mind somewhere i just have to find it, and i did.
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And you want to attain concert level SPL in your lounge? Sorry, had to ask. I have never listened to music with earplugs in my life. Have however used them during munitions testing in the military and on a shooting range.
Edit: would hate to run these test in my lounge just to wear my earplugs 😵
"my system is meant to be the absolute cutting edge and even be designed around DSP technology that doesn't exist yet .."
MiniDSP don't sell DSP technology that doesn't exist yet and it's certainly not cutting edge. You'll have to look elsewhere.
well like i said my criteria is i have to take an optical toslink output from TV and be able to use a remote control for volume.
you are welcome to make suggestions.
you are welcome to make suggestions.
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Any pc with a recent os can be controled through your smartphone and any pc is able to handle a soundcard with toslink or spdif input and have multiple output at the same time. Most soundcard includes mic preamp too as well as adc which will be handy for measurements ( which are going to be mandatory for a complex loudspeaker like your plan).
Any pc past Pentium3 is able to process FIR and IIR filters and eq.
Fir will induce latency so may be an issue if you want to watch real time signal video ( but there is solution to that if you can accept some limitations about ergonomy).
Iow this is one answer and from my experience the cheapest and more prone to be evolutive.
But you don't want a computer so forget this. 😉
Any pc past Pentium3 is able to process FIR and IIR filters and eq.
Fir will induce latency so may be an issue if you want to watch real time signal video ( but there is solution to that if you can accept some limitations about ergonomy).
Iow this is one answer and from my experience the cheapest and more prone to be evolutive.
But you don't want a computer so forget this. 😉
the issue with computer is what if it crashes ?
i had behringer crossover make pops worth hundreds of watts just by browsing through menus - that's why i would not use behringer - but a computer could altogether crash and send 130 decibel squeal through the speakers ... killing not just the speakers but everybody within 50 feet radius ...
i had behringer crossover make pops worth hundreds of watts just by browsing through menus - that's why i would not use behringer - but a computer could altogether crash and send 130 decibel squeal through the speakers ... killing not just the speakers but everybody within 50 feet radius ...
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