no prosound background. i just believe that prosound is the only objective field in audio.
i believe that both home and car audio is 99% products designed for people who do not understand what they're buying and literally make purchasing decisions based on the color of speaker cones, cabinet finish, the thickness of the amplifier bezel, the size of the volume knob and so on ... i just can't take any of it seriously anymore.
you look at prosound - 100% of all the cones are made out of paper. you look at home audio and its anything but paper - every color of the rainbow and every material is represented in speaker cones - everybody says their cone material is the best one - but then the same companies also make prosound speakers and they have paper cones and 10 times the performance ... it's almost like it's all just for marketing to people who don't know any better 🙂
same for cabinet shapes. prosound - every single cabinet is a plywood box. home audio ? you name it ...
it is all so tiresome LOL.
i simply respect prosound because it is real and true not some fake BS like home and car audio.
i do not believe that home audio represents a different set of design problems. i believe it represents a different set of marketing problems. in pro audio products are marketed to people who have a clue. in home and car audio they are marketed to people who do not. that's the main and pretty much only difference.
of course there are other differences but i have completely switched to only pro audio equipment and speakers about 15 years ago and at this point i am physically unable to look at home or car audio equipment or speakers without laughing.
it's like if you went to a children's playground and some children offered you to play with their toys - you would have to appreciate the offer but at the same time you could only laugh at the suggestion. that's all home and car audio is to me - children's toys. can't see it any other way. they're even made in the same colors as children's toys and it is NOT a coincidence ...
i know i will regret saying these things once i had some sleep ... i apologize in advance for how i will feel about it tomorrow.
what's amazing though is some of these toys cost more than the real thing ...
imagine if toy cars cost more than real cars ?
we actually have that in High-End Home Audio ...
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Without about 5 or 6 asterisks attached to each of these statements, they're laughably incorrect.
As you say, the rest of it is incoherent.
Someone involved with pro would know that 500Hz to 2kHz is 3, not 2 octaves, underscoring the fallacy of his premise that 5 or 6 ways are needed. Afaik all big stacks are three ways in the frequency domain. Timewise, there might be other ways of course in order to impact directivity.
As soon as you go beyond a 3 way, drivers that are separated by a band will impact each other. This creates a hopeless directivity mess.
The exiperiodic driver was made to have a horn go from 400Hz to 20k so that you can have high SPL with a two way. Every crossover point you add creates exponential trouble.
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I disagree with every word of your post.
Axiperiodic makes some very good points, asks astute questions and makes sense. You on the other hand...
Big line arrays tend to be, but there are many small to medium (very large by domestic standards) that are 2-way or 2.5 way. They are, of course, meant to be run with subwoofers.
It is true about covid and brain fog, unfortunately.
It also made me start posting again. You are so right. But I stand behind the point I am trying to make. Anything beyond a three way is a travesty waiting for trouble to happen.
Ouch !! Get well soon !
While more ways can mean less IMD it definitely means more trouble (and more frustration) impementing it properly.
Regards
Charles
While more ways can mean less IMD it definitely means more trouble (and more frustration) impementing it properly.
Regards
Charles
Sorry to hear. ...do get better 🙂
The most remarkable gain in SQ i've made in a half dozen years working with sometime 2&3ways, but predominantly 4-ways.....was to take it to 5-ways.
Yes, it takes know-how to avoid integration train wrecks ...but the principles that apply to a 3-way, simply extend out. It's become quite easy really...
In my case for home use, it has been the further integration of the acoustic centre of the different drivers that has made the largest contribution to SQ. More specifically to the coherence, resolution and imaging this offers. As a next step on this journey, I am trying to get some prototypes ready using concentric drivers of different sizes. A big horn with low cut off does pretty much the same.
The more plenty ways you have, the even more impossible this alignment of acoustic centres becomes.
The more plenty ways you have, the even more impossible this alignment of acoustic centres becomes.
very much agree with that goal....acoustic priorities come first....and that acoustic center integration has been #1 goal.
For most designs, i agree. For MEH's i think it gets easier, when the way they work starts making sense.
A point source isn't necessarily the be-all, end-all means to the "best" reproduction of music. Otherwise, why would anyone be happy with a line array?
Having said that, I think a multi-way speaker with minimal driver spacing in overlapping passbands is an excellent archetype.
Depends on how low the coaxial can run. The "better" ones tend to have the woofer significantly limited in Xmax capability due to a) suspension bottoming out and/or b) modulation of the tweeter output. Because of this, you might not be able to achieve c-c < 1/4 wavelength at crossover frequency.
See: KEF, Genelec
See: KEF, Genelec
Thank you brother !
To me this was obvious from day one. My very first speaker as a teenager in High School ~ 25 years ago was a 3-way with 2" Morel dome midrange and 19 mm Hiquphon tweeter crossed at 3 khz. Those two worked like magic as a team, unfortunately the woofer section i screwed up. In retrospect i know it should have been a 4-way. The woofer i had in there ( 10" Yellow Kevlar Focal in a sealed box ) was good for probably about 100 hz to 400 hz or so but i had it from 650 hz all the way down ... I should have used a 8" midrange in there down to 150 hz and a pair of active 12" woofers in vented cabinets.
of course back then to even use a dome midrange was already a sort of an act of defiance as you can imagine everybody online was trying to persuade me to do something like a 2-way with 6" midbass and 1" tweeter and i ignored their advice and just did it my own way. if i listened to them i would likely have a speaker with roughly same performance but cheaper to make ... but it would have been a complete waste in other ways ... namely it would be generic.
even though my grandma ultimately ruined my speaker by putting some potted plant on it and over-watering it - i got a good run out of them. i had more than enough time to not just show it off to all my friends but to get stoned with all of them and listen to music together on those speakers. no one has ever doubted that i had built that speaker myself because of how unusual it was and just the fact that it was made out of unifinished MDF on all sides except for plywood baffle ... and it was a source of great pride for me that it was so unusual and still worked even though everybody said that it wouldn't.
my main issue with that speaker was that i knew of SPL limitations of a 19mm silk dome tweeter and was always reluctant to turn them up. at one point i had these speakers running off of QSC PLX 2402 amp which was certainly capable of frying those tweeters. so for my next trick i did a car audio system that was 5-way, with a 1.5" scan speak dome mid-tweeter and a Beyma AST05 Bullet Supertweeter crossed at 7 khz ... i also had 5" Beymas in front doors and 8" Beymas in rear panel and i had two 15" RCF subs purchased but never installed them because the car died ... at that point i had a job so i just junked the car and leased a BMW with a Harman Kardon system already in it ...
as you can see that system was already entirely out of prosound drivers except for the 1.5" scan-speak mid-tweeter dome ( which was excellent ) ... all my friends complained that the system was too loud ... of course i was using Etymotic earplugs and they weren't. but it wasn't hypocritical because i also used hearing protection everywhere else as well ( like on NYC subway, which makes extremely loud screeching and squealing noises ) and they weren't ...
that car audio system was a huge upgrade from the previous 3-ways. the main difference was i was never in fear of blowing it up by turning it up to ear-bleeding levels ... well, except when i was listening to it from outside the car ...
for my home needs after my grandma killed my speakers i just went to commercial 2-way Studio Monitors + DIY subwoofer ( TC Sounds LMS ). As i was based out of a small NYC room with cinder block walls and concrete floor and ceiling it was enough output because my listening distance was about 3 - 4 feet and the room had a lot of gain at very lowest frequencies ... i could hear the sealed subwoofer in that room to about 22 hz. my neighbor could hear it too and called every day.
but people kept escaping NYC ... one of my best friends went back to his home country and another went to Florida ... it was time for me to leave NYC as well, but i didn't want to over-do it so i just moved to New Jersey about 50 miles from NYC.
That said 50 miles is a lot when you're moving out of NYC - the room situation changes radically. suddenly your walls go from cinder block to drywall. your floor from concrete to oriented stand board. your ceiling from concrete to drywall. the volume of the listening space went up by about a factor of 4 and all the surfaces comprising this volume are now about 10 times more acoustically leaky and instead of having 3 neighbors behind the wall, the floor and the ceiling i now have zero.
well there is still a neighbor in the house that is 11 feet away from mine and he WILL hear the bass ... but at least it will be his living room. the houses are mirror image of each other so the wall where the speakers will be, which is an exterior wall, is 11 feet away from his wall which is also an exterior living room wall. it is a much smaller problem than sharing a wall with my neighbor in NYC and it was his BEDROOM and i was blasting industrial music at 2AM at night on the TC Sounds LMS subwoofer when my stoned friends would show up.
I honestly feel bad for my NYC neighbor - and i already feel bad in advance for my new neighbor as well but it won't be his bedroom, there is an 11 foot air gap between the houses and this particular neighbor is in Florida or something like that half a year anyway. I don't talk to them but they seem to be away a lot of the time. the way these houses are laid out is actually all his bedrooms will be quite far away.
it is still not an ideal situation and i would still have to turn it down at night ... but it's enough of a change that it warrants a full redesign of the setup from the ground up, and this setup will NOT change until i move again, which might be NEVER.
there is no sense in doing incremental upgrades within the same space. i want to design a system to be loud enough to fill the relatively large space effortlessly but also compact enough that it could survive a move back to NYC and i want the system to be upgradeable through just a change of DSP processing without having to build new cabinets.
i mean most of the change in technology in the next 10-20 years will be in DSP so the plan is to build a system that already today anticipates DSP capabilities that are not yet commercially available. the system can then be upgraded in the future just by swapping for a more powerful DSP.
i will not be doing any measurements building the system but the fully-active design that exposes the electrical connections directly to each of the individual drivers will allow the system to get measured in the future and for DSP to be re-calibrated accordingly.
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NO ...
home audio was traditionally limited by silk dome tweeters on one end and passively cooled linear amplifiers on the other
a system had to be designed within the limitations of a 90 db / watt tweeter with ~ 20W power handling and an amplifier capable of maybe 200W peaks.
it made sense but then class D amps hit the scene and suddenly you could buy a Behringer amp with thousands of watts of power and at that point you had to ask yourself ... does it make sense to cling to that silk dome tweeter when all it does is bottleneck my system ?
the first thing i did was go from 19mm fabric dome tweeter to 38mm fabric dome mid-tweeter with a bullet supertweeter on top ... that doubled the system output but also doubled the number of frequency bands to cover the highs ... it was definitely worth it ... but now it's time to take the next step ... except i don't believe in incremental upgrades so i will take ALL the steps at once ... i want to take steps as far as i can see and further straight into the abyss because YOLO
there is a certain hierarchy of drivers that looks like this:
dual diaphragm annular compression > annular compression > dome compression > dome > cone with large diameter VC > cone with small diameter VC
it is basically just a ratio of voice coil diameter to driver surface area. because the cost of the driver is almost entirely in the magnetic gap. it costs nothing to make paper cones or stamped steel baskets.
the cheapest systems consist of a single cone driver with a voice coil of about 20 millimeters. as performance increases so does the number of frequency bands, the woofer voice coil grows to maybe about 32 mm and a dome appears at the most difficult to reproduce frequency band, that is the tweeter ...
as the performance continues to increase the driver types begin to move down in frequency and voice coil diameters continue to increase, so the dome gives way to a dome compression driver and woofer VC diameter grows to maybe 2.5 inches.
as performance increases further we now get a midrange driver that is horn loaded and the tweeter goes to an annular ring. woofer voice coil is now 3" or more.
at some point the only way to further increase performance is to use arrays. this of course is tricky and best left to professionals. but if i can identify the most critical audio band and avoid arrays in just that one band then i can accept some irregularities in other frequency bands resulting from the use of arrays. this would be the point IMO at which i strike the balance between SPL and sound quality.
as for your 95 db average / 110 db peaks at listening position ... well it isn't bad. i mean apparently concerts are now regulated such that average A-weighted SPL has to be not more than 100 db, and they do put it right at about 99 db to meet that regulation. but this is A-weighted which means it can be about 10 - 15 db more in the bass.
a 90 db/watt tweeter would need 10 watts of input to hit 100 db @ 1 meter. it would need 40 watts to hit 100 db @ 2 meters. that's about the power rating of these tweeters. now this may be "enough" but you're at the limit. you will have to be sitting there with an SPL meter to make sure you don't accidentally k1ll those tweeters. as i said i never k1lled my 19mm dome tweeters but the thought was always in the back of my mind that it might happen.
haha i explained it so well i am even beginning to understand it myself now, thanks !
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1 - funny you mention that because that's where i want to go as well - sideways - create more amplification / DSP channels but not more frequency bands, in order to control directivity ... just as it is done in big sound reinforcement rigs and even in some more reasonably sized systems like the biggest JBL Cinema Screen Array model that splits the midrange into two channels to control vertical directivity while keeping the overall 220 hz to 1.3 khz frequency band. in fact this is what the traditional 2.5 way systems do as well, though they may mostly do it for baffle step compensation.
2 - well that depends on crossover order slopes. certainly i agree that if your crossover regions are wider than your frequency bands it will be a nightmare. as the frequency bands get narrower so must the crossover regions get narrower too. i plan to do 5 frequency bands with 48db/oct crossovers. four crossovers at 48db/oct each will together be as wide as one crossover at 12db/oct which is what a typical hi-fi speaker has.
3 - the axiperiodic tweeter was one man's PHD thesis turned into a commercial product, which is incredibly impressive but completely useless. i will NOT be using it myself. in his own presentation where he explains how he used used computer modeling to design the axiperiodic tweeter he admits that above 3 khz or so the distortion is entirely due to the horn and there is nothing his driver can do to overcome it. to reduce distortion above 3 khz the horn flare rate would have to increase but then the horn would lose the low frequency extension. in other words you can design a driver that covers 300 hz to 20 khz but you can't get it to play that range on any given horn. this makes the driver a complete waste and simply an academic exercise good for a PHD thesis and an interesting YouTube lecture but not usable in a real world application.
basically in all drivers at low frequencies distortion rises due to increasing excursion multiplied by the nonlinearity of motor and suspension ...
at high frequencies in all drivers distortion can potentially ( but doesn't have to ) rise due to cone flex and breakup ...
in compression drivers there is an additional distortion mechanism though in that the air cavity getting compressed is inherently asymmetrical and nonlinear, in fact it is exponential ...
no other type of driver has asymmetrically exponential relationship between excursion and SPL and therefore no other driver type has such horrific distortion ...
this distortion can only be mitigated by reducing the amount of compression used which can only be accomplished in 2 ways - increasing driver area and increasing rate of expansion of the horn ...
well there is a third way as well - you can reduce the bandwidth over which the driver is used because this kind of distortion rises with frequency ... basically if i understand what is going on is that horn loading increases with frequency such that at low frequencies horns present little loading and therefore not much pressure and not much distortion while at hither frequencies this distortion can reach 50% or higher ...
because horns have a sort of an exponential flare to them they will have a relatively narrow band of frequencies with optimum loading - below that band distortion will rise because displacement is not controlled - and above that band distortion will rise because loading is too high and compression too high resulting in distortion from the air cavity itself even if the driver remains clean ...
i only learned this a few weeks ago after being an audiophile my whole life but it was this recent project that forced me to start reading again ...
my design is sort of out-pacing my own understanding of what i'm doing. i am understanding it in the process of explaining it to you people. it's kind of like in sports science the best athletes are always ahead of science and science attempts to understand how they do it. it's kind of like a hallucination based on things i have already read but haven't yet understood and i'm trying to understand them in the process of debating.
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