Two different things. One is actual noise, the other is resolution. If you make an active crossover with op amps you need a power supply. Those introduce noise and doing so well, with low inter-channel crosstalk is a challenge you don't have with passive. Add in extra stages for EQ. Not insurmountable challenges, just new ones.
The issue with ADC converters is the resolution and where in the chain they are. For instance, if it's after a pre-amp, the 16 or 24 bits of ADC resolution is going to be limited to less than full range. As far as I know, in terms of noise, even entry level stuff is pretty low noise.
For instance, at normal listening your preamp may be sending out say 0.1 V to get around 1 Watt (about 2.5 volts, a little shy of 1 W with normal 28 db of voltage gain)of Amp output. Doing some quick calculations though says it's not that bad. For an ADC expecting 2V for full-range at 24 bit, that's about 19 bits. Not terrible.
On the other hand, if the crossover is being fed by the digital output of a streamer / PC / CD player (remember those?) then it can use all 16 or 24 bits of resolution for the math. How much is audible is another issue though. My hunch is not much. Plus this way you can use banks of DAC's!
I'd love to have 5 Audio Research DAC 8's driving my 5 2 way home theater monitors. Pretty awesome indeed, but I'd be homeless. I use and have used some pro dsp hardware available on the market in EU. As soon as you get a little serious (the middle range in either Dbx,Xilica,Dolby,...), ADC and DAC are goods to very goods on this pro units! You can have the possibility to sync to wordclock, multiple inputs and outputs, real time operation, sometimes a practical gui for relatively cheap, and on some units dsp and algorythms are quite good!
Yum. But I think Dolby is crap. No one there cares about noise or performance, just tricks. Anyone else I'd consider.
If you can't afford a pro hardware unit, there's some lovely solution using Pc: there's a relatively wide offer of software (from the mastering grade to more affordable-even ASIO plug ins) and small (read relatively cheap) but good quality multiple inputs/outputs soundcards are widely availlable second hand.
If you use only digital source you can have everything in a small package (player and treatments), it can even be noiseless.
And do other things too.
I like it!
Best,
Erik
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I haven't read the whole thread!! (Because it does take time billshruv.....) So I am not sure if IMD in the power amps (when active) has been mentioned.
If your bandwidth is say 30 to 15,000 the ratio of frequencies is 500:1 for the amp in a passive Xover setup.
Every time you split that you do make serious reductions in what you are asking your power amps to do. I.e. active crossovers at 400 and 3,000c/s then give ratios of about 13:1, <8:1 and 5:1 for your three amps.....
I recall back in the '70's and '80's some of the projects in HFN/RR (UK) reported unexpected improvements in clarity from active setups that surprised the builders.
It may be like that for people who are sensitive to IM in amps.
I have a first edition of Martin Colloms loudspeaker book from 1978 and when looking at active speakers I think he places reduction in IMD in the amps as the very first benefit......
Cheers, Jonathan
If your bandwidth is say 30 to 15,000 the ratio of frequencies is 500:1 for the amp in a passive Xover setup.
Every time you split that you do make serious reductions in what you are asking your power amps to do. I.e. active crossovers at 400 and 3,000c/s then give ratios of about 13:1, <8:1 and 5:1 for your three amps.....
I recall back in the '70's and '80's some of the projects in HFN/RR (UK) reported unexpected improvements in clarity from active setups that surprised the builders.
It may be like that for people who are sensitive to IM in amps.
I have a first edition of Martin Colloms loudspeaker book from 1978 and when looking at active speakers I think he places reduction in IMD in the amps as the very first benefit......
Cheers, Jonathan
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The plate amp was just an example, but a hybrid approach would not be terrible. He could do active between the woofer and midrange, passive above, and gain the EQ benefits of the plate amp. An interesting compromise. Also, he could use the plate amp to delay the mid/tweeter section eliminating at least one of the timing delays.
Also, the check you wrote for your attitude and demands bounced. I'm here to enjoy myself, and help when I can, not meet your expectations of how much time and effort I spend on it. If you were expecting the privileged role of being my employer for any amount of time please resubmit your request on the back of a stack of $100 US bills to be considered.
Best,
Erik
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Ok. We are talking about different thing so. My set up is fully digital: Pc with RME aes card to filter dsp (Dolby (
!) Lake LP4D12) to pad to amp. I don't have an active stage in the signal path to drivers except the amp by itself and the Lake DACs. It may change at one time or another (i could use differential to unbalanced buffer active stage for the bass amp which is... unbalanced!) but i'll keep a passive attenuator volume control(Amb Delta 1 passive discret stepped attenuator: relay and resistor that's all).There is no noise, nada,zero. Full dead black background. And i can guarantee you the Lake is not crap at all... By far the best processor i've ever owned, with incredible hardware capability (192/24 bit for real, syncable) and probably the best FIR algo you could find on a processor. Once clocked via wordclock (this is the only part which could have been upgraded by Dolby at the time but it's not a clock generator!) it's even better than stock. As good as i use 2 inputs and 2 outpouts from the unit to my dedicated mastering chain when i do one sometimes.
That's one of the reasons i switched definitively to multi amp active filtering. One other quality i find nobody's talking about is the consistency of character versus volume: global sound don't change between low level and large level, it keeps the same character. When you had some very nice speakers which are very nice just when you hit them at 95dbspl rms this is a real heartbreaker.
I'm glad Dolby is making better stuff than I remember then. In the 80's their theater processors were noisy monstrosities.
In terms of low level listening, and I may be alone here, I find the quality of tweeter capacitors makes the biggest difference. It doesn't take much either. Inexpensive Mundorf MKP's will add lots of detail and air that the majority of OEM caps lack.
Best,
Erik
In terms of low level listening, and I may be alone here, I find the quality of tweeter capacitors makes the biggest difference. It doesn't take much either. Inexpensive Mundorf MKP's will add lots of detail and air that the majority of OEM caps lack.
Best,
Erik
You can enjoy yourself without being lazy. You spend a lot of time starting posts and typing. Surely spending a little bit of time reading a thread before posting is not too hard, even for someone who is going for 'troll of the year' (your words).
But its a free forum, so if you want to just be a noise source I cannot stop you. As you cannot stop me from commenting on it. Freedom is good like that.
42 posts does not take long to read. but no it wasn't covered specifically
Not specifically but I think Doug Self mentioned reduced IM distortion as an 'illusory' advantage of active xovers in the lecture you linked to.
PS: I did read the full thread but I only just now noticed your link to Troels site.
It is easily missed as it is not an obvious link. Happens to me all the time when people integrate links in sentences like you did there.
Fully agree! But one of my goal in going active was to get rid of them definitely.( Well in fact i kept one pair of monstrous mkp (parralleled 100uf/630v can) to protect my tweeters... but hush hush, it's a secret!).
Erik, remember i came from pro audio world. Dolby is not making this processor anymore, they sell the rights and technology (from my processor) to LabGruppen. This is now the core of the processor you can find in their bigger amplifier.
Billshurv, you should have read the whole thread including the links...
The Rod Elliott article explain this clearly.
This is one of the 'supposed' benefits. But from my experience this 'clarity' thing is one of the aspects which hit me with this principle (each time i've heard a modded speaker or comparaison between passive/active mode on PA speakers). Does it came from IM improvements, lacks of passive in signal path or something else... i don't know, but it's there for sure.
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Fully agree! But one of my goal in going active was to get rid of them definitely.( Well in fact i kept one pair of monstrous mkp (parralleled 100uf/630v can) to protect my tweeters... but hush hush, it's a secret!).
Erik, remember i came from pro audio world. Dolby is not making this processor anymore, they sell the rights and technology (from my processor) to LabGruppen. This is now the core of the processor you can find in their bigger amplifier.
Billshurv, you should have read the whole thread including the links...
The Rod Elliott article explain this clearly.
Sorry, was mixing up a lot of different configurations. Obviously, going fully active means eliminating any tweeter caps. I just meant, most commercial speaker owners could gain a lot from a cheap cap upgrade. Almost as much as treating their rooms.
Best,
Erik
We agree Erik, no problem. Hybrid set up as you mentionned earlier ( or explained in Rod Elliott article) is a nice solution too. Most of the advantage are taken (bass chanel is isolated from medium/high) but much lesser cost involved.
For caps my remarks aimed at the finest speakers i've heard (which was passive i repeat) where cap selection and crossover works was truly state of the art, in choice of parts, but in design choice too. The one i'm thinking of have just 2 issues: first technically they can't keep up at high volume as theyr active twins (exist in both), 2 their price...
For the room... yes! yes! yes!
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sorry in french but if you can read it, worth it:
Zippy - Enceinte intégralement asservie - 29923222 - sur le forum Discussions Générales - 1472 - du site Homecinema-fr.com
JCB the man behind the project is a smart one (he is an acoustician too... he designed some really nice studios in France) and a nice guy! I would be really pleased to hear the zippys but i haven't! Bet they are very very good!
Heh, motion feedback should have made it to the list of technology that didn't go very far. Velodyne is still using tech but apparently it wasn't very game changing or they would have no real competition.
I've never heard them by the way, this is just a comment on the state of the market. Like, AMT tweeters have really broad acceptance and multiple manufacturers jumping on the bandwagon now that the patents have expired. Also tells me the patent holders weren't very smart in monetizing the tech.
Best,
Erik
I've never heard them by the way, this is just a comment on the state of the market. Like, AMT tweeters have really broad acceptance and multiple manufacturers jumping on the bandwagon now that the patents have expired. Also tells me the patent holders weren't very smart in monetizing the tech.
Best,
Erik
Infinity servostatik had a good innings. And don't forget the kii 3
electronics
This uses voltage and current feedback around the amplifier to do cone monitoring. I would say there could just be a renaissance of the technology now DSP is so cheap. But I could be wrong.
electronics
This uses voltage and current feedback around the amplifier to do cone monitoring. I would say there could just be a renaissance of the technology now DSP is so cheap. But I could be wrong.
Velodyne, is particular sonicwise, maybe that's the reason there is not much a wide spread of it. Users are so used to distortion in bass reproduction that when you take it out of the equation, they feel like something is missing...
And with the advent of Bose systems or even better smartphones and Beats audio thingy to listen music we can surely tell that Golden Ears are around ourself! Be safe all of you who spread good sound to our youth, golden age is still behind you!
Exactly the same as the zippy! And if your interested all schematics are availlable thru the thread i linked, even an open version that could be used with your own loudspeaker. JCB managed to get +-0.2db variation across whole frequency response... 20hz to 18khz 0.4db max deviation... stellar! <3
In fact for the masses this is still more or less 'confidential' technology. I've already met some speakers from the early 80's which used this kind of tech. Problem once they're broken it's really dificult to fix them.
Nevertheless in pro audio this is still used by some brands with great results: direct from the 2000 area :
http://www.meyersound.com/sites/default/files/x-10_ds.pdf
Note the advance of the design: the ancestor of econowave, just a little more andvanced technologicaly.
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