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 Post subject: Re: Fully active x- over
PostPosted: Wed Apr 20, 2016 3:29 pm 
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None of mine are there. In fact I don't see any JBL at all? :? :lol:

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 Post subject: Re: Fully active x- over
PostPosted: Wed Apr 20, 2016 4:14 pm 
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Philosophil wrote:
None of mine are there. In fact I don't see any JBL at all? :? :lol:
JBL speakers don't need 'optimization'. :)

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 Post subject: Re: Fully active x- over
PostPosted: Wed Apr 20, 2016 5:14 pm 
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JBL speakers don't speak Scottish...


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 Post subject: Re: Fully active x- over
PostPosted: Wed Apr 20, 2016 5:36 pm 
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MEYER SOUND,
now were talkin
Oops these are PA Bins


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 Post subject: Re: Fully active x- over
PostPosted: Wed Apr 20, 2016 7:25 pm 
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Does anyone know the significance of the asterisks beside some of the speakers? (including my Keilidhs which I use as surrounds)

jst_canuck wrote:

"Certainly easier for all concerned if the signal path is ALL digital to avoid such A/D conversion problems :idea:

Even the power amp section(s) that push and pull each speaker driver may operate without dedicated D/A by operating in Class D."

I am not certain, but I believe the only "digital" component in a Class D amp is the lightweight transformer, the actual amplification is completely analogue or have I got that wrong :?:

Mac.

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 Post subject: Re: Fully active x- over
PostPosted: Wed Apr 20, 2016 7:32 pm 
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mac1 wrote:
Does anyone know the significance of the asterisks beside some of the speakers? (including my Keilidhs which I use as surrounds)


http://www.linn.co.uk/music-systems/tec ... timisation
Quote:
* SPACE Optimisation+ compatible


mac1 wrote:
I am not certain, but I believe the only "digital" component in a Class D amp is the lightweight transformer, the actual amplification is completely analogue or have I got that wrong :?:

Mac.

Correct-ish


https://en.m.wikipedia.org/wiki/Class-D_amplifier
Quote:
A class-D amplifier or switching amplifier is an electronic amplifier in which the amplifying devices (transistors, usually MOSFETs) operate as electronic switches, and not as linear gain devices as in other amplifiers. The signal to be amplified is a train of constant amplitude pulses, so the active devices switch rapidly back and forth between a fully conductive and nonconductive state. The analog signal to be amplified is converted to a series of pulses by pulse width modulation, pulse density modulation or other method before being applied to the amplifier. After amplification, the output pulse train can be converted back to an analog signal by passing through a passive low pass filter consisting of inductors and capacitors. The major advantage of a class-D amplifier is that it can be more efficient than analog amplifiers, with less power dissipated as heat in the active devices.


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 Post subject: Re: Fully active x- over
PostPosted: Thu Apr 21, 2016 5:28 am 
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Thank you Jared

I guess I should have checked Wikipedia first :roll: , very interesting.

It seems that most Class D amplifiers operate in the following manner (also taken from Wikipedia)

"The analog signal to be amplified is converted to a series of pulses by pulse width modulation, pulse density modulation or other method before being applied to the amplifier. After amplification, the output pulse train can be converted back to an analog signal by passing through a passive low pass filter consisting of inductors and capacitors."

That sounds like an ADA converter on steroids! which is not the object of the exercise as a purely digital signal path was being discussed.

This comment also from Wikipedia suggests that some D class amps can accept a digital input, I have read this several times and it made my brain hurt :D .

"The term "class D" is sometimes misunderstood as meaning a "digital" amplifier. While some class-D amps may indeed be controlled by digital circuits or include digital signal processing devices, the power stage deals with voltage and current as a function of non-quantized time. The smallest amount of noise, timing uncertainty, voltage ripple or any other non-ideality immediately results in an irreversible change of the output signal. The same errors in a digital system will only lead to incorrect results when they become so large that a signal representing a digit is distorted beyond recognition. Up to that point, non-idealities have no impact on the transmitted signal. Generally, digital signals are quantized in both amplitude and wavelength, while analog signals are quantized in one (e.g. PWM) or (usually) neither quantity.

I think I'll stay with good ole analog amps.

Mac.

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 Post subject: Re: Fully active x- over
PostPosted: Thu Apr 21, 2016 10:24 am 
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mac1 wrote:
Thank you Jared

I guess I should have checked Wikipedia first :roll: , very interesting.

It seems that most Class D amplifiers operate in the following manner (also taken from Wikipedia)

"The analog signal to be amplified is converted to a series of pulses by pulse width modulation, pulse density modulation or other method before being applied to the amplifier. After amplification, the output pulse train can be converted back to an analog signal by passing through a passive low pass filter consisting of inductors and capacitors."

That sounds like an ADA converter on steroids! which is not the object of the exercise as a purely digital signal path was being discussed.

This comment also from Wikipedia suggests that some D class amps can accept a digital input, I have read this several times and it made my brain hurt :D .

"The term "class D" is sometimes misunderstood as meaning a "digital" amplifier. While some class-D amps may indeed be controlled by digital circuits or include digital signal processing devices, the power stage deals with voltage and current as a function of non-quantized time. The smallest amount of noise, timing uncertainty, voltage ripple or any other non-ideality immediately results in an irreversible change of the output signal. The same errors in a digital system will only lead to incorrect results when they become so large that a signal representing a digit is distorted beyond recognition. Up to that point, non-idealities have no impact on the transmitted signal. Generally, digital signals are quantized in both amplitude and wavelength, while analog signals are quantized in one (e.g. PWM) or (usually) neither quantity.

I think I'll stay with good ole analog amps.

Mac.

Much research by engineering labs worldwide to use the speaker driver inductance itself as the "inductor" in Class D amplifiers.
Works best if amplifier has very short connections to the speaker :(
In the end, the movement of the speaker motor and cone is analog to actually create sounds.

Let's encourage work on this amplifier technology so we can all benefit from convenient, great sound quality at decent cost 8)

One really great potential spin-off from having individual amps for each driver is to have servo-feedback from the speaker cone to "correct" the waveform from the amplifier.

Is it possible to then have a speaker with low distortion, say 0.5% :idea:

What might that sound like :?:


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 Post subject: Re: Fully active x- over
PostPosted: Thu Apr 21, 2016 11:07 am 
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drummermitchell wrote:
MEYER SOUND,
now were talkin
Oops these are PA Bins


Actually, Meyer Sound, a company that manufactures only active speakers, uses the same Class H (a variant of Class D) power amps in their high-end studio monitors as they do in their PA speakers.

There are, of course, significant differences between their PA and studio speakers.

In the X-10T monitors I have, the first major difference is that the LF drivers achieve extremely linear response from 23 Hz to 950 Hz by incorporating a motor with 1.5 million Maxwells total magnet flux. That's 5 to 8 times the total magnetic flux of comparable 15" and 18" drivers from JBL, TAD, Beyma, Tannoy, etc..

The second difference from their PA speakers is that the X-10T has a microphone mounted an inch or two in front of the LF driver. Using proprietary servo circuitry developed with engineers at the University of California, the input from the amps and the output from the speaker are constantly compared in real time with minute adjustments made, as necessary, to maintain precise responsiveness and complete linearity of cone movement.

The result is electrostatic-like delicacy, clarity and impulse response combined with PA-like SPL capability. The downside is that they do require periodic (every couple of years is recommended) electronic recalibration by a Meyer Sound technician. The upside is, well, how they sound with any type of music and at any SPL level (up to 125 dB continuous output with 136 decibel peaks).

So, yes, digital amplification, or rather amplification with digital elements, does enable advances in sound reproduction that are impossible with conventional amplifier technology.

However, unlike most class D and H amplifiers, those in the X-10 and X-10T output in class A up to 40 watts.

http://www.meyersound.com/sites/default ... -10_ds.pdf


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 Post subject: Re: Fully active x- over
PostPosted: Thu Apr 21, 2016 5:28 pm 
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dr.joe wrote:
drummermitchell wrote:
MEYER SOUND,
now were talkin
Oops these are PA Bins


Actually, Meyer Sound, a company that manufactures only active speakers, uses the same Class H (a variant of Class D) power amps in their high-end studio monitors as they do in their PA speakers.

There are, of course, significant differences between their PA and studio speakers.

In the X-10T monitors I have, the first major difference is that the LF drivers achieve extremely linear response from 23 Hz to 950 Hz by incorporating a motor with 1.5 million Maxwells total magnet flux. That's 5 to 8 times the total magnetic flux of comparable 15" and 18" drivers from JBL, TAD, Beyma, Tannoy, etc..

The second difference from their PA speakers is that the X-10T has a microphone mounted an inch or two in front of the LF driver. Using proprietary servo circuitry developed with engineers at the University of California, the input from the amps and the output from the speaker are constantly compared in real time with minute adjustments made, as necessary, to maintain precise responsiveness and complete linearity of cone movement.

The result is electrostatic-like delicacy, clarity and impulse response combined with PA-like SPL capability. The downside is that they do require periodic (every couple of years is recommended) electronic recalibration by a Meyer Sound technician. The upside is, well, how they sound with any type of music and at any SPL level (up to 125 dB continuous output with 136 decibel peaks).

So, yes, digital amplification, or rather amplification with digital elements, does enable advances in sound reproduction that are impossible with conventional amplifier technology.

However, unlike most class D and H amplifiers, those in the X-10 and X-10T output in class A up to 40 watts.

http://www.meyersound.com/sites/default ... -10_ds.pdf

Wow, I'd really like to hear these working in the right room!

Just 1 small point that Class H operation is a variation of Class AB linear amplification.
Looks as if these boxes include analog amplifiers :?:
Additional circuitry with Class H reduces the power dissipation in the amplifier output transistors by switching the power supply voltage to either a high (maximum) or low level depending on the output power required.
Operation in Class A mode below 40W would then use the low level power supply voltage :idea:

I'm thinking that Marketing just can't bring themselves to actually say "DSP" so they use terms like "Black Box" for the section that processes the feedback information to correct the drive signal. Always the chance it is not a DSP, but when the shoe fits...... :lol:


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 Post subject: Re: Fully active x- over
PostPosted: Fri Apr 22, 2016 6:44 am 
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drummermitchell wrote:

Just 1 small point that Class H operation is a variation of Class AB linear amplification.
Looks as if these boxes include analog amplifiers :?:
Additional circuitry with Class H reduces the power dissipation in the amplifier output transistors by switching the power supply voltage to either a high (maximum) or low level depending on the output power required.
Operation in Class A mode below 40W would then use the low level power supply voltage :idea:

I'm thinking that Marketing just can't bring themselves to actually say "DSP" so they use terms like "Black Box" for the section that processes the feedback information to correct the drive signal. Always the chance it is not a DSP, but when the shoe fits...... :lol:


drummermitchell,

Thanks for the correction regarding class A, AB, D and H amplification.

As for the marketing department not mentioning DSP, I can't say what they were thinking, but certainly all Meyer Sound speakers and crossover/EQs are chock-full of DSP devices and circuits.

I had the Meyer Sound technician over a couple of months ago. What he does is connect the company's proprietary SIM3 audio analyzer device [ http://www.meyersound.com/product/sim/sim3/ system ]—essentially a computer with specialized software—to a port on the back of the speaker and from this he gets a full read-out, on a connected laptop, of all performance parameters. This includes diagnostics of distortion, impulse response, frequency response, etc., as well as EQ in real time.

And, of course, like most other pro audio companies these days, Meyer Sound's main external loudspeaker management device, called Galileo, is basically a computer dedicated to the manipulation of audio signals.

Sometimes I wonder how the speakers would perform if they used the same DSP devices for crossover and EQ, but coupled with big honkin' amps with massive old school linear power supplies and class A/B output stages. At the same time, though, it's hard to argue with the performance achieved. . .plus to offer 1825 Wpc of power with that kind of amplification would involve hundreds of pounds of hardware. . .


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 Post subject: Re: Fully active x- over
PostPosted: Fri Apr 22, 2016 7:03 am 
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dr.joe wrote:
drummermitchell wrote:

Just 1 small point that Class H operation is a variation of Class AB linear amplification.
Looks as if these boxes include analog amplifiers :?:
Additional circuitry with Class H reduces the power dissipation in the amplifier output transistors by switching the power supply voltage to either a high (maximum) or low level depending on the output power required.
Operation in Class A mode below 40W would then use the low level power supply voltage :idea:

I'm thinking that Marketing just can't bring themselves to actually say "DSP" so they use terms like "Black Box" for the section that processes the feedback information to correct the drive signal. Always the chance it is not a DSP, but when the shoe fits...... :lol:


drummermitchell,

Thanks for the correction regarding class A, AB, D and H amplification.

As for the marketing department not mentioning DSP, I can't say what they were thinking, but certainly all Meyer Sound speakers and crossover/EQs are chock-full of DSP devices and circuits.

I had the Meyer Sound technician over a couple of months ago. What he does is connect the company's proprietary SIM3 audio analyzer device [ http://www.meyersound.com/product/sim/sim3/ system ]—essentially a computer with specialized software—to a port on the back of the speaker and from this he gets a full read-out, on a connected laptop, of all performance parameters. This includes diagnostics of distortion, impulse response, frequency response, etc., as well as EQ in real time.

And, of course, like most other pro audio companies these days, Meyer Sound's main external loudspeaker management device, called Galileo, is basically a computer dedicated to the manipulation of audio signals.

Sometimes I wonder how the speakers would perform if they used the same DSP devices for crossover and EQ, but coupled with big honkin' amps with massive old school linear power supplies and class A/B output stages. At the same time, though, it's hard to argue with the performance achieved. . .plus to offer 1825 Wpc of power with that kind of amplification would involve hundreds of pounds of hardware. . .

+1
The real excitement will come from the masters of low manufacturing cost consumer level products using this same approach.
Somehow such systems will need to work consistently over their lifetime without regular visits from a Sound Technician :?:
Even 50W would be a great starting point for an introductory product.
Let's see who is up to the challenge :idea:


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