although it's obscure if you search high impedance drivers you should come across the old Philips (i believe) 1000 ohm driver and some high impedance amp output designs.
or are you thinking differently?
or are you thinking differently?
Yea I know about active speakers but are the amps in them designed to accommodate the t/s parameters of the drivers or would those amps be suitable for a range of speakers as most amps are?
Actually it not a strange thought altogether. Being in the theatre business for almost 20 years, the best live and reliable monitor speakers on stage proved to be active speakers. Extra wiring needed, but worth all of it. The performers were all pleased by the controlled and vivid sound.
Having this in mind, why do we put both the 'controller' (the preamp with selector, volume control, and 'the rest') and the 'load driver' (main-loudspeaker amplifier) together in a box, whereas having them at there appropiate location things might become easier to control (different meaning) and benificial to all involved equipment and experience?
Hence the preference to build pre's and main's separate on the DIY platform, placing the pre next to the sofa or relax spot and the main near the transducers.
Someway this resembles my personal setup at the residence. And I like it.
It's worth to ponder about and considerate before a haphazard build of the next ultimate amp-thing. Plenty of time to do some inhome shuffling I'd say these days!
Having this in mind, why do we put both the 'controller' (the preamp with selector, volume control, and 'the rest') and the 'load driver' (main-loudspeaker amplifier) together in a box, whereas having them at there appropiate location things might become easier to control (different meaning) and benificial to all involved equipment and experience?
Hence the preference to build pre's and main's separate on the DIY platform, placing the pre next to the sofa or relax spot and the main near the transducers.
Someway this resembles my personal setup at the residence. And I like it.
It's worth to ponder about and considerate before a haphazard build of the next ultimate amp-thing. Plenty of time to do some inhome shuffling I'd say these days!
it's not to say schemes like a Linkwitz transform aren't being used in powered speaker designs and these days with DSP all manner of correction/tailoring can come to bear.
and most amp modules in powered speakers are to my knowledge still of traditional design and can be used as "general purpose".
and most amp modules in powered speakers are to my knowledge still of traditional design and can be used as "general purpose".
When experimenting with the Slewmaster series of amps we figured out we could actually tailor the amplifier to some speakers. We found if the speakers could use a little extra umpf in the bass region the VFA inputs such as Spooky / Leach type performed well. If your speakers were very well endowed in the bass region the CFAs like the Kypton-ND were a little better at high frequency detail.
As far as I know, TS parameters is related to box only. I dont see why the amplifiers wont be compatible with other speakers. Unless the speakers are 100v line speakers, but then they not active
I brought up the question because I was wondering if there could have been a collaborative effort by Kef and Meridian back in the early days. They both coincidentally had products with the title 105, both of which I own; the Meridian 105 monos and the Kef 105 monitors, a beautiful match. Kef also produced drivers for Meridian's early active M series speakers. The Kef B300 12" drivers driven by the 105 monos make bass with definition that cuts like a knife, I mean even at the lowest octaves. I have not heard detail like that from anywhere else. However they were stand alone products from separate companies. Before I purchased the Kefs in 1978, I auditioned the B&W 801s with the Meridian 105s. The 801s were more money but the Kef 105s were better sounding imo. Bass through the 801s was woolly in comparison.
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You can get good and bad setups of powered and unpowered speaker systems.
Most discrete amps are made to be low output impedance to match most speakers.
If you want to mess with the sound add dsp, graphic equalisation or tone controls.
I ran a mobile disco for 5 years without a tone control.
It also wasn't stereo just mixed stereo to mono.
No one every commented that the sound was bad.
Most discrete amps are made to be low output impedance to match most speakers.
If you want to mess with the sound add dsp, graphic equalisation or tone controls.
I ran a mobile disco for 5 years without a tone control.
It also wasn't stereo just mixed stereo to mono.
No one every commented that the sound was bad.
DSP active crossovers with one amplifier directly connected to each speaker allow some amplifier specialization.
Example:
A modest wattage Class-AB power amplifier with heavy Class-A bias could be designed for a tweeter
A normal wattage Class-AB power amplifier with optimal 26mv bias could be designed for a midrange
A high wattage Class-D amplifier could be designed for the woofer/subwoofer (1 per driver)
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Flexible DIY Chassis: 2 amplifiers for stereo speakers -OR- up to 4 mono driver amplifiers
Example:
A typical DIY stereo Class-AB construction with heatsinks along the left and right cabinet sides could be designed in a modular manner with a full heatsink length PCB designed just for the N- output transistors(resistors, capacitors), PLUS a separate small PCB holding input+driver circuits. Each full length output PCB would have jumpers which would allow separating the N-outputs into two sub-groups. This design would allow each driver PCB to connect to one of the two driver subsets per side. 2-channels, 3-channels, 4-channels.
Example:
A modest wattage Class-AB power amplifier with heavy Class-A bias could be designed for a tweeter
A normal wattage Class-AB power amplifier with optimal 26mv bias could be designed for a midrange
A high wattage Class-D amplifier could be designed for the woofer/subwoofer (1 per driver)
-------------
Flexible DIY Chassis: 2 amplifiers for stereo speakers -OR- up to 4 mono driver amplifiers
Example:
A typical DIY stereo Class-AB construction with heatsinks along the left and right cabinet sides could be designed in a modular manner with a full heatsink length PCB designed just for the N- output transistors(resistors, capacitors), PLUS a separate small PCB holding input+driver circuits. Each full length output PCB would have jumpers which would allow separating the N-outputs into two sub-groups. This design would allow each driver PCB to connect to one of the two driver subsets per side. 2-channels, 3-channels, 4-channels.
I had a dynakit ST70 modified to work with LWE III speakers. L.W. Erath to be specific. He incorporated a feedback mechanism in the speaker that linked into the feedback circuit of the amp. Cost $70 to have the amp modified with jones plugs. Great bass out of 10" woofers, decent sound otherwise out of a $130 (1972) speaker. Don't know what the feedback pickup was. A tweeter blew & Dad threw them away when I stored them in his garage while I was in the Army.
The ACE-bass subwoofer design used an amp with negative output impedance to cancel the voicecoil's resistance : ACE-bass amplifier design
Power amps have 0 ohms output impedance, to a close approximation, its called a high damping factor!
Seriously though very few drivers are designed for anything but low impedance (voltage source) drive, and it provides the lowest resonance peak too.
But yes in theory that's a good reason for having an active speaker - for instance with a servo feedback system on the bass driver to improve linearity at high excursion.
In an active speaker with multiple drivers, active crossover and multiple power amps each amp can be sized appropriate to the driver - this can be quite compact with multiple chipamps, and bridging for the bass driver.