gracias. Is the "Danzz" board the YJ red or blue board? So much localized vernacular across 180 pages...
Fullrange Assisted Subwoofer Technology (FAST). It relieves a fullrange driver of large excursions that are required to produce bass and so you get what sounds like a very nice fullrange speaker that has great low end extension with low distortion and higher SPL because cone movement from 200 Hz up is very little. If you have never heard a good fullrange driver before you are in for a real eye opener - jazz, simple girl and guitar stuff, small ensembles, stuff recorded where imaging is important - they all sound very good on a fullrange speaker. Primary to its advantage is the lack of phase altering crossovers in the critical 500 Hz to 5kHz range where imaging and soundstage are derived. There is also automatic spatial and time coherence in the reproduced sound because it is a point source.
Now with FAST, the bass fills in very nicely. If we can have a simple compact amp that is set up with a XO in the 200 Hz to 300 Hz range with the TPA3116 in a 2x4 config that would be great. The 2 channels going to the woofer would preferably be 100 watts PBTL monoblocks x 2. The full range can be 50 watts BTL stereo.
Technically, yes, fast is 2-way. But often called a fullrange because a single driver is used to cover 200 Hz to 20khz. Most 2-ways require 2 drivers to cover this range with a XO somewhere from 1khz to 3khz.
It's still a two-way system at it's core. The only difference between a FAST system and normal two-way is if the crossover frequency is placed at the upper or the lower end of the vocal range. Essentially a FAST system have a subwoofer and mid-high driver system that may go lower but struggles at the uppermost frequencies whereas a normal two-way with a mid-woofer and a tweeter is obviously better at the highest frequencies but struggle to go low.
There are also some who would say that crossing over lower ie below 80Hz into a mono sub positioned within about a 7 ft (i'm not sure of the technical reasons but I think it has to do with the wavelength of the bass signals) or less distance from either main left and right full rangers can produce a very satisfying sound field and realistic reproduction of the recorded space. That's the kind of application I think that the 2.1 boards here can really shine in. I've been pretty pleased with such a set up using a pair of AN12's and an 18" H Frame sub, and a similar set up with a pair of Quad electrostat's with a servo sub. Part of the key here would be a steep enough slope ie24dB.
Aha. thanks for the explanation xrk.
exactly what I will do with my w4-1337sd's and a 830500 or two when I finally get round to getting minidsp... using these amps of course.
exactly what I will do with my w4-1337sd's and a 830500 or two when I finally get round to getting minidsp... using these amps of course.
I think one of the main differences of a FAST vs a conventional 2-way is to put the XO location outside of the 'telephone band' so that any phase rotation doesn't affect the imaging and sound stage.
So back on subject, I am waiting for a couple of the green amp (Ybdz 2.0 on Aliexpress) boards to arrive - taken over 3 weeks now still not here... I will mount that in a small wooden craft box with a miniDSP and put RCA input jacks and qnty 8 banana binding post outputs for an active bi-amp all-in-one box for my FAST system.
Last edited:
That's true. A normal two-way indeed normally have it's crossover outside the human vocal range. Fundemental vocal range is 82hz (low E) to 1046.5hz (high C) with very few people being able to produce notes higher or lower than that. The advantage of the fast, although having the crossover in the critical vocal range, is that the ear is more forgiving to phase distortion at lower frequencies.
Please keep in mind that the middle C, commonly regarded as the center frequency from human voices, is 261.63hz. Much lower than most people that aren't musically trained think.
Most people, myself included, prefer a "true" full-range with "true" subwoofer assist cutting in somewhere under 80hz, or a conventional two-way with same subwoofer assist.
Last edited:
And the passband of the supporting woofer's frequencies is low enough compared to the baffle size that baffle step becomes an integral part of the original output level matching without worrying about having to account for it within the passband.
At least that's how I see it.
Guys, the 2.0 board from ChengZhi is not available anymore. I got an email that they have withdrawn this board due to quality issues. Frank and honest, that is good. I did not get a reply what the problem exactly is. I was curious what the function of the extra transistors was on this board.