kjello
Super Member
Thanks
Got 3 sets of 10 pc for around 3 dollars total from eBay (china)
Knobs are black instead of gray, but fits well and looks ok I think
I replaced all of them
Thanks
Got 3 sets of 10 pc for around 3 dollars total from eBay (china)
Knobs are black instead of gray, but fits well and looks ok I think
I replaced all of them
nedseg
Well-Known Member
https://dbxpro.com/en/products/driverack-venu360
Just sayin'...
Just sayin'...
kjello
Super Member
Only done some 'straight through' tests yet, its very quiet, and I cant say I can notice the extra component in the 'chain'
I have to use some XLR/RCA adapters tho, My pre doesent have XLR but my amps do...
I was thinking testing on some other speakers than my mains... Just dont want to mess up.
kjello
Super Member
Not yet...on my Klipsch speakers... but that is the main plan
Mr. Blifil
Member
I don't see a role for an active crossover driving those speakers. The double sets of connectors enable biwiring and biamping. Biwiring can be done without one, using one stereo amplifier. The sole benefit for biwiring is slightly reduced opportunity for intermodulation distortion. JBL, for one, says it's an audible improvement; I've never tried it.
The benefits of biamping include avoiding the insertion loss of the built-in crossover, removing the big inductors in line between the amp and woofer when there is a low pass below 500Hz, using two smaller amps instead of one big one, and using different amps for LF and treble.
The low pass portion of a crossover can sometimes be quite simple, but not always. Because of rising response in a woofer the low pass may require an asymmetrical slope. I once owned a biampable speaker that switched the low pass out of the circuit but left in the conjugate across the woofer terminals and also left in the entire high pass for the treble and supertweeter. High pass sections of crossovers almost always involve frequency compensation, especially with horns. Where there is an axial offset of acoustic centers of drivers, as there usually is with horns, the crossover frequency is not arbitrary but is rather chosen to reduce raggedness in the crossover region resulting from the offset. Crossover frequencies listed in speaker specs are often nominal since one or another of the sections may involve staggered poles.
There is no way of bypassing the internal crossover network in the RF-83 without tearing into them and changing the internal wiring. If it were advisable to bypass the internal crossover, the manufacturer would have made it possible. Removing the jumpers from the input panel simply separates the hi pass and low pass portions of the crossover. They must remain in the circuit because it is almost always the case that a speaker's crossover network does two things: it divides the frequencies, and it compensates for frequency response anomalies in the raw drivers to make the overall response flatter and remove colorations and suck outs. Both of these functions--frequency division and EQ--must be replicated with external instruments if the internal crossover is bypassed. The frequency division might be easy, but knowing where to apply EQ would be impossible without a virtual test lab.
The only benefit to biamping that speaker would be to apply additional power or to use different amps for treble and bass. Either should be done without an external crossover and using the existing connectors unjumpered.
Aside from all that, in the manual the manufacturer strongly discourages biamping in general. I believe their reasons would include all that I have said above.
The benefits of biamping include avoiding the insertion loss of the built-in crossover, removing the big inductors in line between the amp and woofer when there is a low pass below 500Hz, using two smaller amps instead of one big one, and using different amps for LF and treble.
The low pass portion of a crossover can sometimes be quite simple, but not always. Because of rising response in a woofer the low pass may require an asymmetrical slope. I once owned a biampable speaker that switched the low pass out of the circuit but left in the conjugate across the woofer terminals and also left in the entire high pass for the treble and supertweeter. High pass sections of crossovers almost always involve frequency compensation, especially with horns. Where there is an axial offset of acoustic centers of drivers, as there usually is with horns, the crossover frequency is not arbitrary but is rather chosen to reduce raggedness in the crossover region resulting from the offset. Crossover frequencies listed in speaker specs are often nominal since one or another of the sections may involve staggered poles.
There is no way of bypassing the internal crossover network in the RF-83 without tearing into them and changing the internal wiring. If it were advisable to bypass the internal crossover, the manufacturer would have made it possible. Removing the jumpers from the input panel simply separates the hi pass and low pass portions of the crossover. They must remain in the circuit because it is almost always the case that a speaker's crossover network does two things: it divides the frequencies, and it compensates for frequency response anomalies in the raw drivers to make the overall response flatter and remove colorations and suck outs. Both of these functions--frequency division and EQ--must be replicated with external instruments if the internal crossover is bypassed. The frequency division might be easy, but knowing where to apply EQ would be impossible without a virtual test lab.
The only benefit to biamping that speaker would be to apply additional power or to use different amps for treble and bass. Either should be done without an external crossover and using the existing connectors unjumpered.
Aside from all that, in the manual the manufacturer strongly discourages biamping in general. I believe their reasons would include all that I have said above.
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kjello
Super Member
That would mean an active filter cant do what a passive filter can.
Mr. Blifil
Member
No. It does mean an external active crossover that simply divides frequencies will not do everything an internal passive network with compensation is doing.
kjello
Super Member
I havent looked into the speakers or crossovers yet, I guess one could easily just disconnect the factory wiring from the drivers and bypass all with new direct wiring to amps. I may see some challenge in the 3 woofer impedance. The rest should be simple to just try out, running 4 identical amplifier channels.
But I have to admit I'm hesitating, speakers are good from factory imho
I don't want this to sound like an absolute 'I'm right and you are wrong' kind of statement, because both passive and active systems have their advantages/disadvantages, but there's a lot of misinformation about this. So here goes.
One of the oddities of connecting amps directly to the drivers (active system) is that where drive impedance slope with frequency should be compensated for in a passive crossover, the directly connected amplifier doesn't care about this and is not affected by it. The reason that a passive crossover requires compensation is that the driver impedance directly affects the crossover frequency of the crossover itself. Also, voicecoil heating will have a similar effect. You cannot alter either parameter (it's just physics), so you have to do your best to compensate for them. A low pass filter crossover point will drift upwards with increasing driver impedance and the high pass filter will drift downwards. This leads to a hump developing across the crossover region as the crossover point start to overlap, which might explain why some speakers can start to sound harsher at high volume levels. Some manufacturers purposely try to counter this by setting high and low pass filter centre points at different frequencies (low pass is lower and high pass is higher) to allow for driver coil heating to bring the crossover into alignment. This will tend to give a rather lacklustre sound at low levels though, which doesn't aid selling them in the hi-fi shop. You need an exciting sound to make them sell etc [salesman speak].
Because active filters operate in the line level signal domain they don't 'see' the speakers and are not affected by any of this. Additionally, the amplifier power is not just doubled. With a passive bi-amping setup, each amp is still carrying the full audio range signal. The unwanted bit is wasted in the speaker crossover (with a treble amp in a 3way passive, about 85% of amp output is wasted as heat in the crossover). With true active operation the bass amp does not have the midrange signal superimposed on the bass signal (same with midrange amp). The end result, as the power spread in most music centres around 350Hz, is that the bass and mid amps can actually go close to 4 time louder. In practice this means that at the same overall room volume level the amplifiers have 3 times more transient headroom than when running the entire audio signal. It's probably best to use power amps with the same gain and adjust for different driver efficiencies at the crossover output.
One of the oddities of connecting amps directly to the drivers (active system) is that where drive impedance slope with frequency should be compensated for in a passive crossover, the directly connected amplifier doesn't care about this and is not affected by it. The reason that a passive crossover requires compensation is that the driver impedance directly affects the crossover frequency of the crossover itself. Also, voicecoil heating will have a similar effect. You cannot alter either parameter (it's just physics), so you have to do your best to compensate for them. A low pass filter crossover point will drift upwards with increasing driver impedance and the high pass filter will drift downwards. This leads to a hump developing across the crossover region as the crossover point start to overlap, which might explain why some speakers can start to sound harsher at high volume levels. Some manufacturers purposely try to counter this by setting high and low pass filter centre points at different frequencies (low pass is lower and high pass is higher) to allow for driver coil heating to bring the crossover into alignment. This will tend to give a rather lacklustre sound at low levels though, which doesn't aid selling them in the hi-fi shop. You need an exciting sound to make them sell etc [salesman speak].
Because active filters operate in the line level signal domain they don't 'see' the speakers and are not affected by any of this. Additionally, the amplifier power is not just doubled. With a passive bi-amping setup, each amp is still carrying the full audio range signal. The unwanted bit is wasted in the speaker crossover (with a treble amp in a 3way passive, about 85% of amp output is wasted as heat in the crossover). With true active operation the bass amp does not have the midrange signal superimposed on the bass signal (same with midrange amp). The end result, as the power spread in most music centres around 350Hz, is that the bass and mid amps can actually go close to 4 time louder. In practice this means that at the same overall room volume level the amplifiers have 3 times more transient headroom than when running the entire audio signal. It's probably best to use power amps with the same gain and adjust for different driver efficiencies at the crossover output.
kjello
Super Member
I would also add that any amp that has a non switching class a operation, will stay "longer" in class a mode (higher effective output) to the driver coils. Also the speaker could be better set up to the listening room, with the use some kind of spectrum analyzer.
twiiii
Lunatic Member
The Pioneer DL 23 was the best cross over from the period, If you got the coin,you want Bryston 10 B today. Stereo 2 way or mono 3 way. Large selection of frequencies and crossover slopes with very low distortion and huge signal to noise. It you want a single Stereo unit and have the coin Accuphase has made some great units over the years. Mcintosh makes the MEN 220 as a RoomPerfect EQ, but can be programmed as a 2 channel two way crossover, with different slopes. Plus it has 5 or 6 parametric filters you can use to get the freq, response curve closer to your liking before turning loose the 1/12 octave room perfect automated filters.. You'll need a FFT analyzer or a real time spectrum analyzer to get the setting right with a Series 1 calibrated microphone\.
Mr. Blifil
Member
Well, how did it go? I've been wondering what you tried and how it turned out for you?
kjello
Super Member
I decided to delay this project, as Im building a new amplifier and my best reference to test it, is my long owned and used speakers.
Thanks for asking, I will report back for shure
SimplySound
Kent Engineering & Fondry
I'm with Powertech on this one. Eric Squires makes a good point in this thread.
So, take an amplifier that can produced a maximum of 10V rms. In music, most of that will be used by the bass, below 200 Hz. A lot of it. Maybe 8 V rms. If the bass takes all 8, you are left with 2 V for the rest. If you put a high pass filter before it, the amp is now able to reserve all of the 10V for mid to treble.
And I'm thinking Marchand XM66, per Mr. Pig!
So, take an amplifier that can produced a maximum of 10V rms. In music, most of that will be used by the bass, below 200 Hz. A lot of it. Maybe 8 V rms. If the bass takes all 8, you are left with 2 V for the rest. If you put a high pass filter before it, the amp is now able to reserve all of the 10V for mid to treble.
And I'm thinking Marchand XM66, per Mr. Pig!
Going with the active solution, there are in fact a few other elements that may be relevant to overall sound quality. So called 'damping factor' (I would prefer a term like 'amplifier driver control factor' because I believe it is a more relevant term) with a passive system is more or less taken to a factor of 1 because of the effect of the large inductors used in the LF crossover. Once a driver reaches the required extent of motion at signal peak amplitude the signal falls and the driver is pulled back towards the central equilibrium position by the mechanical suspension. The energy produced by the driver coil is supposed to be controlled by the amplifier output stage (damping), but most of it never gets there as it is absorbed by the bass series inductor. This energy is a) converted into heat and b) sits in opposition to the next rising signal which is a applied by the amplifier. With a true active system the amplifier output stage is connected directly to the driver and is able to fully control the driver motion. One of the perceived advantage of this is that the bass response is often reported to appear to be more dynamic (as much as I hate audiophool speak, I don't know any other way to put the point across - sorry). The increase in available amplifier headroom has been mentioned and this is calculable, as is the lack of interaction between the amplifiers where a transient bass range overload, which maybe inaudible in itself, in passive systems can have a detrimental and audible effect on higher frequency reproduction. This can be due to the generation of harmonics interacting with higher frequency reproduced signals.
In terms of driver frequency response non-linearity which can be corrected in passive crossovers by utilising bandpass filtering elements, I agree entirely that this is difficult to achieve with an active crossover unless a DSP is used which can fully map the effective response curves. The issue with crossover frequency shifting due to driver coil heating effects on a passive crossover doesn't apply to active systems. Some of the anomalies which may occur at different overall volume levels can be adjusted to suit the listening environment.
One of the most important design elements with either passive or active configurations that is often overlooked is overall system planning. With commercial passive speaker systems the objective is to produce a speaker system which will work with a range intended amplifiers where driver characteristics are catered for in the crossover and cabinet design. Active systems require to be designed as a system incorporation all elements from the preamp, crossovers, and amplifiers through to the loudspeaker drivers and cabinet design. This leads to difficulties with future system flexibility (e.g. changing components in the future). Simple upgrades are just not feasible. Some of the most important design priorities therefore have to include careful selection of drivers which exhibit smooth frequency response curves and similar or compatible dispersion characteristics, particularly in the preferred crossover regions. This point in itself is a major issue when people are trying to change or adapt existing passive systems to active operation. A system which was designed for passive operation will not always lend itself to function correctly within an active system.
In terms of driver frequency response non-linearity which can be corrected in passive crossovers by utilising bandpass filtering elements, I agree entirely that this is difficult to achieve with an active crossover unless a DSP is used which can fully map the effective response curves. The issue with crossover frequency shifting due to driver coil heating effects on a passive crossover doesn't apply to active systems. Some of the anomalies which may occur at different overall volume levels can be adjusted to suit the listening environment.
One of the most important design elements with either passive or active configurations that is often overlooked is overall system planning. With commercial passive speaker systems the objective is to produce a speaker system which will work with a range intended amplifiers where driver characteristics are catered for in the crossover and cabinet design. Active systems require to be designed as a system incorporation all elements from the preamp, crossovers, and amplifiers through to the loudspeaker drivers and cabinet design. This leads to difficulties with future system flexibility (e.g. changing components in the future). Simple upgrades are just not feasible. Some of the most important design priorities therefore have to include careful selection of drivers which exhibit smooth frequency response curves and similar or compatible dispersion characteristics, particularly in the preferred crossover regions. This point in itself is a major issue when people are trying to change or adapt existing passive systems to active operation. A system which was designed for passive operation will not always lend itself to function correctly within an active system.
whoaru99
Epic Member
Bass peak demands perhaps but in terms.of average power around 350Hz is equal power point between bass and mid/high.
Below that the ratio of bass to mid/high power actually decreases.