Thanks guys,
So,
The older pair uses regulated supply so I know the voltage
using your formula it will like
20V supply at 4A ; 2 mono block
4 x 2 x 20V = 115 x I
I = 160/115
so the actual mains current draw is 1.391 Amp
Correct?
Now the new pair is unregulated I am not sure the voltage
is using 400VA 22-0-22 CLC after 8 MUR860 ; set at Iq 3A;;
May be about the same?
Chris
So,
The older pair uses regulated supply so I know the voltage
using your formula it will like
20V supply at 4A ; 2 mono block
4 x 2 x 20V = 115 x I
I = 160/115
so the actual mains current draw is 1.391 Amp
Correct?
Now the new pair is unregulated I am not sure the voltage
is using 400VA 22-0-22 CLC after 8 MUR860 ; set at Iq 3A;;
May be about the same?
Chris
Actually, you wouldn't calculate 4A drawn at 20V because it's regulared and 4A are going to be drawn from a higher rail voltage and in turn from a lower transformer voltage, so you'd calculate the aperage being drawn from your transformer, and knowing the transformer's output voltage you could easily calculate the current drawn from the mains wiring from your amp.
purplepeople said:
Just get a certified electrician to install a dryer outlet in the living room for you. It would seem kind of weird but there would real bragging rights - "Oh yeah, my system is so powerful, it needs a dryer plug..."
ensen
Don't I have to replace the four transformers with 240V primary if I follow your advise?
I am just cautious and careful and want to know if all equipments are on at once will I overload the house line, hopefully the house comes with a circuit breaker that I have never inspect the fuse box, so I don't know, may be time to put a screw driver in the fuse box to increase the size of the fuse or buy bigger breaker uh?
Chris
Ea. house is equiped with two separate AC power lines (sharing common neutral). Ea. one is 120V or so, but because they are out of phase you can also use them for 240V. Regular house lines are 15A, so if you don't want to overload it, you can use an additional line, which runs separately from a fuse box. In this case it's nice to use the other (half) of a standard 240V supply. It has nothing to do with 240V transformers.
At my house I have 240v/415v 3 phase at 60 amps per phase at the fuseboard. Don't really need it but when the house was built 9 years ago I just paid AUD$200 extra for it because I liked the idea...purplepeople said:Just get a certified electrician to install a dryer outlet in the living room for you. It would seem kind of weird but there would real bragging rights - "Oh yeah, my system is so powerful, it needs a dryer plug..."
Anyway, something you never hear of people doing in hifi circles is making a power supply with a transformer running off each phase. If the combined output of the three transformers is full wave rectified with 6 diodes the ripple frequency is 300Hz (with 50Hz mains) and the actual ripple voltage only 2% even *before* you connect any filter caps. The regulation would be somewhat better too.
If you were going to go to the trouble of having a dedicated line from your power outlet back to the fuseboard, go the extra mile and try this too. Seriously big industrial psu's use this method.
Hello,
If you are looking for an easy active crossover design, I would recommend the National Semiconductor Application Note AN-346 available at their website. I have not build the crossover, but I have built the RAII equalization circuit also described in that document and was very pleased with the result.
Someday, when I have the physical space for it, I plan to try biamping.
Regards,
Mike L.
If you are looking for an easy active crossover design, I would recommend the National Semiconductor Application Note AN-346 available at their website. I have not build the crossover, but I have built the RAII equalization circuit also described in that document and was very pleased with the result.
Someday, when I have the physical space for it, I plan to try biamping.
Regards,
Mike L.
On the active xover thing, dont worry about adding opamps to the circuit, just use good ones and you'll be fine, OPA2134 OPA627, AD6010/20 ect.
On the creative soundblaster thingy, thats axactly what I do, do!
You can mess around with xovers and frequency steps to your hearts content until you get the frequencies which sound the best, then just make it in the xover!
Ive just finished etchin the PCB's for a 200 watt monobloc pair for driving the Bass in my system, and the PCB for the 3-way active xover. I have used biamping with active for bass to mid/treb for a while and have now got round to making the whole lot active.
Will let you know how it all goes later.
Tonite im gonna be soldering the amp boards.
On the creative soundblaster thingy, thats axactly what I do, do!
You can mess around with xovers and frequency steps to your hearts content until you get the frequencies which sound the best, then just make it in the xover!
Ive just finished etchin the PCB's for a 200 watt monobloc pair for driving the Bass in my system, and the PCB for the 3-way active xover. I have used biamping with active for bass to mid/treb for a while and have now got round to making the whole lot active.
Will let you know how it all goes later.
Tonite im gonna be soldering the amp boards.
5th element
Excellent idea using the Soundblaster and a PC to that purpose!
Just to bring this thread back on track, there is some information on this other thread that may be helpful to potential biampers especially if they're laying out their power supplies.
Excellent idea using the Soundblaster and a PC to that purpose!
Just to bring this thread back on track, there is some information on this other thread that may be helpful to potential biampers especially if they're laying out their power supplies.
May be I didn't do it right
I hooked up my 4 JLH mono blocks with Behringer CX3400 active cross over last night. Although there was no hum but the sound of bi-amping is really bad, actually a lot worst than normal bi-wiring.
Just my first impression with bi-amping, I don't see what all the fuss about..with all extra amps and cross over. no good at all...
Chris
I hooked up my 4 JLH mono blocks with Behringer CX3400 active cross over last night. Although there was no hum but the sound of bi-amping is really bad, actually a lot worst than normal bi-wiring.
Just my first impression with bi-amping, I don't see what all the fuss about..with all extra amps and cross over. no good at all...
Chris
Maybe the Behringer crossover wasn't up to the task? The active crossover in such setup is as important as the amp, so probably best recommendation is to build your own.
Properly implemented bi-amping shouldn't be worse than single amp. But some people don't even like bi-wiring. Did you compare bi-wire to single wire run?
Properly implemented bi-amping shouldn't be worse than single amp. But some people don't even like bi-wiring. Did you compare bi-wire to single wire run?
Chris,
I have a pair of JLH mono blocks and had a similar result with a chip solid state 4th order crossover.
It was terrible and un listenable so I have not returned to bi amping since.
However, in the Passlabs article on Phase Coherent Crossovers there are some interesting ways to operate an active with simple RC high pass filtering that you maybe able to adopt with some success.
Alternatively, buy a bread board as I did last night and potter around with your own discrete diy opamps or followers (see the passlabs diyopamp article and the Borbely articles part 1+2).
I plan to insert these simple designs into the signal path and do some subjective tests.
I will post the results in due course
macka
I have a pair of JLH mono blocks and had a similar result with a chip solid state 4th order crossover.
It was terrible and un listenable so I have not returned to bi amping since.
However, in the Passlabs article on Phase Coherent Crossovers there are some interesting ways to operate an active with simple RC high pass filtering that you maybe able to adopt with some success.
Alternatively, buy a bread board as I did last night and potter around with your own discrete diy opamps or followers (see the passlabs diyopamp article and the Borbely articles part 1+2).
I plan to insert these simple designs into the signal path and do some subjective tests.
I will post the results in due course
macka
macboy said:
I removed the stock external gold plated jumpers of the five way binding posts of my speakers, so one pair for the low and another pair for the mid-high isolated sections. I thought the speakers are ready for bi-amping..The cross over frequency of the speakers stated in Mirage web site as 1.8K so I adjusted the active cross over accordingly. The model is M490i , do you think I still need to bypass the internal crossovers?
Chris
Tried an MTM with bi-amp and it sounded like crap. On the other hand Linkwitz is getting excellent results and all kinds of awards with his active systems.
In my HO getting voicing an active speaker is just has hard as voicing a passive one, most likely harder given the number of variables.
If you think you are going to get good sound by slapping together a LR from ESP and pick a random cutoff frequency with a couple of handpicked drivers you better think again.
I would seriously question any claim of great sound unless you heard it yourself first.
In my HO getting voicing an active speaker is just has hard as voicing a passive one, most likely harder given the number of variables.
If you think you are going to get good sound by slapping together a LR from ESP and pick a random cutoff frequency with a couple of handpicked drivers you better think again.
I would seriously question any claim of great sound unless you heard it yourself first.
The intermal crossovers MUST BE DISCONNECTED, not just bypassed. If they are still connected to the drivers in any way they will effect the sound. I have been bi-amping for years and it always sounds better to me than the internal crossovers as long as it is done correctly. Only going half way isn't a good idea or a good indicator of what is possible. Make sure to get the phasing correct. Go all the way and do it right and I think you will like what you hear. The key is to do it correctly.
Later BZ
Later BZ
My first attempts at biamping with active crossover were somewhat unsuccessful
I just thought I could use any random filter design found in the web and some arbitraty crossover frequencies
But I continued doing experiments for years and have been progressively finding the tips to get active crossovers right
The first thing that must be taken into account is that active crossover design is as critical as pasive ones design except in the fact that driver impedance no longer has to be compensated for
The complexity remains the same, driver-plus-box amplitude and phase response should be measured and/or simulated for each driver in the system, assuming perfect response for drivers will allways give bad results
Things that have to be compensated in active :
- Driver-plus-box lower rolloff if it's high enough to affect crossover overlap region
- Driver higher rolloff if it's low enough to affect crossover overlap region
- Any marked peaks or dips in the response of the driver [lets say more than +-3dB]
- Baffle step, this is very tricky
- Delays : the fact of having some drivers physically further than others, or having higher sound propagation times than others, can be corrected to some extent with phase-shifter circuits [up to maybe half a wavelenght or one wavelenght of the highest frequency considered], this is a serious advantage over passive filtering since with some tricky adjustment you can make the drivers to sum its response at the height of the ear in the listening position [assuming vertical placement] and to cancel out at other heights minimizing reflected sound in the floor and ceiling
[The same phase shifters can also be used to correct to some extent the pase shifts caused by driver rolloff in the overlap region, without correcting amplitude response, simply by appliying a similar phase shift to the other driver so both have similar phase response, this usually gives succesful summing in a simpler way]
Measuring anything inside a room is a bad idea since room acoustics will fool badly the measurement, reflected sound may be stronger than direct sound at some frequencies except when the room has been carefully acoustically treated to prevent reflections
Then, the hard task is to develop one or more active filters capable of modifying driver-plus-box response in a way you get something very similar to the response of an ideal lowpass/highpass/bandpass filter, having the same phase response over all the overlap region and having a complementary amplitude response so little [+-1.5dB] dip or peak is generated when summing both drivers in this region
This is a time consuming task as it requires lots of experiments with different filters and lots of measurements and objetive listening tests [using the ear as a FFT to know if the drivers are summing or cancellyng in the overlap region]
If the drivers are summing right in the overlap region, reversing the polarity of one of them will make a great notch in this region, this is a stupid test but very very useful to find whats going on, I usually use a polarity switch with long wires from where I am listening to the speaker to be able to change it without moving
Adjusting delays is also very tricky, you have to place the two drivers overlapping in the vertical or horizontal axis and then listen moving vertically or horizontally triying to find a point where both drivers have the best summing in their overlap region
For example, if you found the best summing point is at more distance from the midrange driver than from the tweeter, you have to add the corresponding delay to the tweeter to move the "hot spot" [place where drivers sum better] to the front of the speaker cabinet [or to the point you desire, usually the listening point]
Going off-axis also causes phase response variations so the test has to be repeated in a try and error basis until you get the proper delay
All this tedious process has to be repeated for all overlap regions
But after all, you will end with a customized system performing far better than the original passive crossover
You can even get cheap drivers to sound right since yoy can compensate rollofs, peaks and dips to some extent
Also, smaller boxes can be used since you are compensating the lower rolloff of the driver-plus-box system in the crossover
Using this method with compression drivers and horns also gives outstanding results since the biggest problems when crossing over horns are the huge phase shifts at horn upper and lower rolloff [preventing them from summing properly in their overlap region] and different delays introduced by the propagation of the sound inside different horns
PD: Reading this is not recommended for subjetive-listening people as these guys are usually very happy hearing drivers cancelling out, lots of reflected sound [sometimes more than direct], standing waves, etc...
PD2: I love Linkwitz, i've read some old papers from 70s & 80s and they show the right philosophy. Why so little people has put it into practice it in the last 25 years?
I just thought I could use any random filter design found in the web and some arbitraty crossover frequencies
But I continued doing experiments for years and have been progressively finding the tips to get active crossovers right
The first thing that must be taken into account is that active crossover design is as critical as pasive ones design except in the fact that driver impedance no longer has to be compensated for
The complexity remains the same, driver-plus-box amplitude and phase response should be measured and/or simulated for each driver in the system, assuming perfect response for drivers will allways give bad results
Things that have to be compensated in active :
- Driver-plus-box lower rolloff if it's high enough to affect crossover overlap region
- Driver higher rolloff if it's low enough to affect crossover overlap region
- Any marked peaks or dips in the response of the driver [lets say more than +-3dB]
- Baffle step, this is very tricky
- Delays : the fact of having some drivers physically further than others, or having higher sound propagation times than others, can be corrected to some extent with phase-shifter circuits [up to maybe half a wavelenght or one wavelenght of the highest frequency considered], this is a serious advantage over passive filtering since with some tricky adjustment you can make the drivers to sum its response at the height of the ear in the listening position [assuming vertical placement] and to cancel out at other heights minimizing reflected sound in the floor and ceiling
[The same phase shifters can also be used to correct to some extent the pase shifts caused by driver rolloff in the overlap region, without correcting amplitude response, simply by appliying a similar phase shift to the other driver so both have similar phase response, this usually gives succesful summing in a simpler way]
Measuring anything inside a room is a bad idea since room acoustics will fool badly the measurement, reflected sound may be stronger than direct sound at some frequencies except when the room has been carefully acoustically treated to prevent reflections
Then, the hard task is to develop one or more active filters capable of modifying driver-plus-box response in a way you get something very similar to the response of an ideal lowpass/highpass/bandpass filter, having the same phase response over all the overlap region and having a complementary amplitude response so little [+-1.5dB] dip or peak is generated when summing both drivers in this region
This is a time consuming task as it requires lots of experiments with different filters and lots of measurements and objetive listening tests [using the ear as a FFT to know if the drivers are summing or cancellyng in the overlap region]
If the drivers are summing right in the overlap region, reversing the polarity of one of them will make a great notch in this region, this is a stupid test but very very useful to find whats going on, I usually use a polarity switch with long wires from where I am listening to the speaker to be able to change it without moving
Adjusting delays is also very tricky, you have to place the two drivers overlapping in the vertical or horizontal axis and then listen moving vertically or horizontally triying to find a point where both drivers have the best summing in their overlap region
For example, if you found the best summing point is at more distance from the midrange driver than from the tweeter, you have to add the corresponding delay to the tweeter to move the "hot spot" [place where drivers sum better] to the front of the speaker cabinet [or to the point you desire, usually the listening point]
Going off-axis also causes phase response variations so the test has to be repeated in a try and error basis until you get the proper delay
All this tedious process has to be repeated for all overlap regions
But after all, you will end with a customized system performing far better than the original passive crossover
You can even get cheap drivers to sound right since yoy can compensate rollofs, peaks and dips to some extent
Also, smaller boxes can be used since you are compensating the lower rolloff of the driver-plus-box system in the crossover
Using this method with compression drivers and horns also gives outstanding results since the biggest problems when crossing over horns are the huge phase shifts at horn upper and lower rolloff [preventing them from summing properly in their overlap region] and different delays introduced by the propagation of the sound inside different horns
PD: Reading this is not recommended for subjetive-listening people as these guys are usually very happy hearing drivers cancelling out, lots of reflected sound [sometimes more than direct], standing waves, etc...
PD2: I love Linkwitz, i've read some old papers from 70s & 80s and they show the right philosophy. Why so little people has put it into practice it in the last 25 years?
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