ACD
Could you please elaborate on what you mean by 99% equal to Beolab 5 bass drivers-
Are they from same factory/ supplier- spec's..?
I've heard the Beolab 5 and thought the bass was their best feature- though overall a very nice sound indeed! -I could probably live with them quite happily...
Could you please elaborate on what you mean by 99% equal to Beolab 5 bass drivers-
Are they from same factory/ supplier- spec's..?
I've heard the Beolab 5 and thought the bass was their best feature- though overall a very nice sound indeed! -I could probably live with them quite happily...
If all the drivers had the same sensitivity through their bandpass regions, when mounted in the appropriate enclosures, then yes, you would need the same theoretical peak-peak voltage ability to maintain the homogenity of the frequency response.
Unfortunately the sensitivity of each driver will vary quite considerably.
Chances are if you use a wide bandwidth driver for the midrange, then the baffle step will boost it's sensitivity halfway through the range.
If you use a sealed box for the bass, chances are you will have to EQ it for a flat response (and the room will almost certainly demand that you do so) Again the sensitivity of the driver will vary as you descend below it's in-box resonance.
Unfortunately the sensitivity of each driver will vary quite considerably.
Chances are if you use a wide bandwidth driver for the midrange, then the baffle step will boost it's sensitivity halfway through the range.
If you use a sealed box for the bass, chances are you will have to EQ it for a flat response (and the room will almost certainly demand that you do so) Again the sensitivity of the driver will vary as you descend below it's in-box resonance.
LineSource:
Thanks again. I see your points 😉
I will need a little more reading on this subject, before making my desicion........
george a:
It should be exactly the same unit, except for the glue used to bind the foam/rubber surrounding (there was some doubt about if the glue used in these units I got could live up to the 10 times power safety margin demanded fore the BeoLab 5 😉
Thanks again. I see your points 😉
I will need a little more reading on this subject, before making my desicion........
george a:
It should be exactly the same unit, except for the glue used to bind the foam/rubber surrounding (there was some doubt about if the glue used in these units I got could live up to the 10 times power safety margin demanded fore the BeoLab 5 😉
Energy distribution in music spectrum
But for active speakers, this power distribution-across-spectrum question is a constant one. This graph I finched (from somewhere I don't remember) helps a lot. I'm currently buildling a two-way (which, with Sreten's inputs, will probably become a 2.5-way) active speaker, where I'm using five Gainclones for the five drivers (one tweeter, four midbass units). Considering that my xo freq is 2.5KHz, this means I'm setting up four times as much power for the 20-2500Hz range as the upper portion. Seems broadly right, in fact a bit top-heavy, considering that I'll be using LT for eq. LT can easily eat up a lot of power.... just a 6dB boost can require four times the power rating (16 Gainclones instead of four!)
So, your percentage figures above are very heavily dependent on your xo freqs.
PS: Has the real-time clock on the new diyaudio server gone for a walk? It used to show me my time of post accurately, corrected for my local time. Now it's off by exactly two hours, i.e. it's as if the software believes India is 30 degrees east of where it is. Anyone else sees this problem?
I too am fascinated by active speakers, and I would probably never build a traditional amp-in-a-box wired to passive speakers standing separately, if I could help it. Passive high-current xo just doesn't make sense, if one can afford the time/money for multiple amps.ACD said:
But for active speakers, this power distribution-across-spectrum question is a constant one. This graph I finched (from somewhere I don't remember) helps a lot. I'm currently buildling a two-way (which, with Sreten's inputs, will probably become a 2.5-way) active speaker, where I'm using five Gainclones for the five drivers (one tweeter, four midbass units). Considering that my xo freq is 2.5KHz, this means I'm setting up four times as much power for the 20-2500Hz range as the upper portion. Seems broadly right, in fact a bit top-heavy, considering that I'll be using LT for eq. LT can easily eat up a lot of power.... just a 6dB boost can require four times the power rating (16 Gainclones instead of four!)
So, your percentage figures above are very heavily dependent on your xo freqs.
PS: Has the real-time clock on the new diyaudio server gone for a walk? It used to show me my time of post accurately, corrected for my local time. Now it's off by exactly two hours, i.e. it's as if the software believes India is 30 degrees east of where it is. Anyone else sees this problem?
Attachments
I'm always suspicious of any 'average' power distribution curve for music, since one man's chart for a solo female vocalist accompanied by strings is totally inappropriate for some hard hitting drum'n'bass. Given that you can do so much more in terms of filtering with an active speaker, and that decent kit amps have reached very low price points, surely it makes more sense to go for more than you could conceivably need, for headroom's sake?
I totally agree. IIRC, this graph was from a source which had sampled a wide variety of music types to arrive at an average. Moreover, some friends had done some analyses of power distribution across the spectrum with music samples they were curious about, and this graph tallied with their observations fairly closely. So the graph provides a good starting point, even if it doesn't totally reflect your specific music pieces.Mudge said:
But I don't see the need for the graph to be very accurate. I can always use this as a starting point, and then overspec the drivers and (more importantly) the amps, so that I have enough headroom in every portion of the spectrum. Finally, what will really blow out my drivers will be the absolute power level going to it from the amp, not just the distribution. If I can ensure that my tweeter and its amp will have a higher rating than I'll ever need from my tweeter at sane listening levels, then I'm home free. And considering that people are using Gainclones with passive-xo-speakers, it seems that most drivers in active-xo speakers (other than the big woofers) will be adequately driven by a Gainclone each, for sane listening levels. One more point in support of this is the fact that there's no energy-sapping passive xo between the amp and the driver, thus often raising power efficiency by maybe 6dB or more compared to a passive xo scenario.
Are you sure India hasn't moved due to your recent elections ? 😉
Sorry for the off-topic (and for being naughty, but soemtimes I simply can't resist) !
Regards
Charles
P.S. : My experience with LF EQ-ing (like LTF or other shelving EQ)is that it is worth every watt spent as long as you don't overdo it (e.g. like trying to get 20 Hz out of 4 inch diver or anything as crazy). Most recordings don't have much spectral content below 50 to 60 Hz (demanding less power than expected) but still profit from an in-room response going below 30 hz.
Sigh... Don't get an Indian started on these elections, you'll never hear the end of it. In fact, some citizens of our great country at this point in time might have told you that India had indeed shown signs of moving, but Westwards, to Italy. These people will also tell you how relieved they are that it didn't happen. 😀phase_accurate said:
No apologies needed to me... the entire country seems to have only polls and the skirmishes for ministerial berths on their minds. 😀 Cartoonists here are having an absolute field day. Check Amul's Website for their famous cartoons... (Amul is one of India's best-loved brands.) 😀
An externally hosted image should be here but it was not working when we last tested it.
Yes, my Gooroo Angshoo too says the same thing. He says that if you can't get decent output out of your speakers till about 30Hz, the sound is a bit "thin". So that's what I'm aiming for with my design.
Active speakers can work very well with quite modest driving
power per driver. This is because they can manage voltage
swings across each driver that would need a very powerful
single amplifier.
For example : 100w bass, 50w midrange and 30w treble is
equivalent to a 500W single amplifier for wideband transient
peaks, though it obviously isn't 500w in the bass.
The nature of music vs test signals is an issue in properly
designing an active speaker, and IMO active speakers should
be at least 3 way, and give the opportunity to use modest
output but high quality amplifiers for midband and treble.
As loudspeaker distortion is pretty much related to input power
high output requirements are IMO better met by high sensistivity
drivers rather than high input powers.
For example doubling up the PL18's will increase efficiency by 3dB.
And of course to qualify as "high end" the mechanical and
acoustic engineering of the loudspeaker must be top notch.
I don't really see the sense in choosing a lower c/o frequency
where you have excursion worries for the mid bass driver,
I'd simply lift it somewhat to say ~ 300Hz.
Though my simulations indicate the PL18 in a small sealed
enclosure doesn't excursion limit with 100W until below 100Hz.
🙂 sreten.
power per driver. This is because they can manage voltage
swings across each driver that would need a very powerful
single amplifier.
For example : 100w bass, 50w midrange and 30w treble is
equivalent to a 500W single amplifier for wideband transient
peaks, though it obviously isn't 500w in the bass.
The nature of music vs test signals is an issue in properly
designing an active speaker, and IMO active speakers should
be at least 3 way, and give the opportunity to use modest
output but high quality amplifiers for midband and treble.
As loudspeaker distortion is pretty much related to input power
high output requirements are IMO better met by high sensistivity
drivers rather than high input powers.
For example doubling up the PL18's will increase efficiency by 3dB.
And of course to qualify as "high end" the mechanical and
acoustic engineering of the loudspeaker must be top notch.
I don't really see the sense in choosing a lower c/o frequency
where you have excursion worries for the mid bass driver,
I'd simply lift it somewhat to say ~ 300Hz.
Though my simulations indicate the PL18 in a small sealed
enclosure doesn't excursion limit with 100W until below 100Hz.
🙂 sreten.
Reminds me of something I've been thinking of, but quietly, for the last few months, partly because of my friend Angshu's recent obsession: Class A. I guess a great way to get useful SPLs with Class A would be to multi-amp, and use Class As for the mids and highs, don't you think?sreten said:
At least the guru Pass thinks that way and I think he is not that wrong (even though one can live with many types of amps with actives, my personal favourite is class-D).
Regards
Charles
I'd be tempted to go with a Class-D for the bass driver, a conventional Class AB for the midrange and some very exotic Class A for the treble, in conjunction with a very efficient tweeter. If you can push the distortion products out of the passband for each driver then it makes the subjectively less impressive sounding amplifiers much easier on the ears.
I also like the simulated results of using low Mms high efficiency bass drivers with high EBP in sealed boxes. Group delay is very low, and if you look at the sensitivity you will find that despite not having decent natural extension, if you think in terms of power requirements for LT, you quite often get more bass for your watts from them.
I also like the simulated results of using low Mms high efficiency bass drivers with high EBP in sealed boxes. Group delay is very low, and if you look at the sensitivity you will find that despite not having decent natural extension, if you think in terms of power requirements for LT, you quite often get more bass for your watts from them.
tcpip:
Regarding the power requirements for different drivers in a speaker, this was just an "old" golden rule that I learned 20 years ago, when working shortly with commercial PA speakers.. I KNOW!!! PA is not High End HiFi, however speakers must have some simularities...
sreten:
Thanks...
There seems to be some different opinions about the Vifa PL18's power handling at lower frequencies....
A change from 200Hz up to 300Hz with a 24dB active crossover must move some of the chritical power to the woofer.....
By the way.... My PL18's are special made with 94 dB/1W sensitivity!
Regarding the power requirements for different drivers in a speaker, this was just an "old" golden rule that I learned 20 years ago, when working shortly with commercial PA speakers.. I KNOW!!! PA is not High End HiFi, however speakers must have some simularities...
sreten:
Thanks...
There seems to be some different opinions about the Vifa PL18's power handling at lower frequencies....
A change from 200Hz up to 300Hz with a 24dB active crossover must move some of the chritical power to the woofer.....
By the way.... My PL18's are special made with 94 dB/1W sensitivity!
Since you are from Denmark there are a some other Danish manufacturers to choose from than just D-S-T, e.g. :
http://www.audiotechnology.dk
Regards
Charles
http://www.audiotechnology.dk
Regards
Charles
Do you guys who live in Denmark just walk across to the Vifa/SS factory and get a custom-built pair of drivers made during lunch break or something? 😀ACD said:
Here in our country, the DIY community was considering confetti and brass bands when we heard that we finally have one legal, regular dealer of the D-S-T drivers. Just half a dozen models, but what the hell! 😀
JensRasmussen said:
NO. I guess you have never had the opportunity to monitor the outputs of an electronic crossover with a scope. I further guess that you are not acquainted with the waveform of music signal.
Mudge said:
No, no, no.
Konnichiwa,
If this is implemented well in terms of managing dispersion and LF output vs. extension this can work well.
Does being the equal of B&O's speakers make them good? I would not think so. No offence meant, but if I wanted a serious 15" Driver I know where I would look and B&O's OEM's are not on the list.
You can get driver with excellent management of thermal issues, excellent management of Magnet Field consistency for the voicecoil (plus gentle compression on really wide voicecoil swings) and competent implementation of distortion reducing mechanisms ain the Pro Audio Range of any one of a number of reputable manufacturers.
As you are active flat frequency response as such would not be a requirement at all.
I would try to push the Midrange X-Over either below around 1KHz or above around 4KHz. In fact, if the X-Over is placed at 4KHz and the tweeters dispersion controlled you get just right match with the usually near ideal "house curve" off axis and you can use the X-Over "dip" off axis strategically by placing it as "BBC Dip".
It is a frequency less than ideal. In order to controll dispersion at that low a frequency you need to go for Dipole/Cardiode radiators or use large waveguides, which would lend themselves better to being active radiation surfaces.
Don't worry, virtually ANY Home HiFi Driver will sound like that. If you want hgh SPL without compression and excessive distortion there is noit much in the "HiFi" driver ranges that makes sense. Progress straight to serious Pro-Drivers if that is what you want.
Well, you could use a decent 10" to cover to around 250Hz (no higher) and cover above that with a pure midrange driver(perhaps smaller diameter that the PL18?), not a bad idea at all.
Or you could really go for it and use 12-15" Coaxial Pro-Driver as "Wideband 2-Way" with a subwoofer coming in below around 100Hz and a Supertweeter above 10KHz.
Such a system can be designed with a sensitivity in the 98db/2.83V/1m sensitivity for the upper Bass/Lower Midrange with a realistic peak power handling of several 100 VA. It will provide a matching dispersion pattern between lower midrange and upper midrange (plus reasonable pattern control down to 200..300Hz). And if you correct the physical offset between woofer and compression driver (by delaying the woofer) you can get a impulse coherent point source covering most of the musical relevant range while being capable of > 120db peaks with minimal compression and low distortion.
Then simply add a suitable "overtone reproducer" (aka SUpertweeter) and a suitable "Superwoofer". I'd be looking for a 21" or larger woofer, so we get a reasonable dynamic range and a Supertweeter with response up to around 40KHz, prohbably hornloaded.
The resultant speaker could be pretty compact 24" X48" and would be truely outstanding. With around a kilowatt for the superwoofer, at least 400VA undistorted for the 15" Cone and 100VA for the compression driver we are seriously cooking.
Sayonara
ACD said:
If this is implemented well in terms of managing dispersion and LF output vs. extension this can work well.
ACD said:
Does being the equal of B&O's speakers make them good? I would not think so. No offence meant, but if I wanted a serious 15" Driver I know where I would look and B&O's OEM's are not on the list.
You can get driver with excellent management of thermal issues, excellent management of Magnet Field consistency for the voicecoil (plus gentle compression on really wide voicecoil swings) and competent implementation of distortion reducing mechanisms ain the Pro Audio Range of any one of a number of reputable manufacturers.
As you are active flat frequency response as such would not be a requirement at all.
ACD said:
I would try to push the Midrange X-Over either below around 1KHz or above around 4KHz. In fact, if the X-Over is placed at 4KHz and the tweeters dispersion controlled you get just right match with the usually near ideal "house curve" off axis and you can use the X-Over "dip" off axis strategically by placing it as "BBC Dip".
ACD said:
It is a frequency less than ideal. In order to controll dispersion at that low a frequency you need to go for Dipole/Cardiode radiators or use large waveguides, which would lend themselves better to being active radiation surfaces.
ACD said:
Don't worry, virtually ANY Home HiFi Driver will sound like that. If you want hgh SPL without compression and excessive distortion there is noit much in the "HiFi" driver ranges that makes sense. Progress straight to serious Pro-Drivers if that is what you want.
ACD said:
Well, you could use a decent 10" to cover to around 250Hz (no higher) and cover above that with a pure midrange driver(perhaps smaller diameter that the PL18?), not a bad idea at all.
Or you could really go for it and use 12-15" Coaxial Pro-Driver as "Wideband 2-Way" with a subwoofer coming in below around 100Hz and a Supertweeter above 10KHz.
Such a system can be designed with a sensitivity in the 98db/2.83V/1m sensitivity for the upper Bass/Lower Midrange with a realistic peak power handling of several 100 VA. It will provide a matching dispersion pattern between lower midrange and upper midrange (plus reasonable pattern control down to 200..300Hz). And if you correct the physical offset between woofer and compression driver (by delaying the woofer) you can get a impulse coherent point source covering most of the musical relevant range while being capable of > 120db peaks with minimal compression and low distortion.
Then simply add a suitable "overtone reproducer" (aka SUpertweeter) and a suitable "Superwoofer". I'd be looking for a 21" or larger woofer, so we get a reasonable dynamic range and a Supertweeter with response up to around 40KHz, prohbably hornloaded.
The resultant speaker could be pretty compact 24" X48" and would be truely outstanding. With around a kilowatt for the superwoofer, at least 400VA undistorted for the 15" Cone and 100VA for the compression driver we are seriously cooking.
Sayonara
phase_accurate:
Yes I know audio technology😉
Can't just afford them 😀
tcpip:
Yes!! Denmark is a very small country, so we all have our lunch break in the same cafeteria (also D-S-T) 😀
No! When being a diy'er for 25 years or so, you get to know people, who knows someone who once said "hello" to a guy, that maybe can get you what you need...
My PL18's are not espicially made for me, however Vifa makes a lot of customized versions for different speaker builders. And then you just have to wait until your speaker pusher got the right stuff on stock 😉
Bill Fitzpatrick:
Thats my point... 😉
Yes I know audio technology😉
Can't just afford them 😀
tcpip:
Yes!! Denmark is a very small country, so we all have our lunch break in the same cafeteria (also D-S-T) 😀
No! When being a diy'er for 25 years or so, you get to know people, who knows someone who once said "hello" to a guy, that maybe can get you what you need...
My PL18's are not espicially made for me, however Vifa makes a lot of customized versions for different speaker builders. And then you just have to wait until your speaker pusher got the right stuff on stock 😉
Bill Fitzpatrick:
Thats my point... 😉
Kuei Yang Wang:
Thanks for your input 😉
However I have been tweeking with these speakers for a long time, and have found the mid and tweeters that suits my ears.....
So I have no plans at all for replacing these with other high sensitivity drivers.....
Please forget all about wattage and sensitivity......
Can I get a better undistorted sound from a 4-way active speaker than from a 3-way system, and will 2 extra 6½ or one 8"/10" upper bass be the solution ????
Thanks 😉
Thanks for your input 😉
However I have been tweeking with these speakers for a long time, and have found the mid and tweeters that suits my ears.....
So I have no plans at all for replacing these with other high sensitivity drivers.....
Please forget all about wattage and sensitivity......
Can I get a better undistorted sound from a 4-way active speaker than from a 3-way system, and will 2 extra 6½ or one 8"/10" upper bass be the solution ????
Thanks 😉
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