Was Missing doing designs with more Old School woofers.
Mechanical designed for massive bass in simple cabinets.
No Reflex , No transmission line or anything exotic.
Also was reminiscing my childhood.
Remembering the Radio Shack Catalog.
Which sold Raw Drivers for Diy.
And night after night dream up speaker builds.
Wishing to build all kinds of imagined systems.
Lots of the Big 12" and 15" woofers in the
Catalog were basic foam/ rubber surround poly cones
And so I was reminiscing and looking around
At Parts Express for, Fun easy Poly cone
hopefully cheap...with rubber surround.
Which resembled all those late nights
dreaming things up from the
" Shack" catalog
But somewhat modern easy approach
Full range assisted by a woofer
So I found a Fun 12"
12PR-8
To give Support to a 2.5" Woven Fiber/ Poly
Fullrange / Wideband
PC68-8
Modeled the 12" in simulator.
And ohh boy it is one of those guys.
Sealed, overemphasized
the bass area.
So in the real world half space, seems flatten
out pretty good, Baffle step around 280 Hz
No ports no BS just bass
All 140 liters of it
Using a 500 x 800mm Baffle
I started the usual " Virtual process"
of full space ,baffle diffraction, crossover...
yada yada yada
Well the summed up pretty So decided to
Draw up some pictures. To see if Im dumb
enough to build this Thing
Mechanical designed for massive bass in simple cabinets.
No Reflex , No transmission line or anything exotic.
Also was reminiscing my childhood.
Remembering the Radio Shack Catalog.
Which sold Raw Drivers for Diy.
And night after night dream up speaker builds.
Wishing to build all kinds of imagined systems.
Lots of the Big 12" and 15" woofers in the
Catalog were basic foam/ rubber surround poly cones
And so I was reminiscing and looking around
At Parts Express for, Fun easy Poly cone
hopefully cheap...with rubber surround.
Which resembled all those late nights
dreaming things up from the
" Shack" catalog
But somewhat modern easy approach
Full range assisted by a woofer
So I found a Fun 12"
12PR-8
To give Support to a 2.5" Woven Fiber/ Poly
Fullrange / Wideband
PC68-8
Modeled the 12" in simulator.
And ohh boy it is one of those guys.
Sealed, overemphasized
the bass area.
So in the real world half space, seems flatten
out pretty good, Baffle step around 280 Hz
No ports no BS just bass
All 140 liters of it
Using a 500 x 800mm Baffle
I started the usual " Virtual process"
of full space ,baffle diffraction, crossover...
yada yada yada
Well the summed up pretty So decided to
Draw up some pictures. To see if Im dumb
enough to build this Thing
Attachments
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Absolutely Good catch @profiguy
scenario with many full ranges " rising" response on this one is 1k to 2k.
Not visible of course, that is where the notch is.
But yes exactly, that artifact from the notch filter definitely shows visually. towards the top at 3K
as you noticed
can play around with the 18uF cap in the notch.
leaving coil and resistor the same.
Gives pretty nice range to play with the width or Q of the notch, just with the cap.
which bumps or raises the 3k
I have jumped to either extreme 18uF as shown or 15uF both work rather well.
22 to 27uf =brighter. 12uf to 10uf= too dark
scenario with many full ranges " rising" response on this one is 1k to 2k.
Not visible of course, that is where the notch is.
But yes exactly, that artifact from the notch filter definitely shows visually. towards the top at 3K
as you noticed
can play around with the 18uF cap in the notch.
leaving coil and resistor the same.
Gives pretty nice range to play with the width or Q of the notch, just with the cap.
which bumps or raises the 3k
I have jumped to either extreme 18uF as shown or 15uF both work rather well.
22 to 27uf =brighter. 12uf to 10uf= too dark
Im comfortable, familiar with this driver from other projects.
Even without the notch it is ok. Some music not even noticeable.
as fullrange. With a tweeter the 3k is in the filter not a issue.
Far as fullrange. Just the nature of the beast.
The high-end isn't harse. With this driver, bass is more the issue
If you run fullrange as with any small driver, bass not its thing.
At high levels. On a highpass as a mid/ high in this situation. all ok
im not familar with this exact woofer. but have built boxes
for drivers that behave mechanically like it.
of course you loose 6dB or so. But crossing at baffle step
bass gets impressive. really my main concern was 80 dB.
Im more a fan of 90 dB plus endeavors. But the tradeoff
is ok sometimes, because sealed bass with no reflex or lines
is nice.
Even without the notch it is ok. Some music not even noticeable.
as fullrange. With a tweeter the 3k is in the filter not a issue.
Far as fullrange. Just the nature of the beast.
The high-end isn't harse. With this driver, bass is more the issue
If you run fullrange as with any small driver, bass not its thing.
At high levels. On a highpass as a mid/ high in this situation. all ok
im not familar with this exact woofer. but have built boxes
for drivers that behave mechanically like it.
of course you loose 6dB or so. But crossing at baffle step
bass gets impressive. really my main concern was 80 dB.
Im more a fan of 90 dB plus endeavors. But the tradeoff
is ok sometimes, because sealed bass with no reflex or lines
is nice.
If your baffle compensation lowers your sensitivity, you do have the option to bi-amp.
So I'm looking at this plot. It seems power is thinning just below 1kHz and going wide for a couple of octaves after that. This might offer some character to the sound. It suggests you could stand to take the crossover a bit lower.
So I'm looking at this plot. It seems power is thinning just below 1kHz and going wide for a couple of octaves after that. This might offer some character to the sound. It suggests you could stand to take the crossover a bit lower.
Yes indeed agree.
I was trying to be a weasel and get away with slightly cheaper coil.
Which I did with the 6.8 mH when around 8.2 mH probably more ideal
The horizontal, works rather well with smaller coil
But yes as noticed little dip vertical at -40 degrees.
Lots of designs somewhat ignore the vertical.
But I find it important. good point
It works very well with slightly lower crossover
Aka 8.2 mH coil instead of 6.8mH
Additional adjustments required.
I will post findings and corrected network in a min
I was trying to be a weasel and get away with slightly cheaper coil.
Which I did with the 6.8 mH when around 8.2 mH probably more ideal
The horizontal, works rather well with smaller coil
But yes as noticed little dip vertical at -40 degrees.
Lots of designs somewhat ignore the vertical.
But I find it important. good point
It works very well with slightly lower crossover
Aka 8.2 mH coil instead of 6.8mH
Additional adjustments required.
I will post findings and corrected network in a min
I have two PC68-4 from another project (one has a dented center), some thick & thin XPS foam, a DATS, and a Umik-1/REW, and can measure outside on a ladder (haven't tried a ground-plane type measurement).
But as far as speaker/crossover design I am the equivalent of a pig looking at a radio.
If you want, I am willing to get the woofers to build and measure it.
Not willing to go MDF, I don't have any good high-ply, no void plywood.
interesting sounds good.
be awesome to see the build and measurements
I would have to change the crossover for the 4 ohm drivers.
For your build
Which would be rather simple.
moving forward I will post the crossover schematic for the build.
the baffle is wide for the 12" and follows the golden ratio.
The wider aspect also yields a flatter response for the PC68 wideband.
only importance to just follow the dimensions, since crossover
is designed for it.
I will start and post plan for basic cabinet dimensions
and driver placement.
be awesome to see the build and measurements
I would have to change the crossover for the 4 ohm drivers.
For your build
Which would be rather simple.
moving forward I will post the crossover schematic for the build.
the baffle is wide for the 12" and follows the golden ratio.
The wider aspect also yields a flatter response for the PC68 wideband.
only importance to just follow the dimensions, since crossover
is designed for it.
I will start and post plan for basic cabinet dimensions
and driver placement.
Low crossover where driver centre-to-centres are close to the “magic” quarter wavelength.
dave
@shrub0
Yes definitely, vertical gets ignored sometimes.
I spend a decent amount of time with positioning and crossover adjustments.
But for the most part the layout is straight forward.
and works out well due to the basic theory and layout
I'm somewhat obsessed with vertical response and make sure the models accurate.
I thought I had it to the best it could be. Then encouraged to make further
adjustments in post #7. Really did turn rather well.
As noted in other threads I have a thing with very flat friendly impedance curves
as well.
Models are always subjective, but do everything possible to make them accurate.
Horizontal is relatively easy, Vertical another story.
Since you can feed the speaker and quickly see how phase interacts.
I have done small adjustments in the past when modeling when looking
at vertical. Since impedance and vertical is kinda my pet peeve
Yes definitely, vertical gets ignored sometimes.
I spend a decent amount of time with positioning and crossover adjustments.
But for the most part the layout is straight forward.
and works out well due to the basic theory and layout
I'm somewhat obsessed with vertical response and make sure the models accurate.
I thought I had it to the best it could be. Then encouraged to make further
adjustments in post #7. Really did turn rather well.
As noted in other threads I have a thing with very flat friendly impedance curves
as well.
Models are always subjective, but do everything possible to make them accurate.
Horizontal is relatively easy, Vertical another story.
Since you can feed the speaker and quickly see how phase interacts.
I have done small adjustments in the past when modeling when looking
at vertical. Since impedance and vertical is kinda my pet peeve
yep pretty much, and a small wide makes it incredible easy.
likewise most crossovers for 2 way are rather high.
so you run into the usual phase mess.
lower approach makes phase incredible friendly
and very low crossover makes dialing in the potential for
great bass relatively easy as well . being right at full space losses
far as using a small wideband on wide baffle.
nice flat response.
looking at the possibility for 3 way.
the small wideband makes very small tweeter possibly.
3/4" or 19mm very easy to use, no waveguides.
So another aspect is off axis for high frequency
would also appear to good to be true.
In reality it approaches actually being possible.
using a wide baffle small mid.
and a 1) woofer with specific mechanical properties
which likely would confuses or intimidate most.
all adds up to= very good bass , no lines or reflex.
( my impedance pet peeves)
2) small mid /small tweeter.
good vertical and good high frequency off axis
ironical and comically on a monkey coffin
enclosure which most would quickly ignore.
oh well lol.
golden ratio cabinet , and funny
most the ideal driver positions end up
also being very close to the ratio
nice flat response.
looking at the possibility for 3 way.
the small wideband makes very small tweeter possibly.
3/4" or 19mm very easy to use, no waveguides.
So another aspect is off axis for high frequency
would also appear to good to be true.
In reality it approaches actually being possible.
using a wide baffle small mid.
and a 1) woofer with specific mechanical properties
which likely would confuses or intimidate most.
all adds up to= very good bass , no lines or reflex.
( my impedance pet peeves)
2) small mid /small tweeter.
good vertical and good high frequency off axis
ironical and comically on a monkey coffin
enclosure which most would quickly ignore.
oh well lol.
golden ratio cabinet , and funny
most the ideal driver positions end up
also being very close to the ratio
definitely laughed out loud to that one
think you'll be fine , check post #12
But the comical analogy was to good to pass up
I couldn't help to photoshop the quote into reality LOL
Correct.
Depends how your data is collected.
If your collecting microphone data on each driver center,
then yes you need to specify
its listening position.
you can do the same thing in the diffraction tool
depending on mic position.
otherwise yes correct it is rather important.
overall phase would be completely different
but actually it makes position change much easier
doing as you describe. if position needs to be changed.
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