2-way with ess heil amt
- Thread starter ceylon
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Values are pretty much spot on per the crossover calculator I've used before.
What is this resistor and cap in parallel with the woofer do? I was going to guess baffle step compensation. But most BSC circuits are an inductor and resistor in parallel I think (am no expert), not in series as shown below:
What is this resistor and cap in parallel with the woofer do? I was going to guess baffle step compensation. But most BSC circuits are an inductor and resistor in parallel I think (am no expert), not in series as shown below:
zobel network to stabilize the impedance of the woofer.
i believe...if thats stable, the mid-high crossover is stable as well.
I've not seen an impedance curve for this 15" woofer before now. The Zobel deals with the impedance rise that starts at about 200 Hz?
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i believe so, but its more above 500Hz. i understand very little and have used every tool at my disposal.
@Pete B, does this look right to you?
It's not the rise at the high end.., it's that peak at ~28Hz that the Zobal addresses.
isnt that the resonance frequency? does the zobel even see that?
heres why that zobel is there
TA Speaker Topics - Neutralizing L(e) with a Zobel
Technical discussion of neutralizing a loudspeaker's L(e) with a Zobel network
trueaudio.com
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I would not use an Lpad. Lpads have their own problems.
I would (and have) omit the Lpad and use a Mills resistor placed between the amp+ and the 22 uF cap. Make this piece easily replaceable because this is how you are ultimately going to tailor the Heil's volume to the system/room and this is where experimentation comes in. You will note that some of the very expensive speakers have replaceable resistors to tailor their sound to the room and that is what we are doing here.
A cap placed in this position will not affect the crossover point/slope to any degree but will reduce the volume.
I would (and have) omit the Lpad and use a Mills resistor placed between the amp+ and the 22 uF cap. Make this piece easily replaceable because this is how you are ultimately going to tailor the Heil's volume to the system/room and this is where experimentation comes in. You will note that some of the very expensive speakers have replaceable resistors to tailor their sound to the room and that is what we are doing here.
A cap placed in this position will not affect the crossover point/slope to any degree but will reduce the volume.
Ok...,
I had always figured that the capacitor was of a size (and they are big) so as to let signal pass to ground, through the resistor, so that the amp would see the parallel resistance of the resistor and the peak of the woofer pulling the combined impedance down to essentially just below that of the resistor so that amp is not looking at a 200 ohm load over that portion of the band.
So - often a Zobel IS needed but if the woofer has low inductance then it is not needed,
these woofers have copper in the magnet system to lower the inductance so I doubt
that a Zobel is needed. On the other hand I've shown many cases where it was needed
and left out in various designs.
I'm sure that the GRS 12" and 15" are very similar and here's a 1.5KHz crossover done
by EarlK for the GRS 12" that will probably work - note that no Zobel is used:
Do you know how to use Xsim?
these woofers have copper in the magnet system to lower the inductance so I doubt
that a Zobel is needed. On the other hand I've shown many cases where it was needed
and left out in various designs.
I'm sure that the GRS 12" and 15" are very similar and here's a 1.5KHz crossover done
by EarlK for the GRS 12" that will probably work - note that no Zobel is used:
Do you know how to use Xsim?
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Do you want/need baffle step compensation, most pro drivers do need it, that's why
EarlK used a much bigger inductor on the woofer. 2-3 mH is usually about right with an
8 ohm woofer. Less if you don't want baffle step.
What will you drive them with and do you have DSP or any kind of EQ?
EarlK used a much bigger inductor on the woofer. 2-3 mH is usually about right with an
8 ohm woofer. Less if you don't want baffle step.
What will you drive them with and do you have DSP or any kind of EQ?
When a woofer is crossed high say around or above 1 KHz and it has high inductance
you'll see a peak (often large like 5-10 dB) before rolloff in the electrical response of the
XO as loaded by the woofer. I've simply added a 20W large resistor (27-33) ohms across
the woofer to save on an additional cap and it often works.
you'll see a peak (often large like 5-10 dB) before rolloff in the electrical response of the
XO as loaded by the woofer. I've simply added a 20W large resistor (27-33) ohms across
the woofer to save on an additional cap and it often works.
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sounds like having it removes an unknown
how does the crossover (1.2kHz) i posted look to you?I'm sure that the GRS 12" and 15" are very similar and here's a 1.5KHz crossover done
by EarlK for the GRS 12" that will probably work:
no idea
if i need it i want it. i dont want it if its not.
hmn. my starting point is your sim of this driver in a 6.8uF bass reflex cabinet.
the baffle in my design is 24-25.5" wide.
how do i find out if i need baffle step compensation?
300WPC hybrid amp and a few others.
no dsp no eq.
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what will i see in the electrical response?
I'll edit the post, peak before the rolloff.
Also note (in the woofer FR previously posted) that the woofer passband is around 93dB,
but at 2KHz it peaks to 105 dB, that's over 10dB. The RC network across the woofer inductor,
if done right provides a notch in the XO to help tame that peak. This is a different peak from
the previous one mentioned.
but at 2KHz it peaks to 105 dB, that's over 10dB. The RC network across the woofer inductor,
if done right provides a notch in the XO to help tame that peak. This is a different peak from
the previous one mentioned.