Here's a schematic of the XO for the Heybrook HB2's -- the woofer for this one was destroyed by too much teenage activity so it is in the woofer replacement facility -- why is R1, C2, L3 connected to the tweeter "+" ? when I simmed it I note that it "shelves" the response. The tweeter seems to be the standard, government issue Audax 1"
Here's what the actual response into a resistive load looks like:
An externally hosted image should be here but it was not working when we last tested it.
Here's what the actual response into a resistive load looks like:
An externally hosted image should be here but it was not working when we last tested it.
Hi,
as drawn R1, C2 and L3 make no sense at all, especially as R1 is 560 ohm.
I suspect they are across the tweeter, r1 = 5.6 ohm
tuned to fs of the tweeter to flatten its impedance.
🙂/sreten.
as drawn R1, C2 and L3 make no sense at all, especially as R1 is 560 ohm.
I suspect they are across the tweeter, r1 = 5.6 ohm
tuned to fs of the tweeter to flatten its impedance.
🙂/sreten.
I have checked it twice and measured the value of R1 - 560 ohms - I posted this as I thought they may have made a mistake.
I redrew the schematic to better illustrate the tweeter connection.
I redrew the schematic to better illustrate the tweeter connection.
Hi,
well the L & C component values look right for the job.
R = 560R is completely pointless. Where its wired across is pointless.
Screw up ? hardwired ?
🙂/sreten.
well the L & C component values look right for the job.
R = 560R is completely pointless. Where its wired across is pointless.
Screw up ? hardwired ?
🙂/sreten.
No, I am not kidding:
An externally hosted image should be here but it was not working when we last tested it.
Hmmmm, here's a pair of phase-gain plots of the Woofer section of the Heybrook XO -- the first with R1, C2, L3 connected as illustrated, the second with the network disconnected:
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
I agree with sreten that it looks completely pointless to have them connected as in the diagram. It looks as if someone has misinterpreted a circuit diagram (twofold, first the 560 ohms, then where they are connected).
Is the diagram an original heybrook diagram or is it drawn from the actual components in the box? Are the components connected the same way in both speakers?
Is the diagram an original heybrook diagram or is it drawn from the actual components in the box? Are the components connected the same way in both speakers?
Easy there guys! I think you should be a little slower to assume that jackinnj cant even follow some wires! This circuit might not be familiar to you, but it obviously does something and I think jackinnj's idea here was to spark a conversation about it, not get accused of being stupid.
I mocked up the crossover both ways and the additional components are very interesting to me. They seem to be making the electrical phase more symetrical and closer to the a standard 4th order target (i cant tell which one). I am still new to this so I am not sure if I am even on the right track, but at least I give my fellow DIYers the benifit of the doubt 😉 .
-Chad
I mocked up the crossover both ways and the additional components are very interesting to me. They seem to be making the electrical phase more symetrical and closer to the a standard 4th order target (i cant tell which one). I am still new to this so I am not sure if I am even on the right track, but at least I give my fellow DIYers the benifit of the doubt 😉 .
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
-Chad
Hi,
As far as I'm concerned I can't see any audible point of the circuit.
If R should = 560R then the type of inductor is totally wrong.
If you redraw the circuit to look like a normal crossover it
looks like a blatant wiring and a component selection error.
The question was have they made a mistake, the answer IMO is yes.
Fc of the circuit is 1950Hz, which could easily be the tweeter Fs.
In that case it shoulds in parallel with the tweeter, R = 5.6 R.
Its also possible at 2K its there to control a bass unit resonance,
or shape the response. In that case it shoulds in parallel with the
bass unit, but R ? who knows ? 5.6R is the place to start.
But usually the latter is a series circuit (for good reasons), and
as the tweeter has a zobel my money is on the former option.
🙂/sreten.
Are both speakers the same as Svante asked ? (probably are)
As far as I'm concerned I can't see any audible point of the circuit.
If R should = 560R then the type of inductor is totally wrong.
If you redraw the circuit to look like a normal crossover it
looks like a blatant wiring and a component selection error.
The question was have they made a mistake, the answer IMO is yes.
Fc of the circuit is 1950Hz, which could easily be the tweeter Fs.
In that case it shoulds in parallel with the tweeter, R = 5.6 R.
Its also possible at 2K its there to control a bass unit resonance,
or shape the response. In that case it shoulds in parallel with the
bass unit, but R ? who knows ? 5.6R is the place to start.
But usually the latter is a series circuit (for good reasons), and
as the tweeter has a zobel my money is on the former option.
🙂/sreten.
Are both speakers the same as Svante asked ? (probably are)
The fact that it doesn't make sense as it is, and the fact that the circuit would make sense if 560R was replaced by 5R6 and if the circuit was connected in parallel with the tweeter, makes me think that it was originally intended for something else than it does now.
Humbly and without calling anyone stupid.
Adding a resistor that is 100 times the impedance level of the rest of the circuit can only be expected to change the current by 1 % or so. The differences in phase and amplitude as can be seen in the simulations all occur where the amplitude is low and doesn't matter much.
Humbly and without calling anyone stupid.
Adding a resistor that is 100 times the impedance level of the rest of the circuit can only be expected to change the current by 1 % or so. The differences in phase and amplitude as can be seen in the simulations all occur where the amplitude is low and doesn't matter much.
I can only surmise that the guy wiring the XO had a few pints prior to soldering it up.
Don't you just love that scene in "A Fish Called Wanda" in which Archie belittle's Otto's intelligence.
Don't you just love that scene in "A Fish Called Wanda" in which Archie belittle's Otto's intelligence.
I guess I just dont understand who you are saying has made the "mistake"... jackinnj or heybrook?
fwiw -- these are mid-1980's era HB2's -- the tweeter appears to be of an Audax HD12X9D25 variety.
Svante said:
Without accusing anybody of anything (which was probably out of line and I apologize) is 1% really of no consiquence at all? It seems to me that differences in the DRC of the bass inductor can account of as little as 1% or 2% of the speaker impedance and people make quite a big deal over that.
I guess I just always error on the "maybe they know something I dont" side (of course I know much less than most of you about this subject so perhapse that would explain it 😉 ) instead of assuming that the product was produced or designed "wrong". Is there no way this was an intended addition in the crossover?
-Chad
Maybe they had some concept of total group delay and its impact on natural reproduction or something. On the other hand maybe it was some real ale factor indeed!
Ok... now sombody will have to do some more explaining for me to understand. Here is the GD of the tweeter (woofer did not change significantly with the circuit):
The one with more group delay in the lower frequencies (red) is WITH the enigma circuit in place and the lower one (green) is without. Is this like an electrical offset for the tweeter (instead of physicaly offseting them)? Or am I missing the boat again? Perhapse we can actualy figure this out now
.
-Chad
An externally hosted image should be here but it was not working when we last tested it.
The one with more group delay in the lower frequencies (red) is WITH the enigma circuit in place and the lower one (green) is without. Is this like an electrical offset for the tweeter (instead of physicaly offseting them)? Or am I missing the boat again? Perhapse we can actualy figure this out now
.-Chad
Hi,
Heybrook was a small firm and probably outsourced manafacturing.
A lot of the smaller companies on the way of going out of business
took some severe liberties with QC and manafacturing standards.
One company I know had the speakers put together by the people
building the boxes, who knew absolutely nothing about electronics.
I suspect something similar.
But 1.9khz is typically twice the typical Fs of that tweeter ......
One thing for sure the Audax does have a large resonant peak,
which due to ferrofluid you don't see so often nowadays.
🙂/sreten.
http://www.audax.fr/audaxdoc.htm
P.S. I'm also assuming those circuit simulations are garbage,
whats a standard 4th order target got to do with 3rd order electrical ?
If your not discussing final acoustic responses your not really discussing anything.
Without full electrical models of the drivers electrical discussions are meaningless.
Heybrook was a small firm and probably outsourced manafacturing.
A lot of the smaller companies on the way of going out of business
took some severe liberties with QC and manafacturing standards.
One company I know had the speakers put together by the people
building the boxes, who knew absolutely nothing about electronics.
I suspect something similar.
But 1.9khz is typically twice the typical Fs of that tweeter ......
One thing for sure the Audax does have a large resonant peak,
which due to ferrofluid you don't see so often nowadays.
🙂/sreten.
http://www.audax.fr/audaxdoc.htm
P.S. I'm also assuming those circuit simulations are garbage,
whats a standard 4th order target got to do with 3rd order electrical ?
If your not discussing final acoustic responses your not really discussing anything.
Without full electrical models of the drivers electrical discussions are meaningless.
Well, you're wrong!
My HB2's have the same connection, and I can't understand the logic of it either.
They were designed by Peter Comeau, who until recently worked for Mission, and designed the e-series speakers. He is a very talented designer, all of the early Heybrooks, HB1, HB2, HB3 are excellent speakers.
My HB2's have the same connection, and I can't understand the logic of it either.
They were designed by Peter Comeau, who until recently worked for Mission, and designed the e-series speakers. He is a very talented designer, all of the early Heybrooks, HB1, HB2, HB3 are excellent speakers.