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vuducchinh
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14-04-15
10:42:24
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vuducchinh
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14-04-15
10:41:41
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penndan
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09-04-20
22:15:09
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penndan
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09-04-20
21:57:44
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penndan
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09-04-20
21:56:23
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penndan
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09-04-20
21:39:26
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penndan
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09-04-20
21:11:59
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Neutrino88
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09-04-20
09:47:17
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TaiMonSing
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09-04-20
09:24:21
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Neutrino88
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09-04-20
06:58:33
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penndan
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09-04-19
23:02:57
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penndan
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09-04-19
22:42:00
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| 回覆 (11): Crossover designing |
two point frequency designing performance is best the mono point
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love to hear that.
Hope to see the photo of the cure soon.
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penndan
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09-04-19
22:35:31
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| 回覆 (12): Crossover designing (mid driver by -14db ) |
attenuator
the best is H
H is balance type
other is t type & pi type
t type & pi type are un-balance type
L type is not good for impedance matching network,
linearly problems,
affecting the sound quality is resistor material.
a good attenuator is must with out "industance and reactance"
and keep good linearly
in the rule (the input & output impedance is ohm+/- 0 degree no phase shift with in audio frequency response)
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Hi 300B_123 兄 ,
I ask this question,because I found to cut down -7db of the horn is still acceptable but more than that the horn will start to sound worse and worse.
The cut don of -14db is unbelievable to me. |
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penndan
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09-04-19
22:32:42
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Neutrino88
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09-04-19
05:09:16
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300b_123
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09-04-19
02:13:55
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| 回覆 (10): Crossover designing |
Your attached circuit diagram is a 4th order design,but in ordinary 4th order crossover L1 and L2 are in different mH and C1 and C2 are in different uf.Why yours is so different?
You asking this, yes!
at today is not much engineer to know filter network why!
"L1 and L2 are in different mH and C1 and C2 are in different uf"
this crossover is one point frequency design.
"L1 and L2 are in same mH and C1 and C2 are in same uf"
this crossover is two point frequency designing,
two point frequency designing performance is best the mono point
mono point frequency in easy calculation easy designing
two point frequency designing need more complex calculation.
I will post the photo
this curve show out two point frequency and single point frequency is why!
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300b_123
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09-04-19
02:02:14
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| 回覆 (11): Crossover designing (mid driver by -14db ) |
All the mid driver's gain is high than low driver
so, mid and high driver must need attenuate circuit (cuting down the spl level) to matching with woofer driver, keep the out put level is flat on frequency response.
attenuator
the best is H
H is balance type
other is t type & pi type
t type & pi type are un-balance type
L type is not good for impedance matching network,
linearly problems,
affecting the sound quality is resistor material.
a good attenuator is must with out "industance and reactance"
and keep good linearly
in the rule (the input & output impedance is ohm+/- 0 degree no phase shift with in audio frequency response)
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300b_123
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09-04-19
01:40:56
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| 回覆 (10): Crossover designing |
Hi penndan
2nd order and 4th order are 0 degree design
3 rd and 5th are +90,+180 or -90,-180 degree design
see what driver is matching
each order is -6db in frequency slop
also each order power gain loss from -0.5dB to -6db
4th crossover is -24dB slop is good than 2nd crossover,
because 2nd crossover only -12db slop
when the junction frequency betwween crossing point is C# 440Hz.
this signal output belong to 'low " woofer or "mid" horn?
2nd order -12dB will two drive " Low and mid" have sound (10watt reference testing)
4th order -24dB only the "low " driver have sond, the "mid" driver is no sound.
on hearing this is one point sound and no phase shift peoblems ,
When two difference driver have sound come out also create sound phase shift on air and phase distortion,
crossover design major is each frequency only one part have sound output,
other part is near off condition.
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300b_123
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09-04-19
01:06:57
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| 回覆 (9): Crossover designing |
Hi 300B_123 兄 ,
thank you for open suck a wonderful thread.I'm interest in this thread very much.
A) I heard of betterworth 2nd order crossover but not for 4th order.Would you mind to explain a little bit why 4th order design was chosen to build?
B) Also, do you have any experience to share about building a Altec A5 (single woofer) and A4 (double woofer) crossover?
C) What is the method you use to attenuate the mid driver by -14db without affecting the sound quality of mid.
D) Your attached circuit diagram is a 4th order design,but in ordinary 4th order crossover L1 and L2 are in different mH and C1 and C2 are in different uf.Why yours is so different?
thanks! |
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penndan
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09-04-18
20:38:48
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300b_123
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09-04-15
00:47:34
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kris
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09-04-14
09:06:05
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300b_123
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09-04-14
02:06:22
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300b_123
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09-04-14
01:51:24
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300b_123
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09-04-14
01:50:17
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| 回覆 (3): Crossover designing |
The 3 way crossover
Low frequency is JBL 1405
Mid frequency is JBL 2451
High frequenccy is JBL 2405
Low frequency is 96db at 1watt at 1 meter
mid frequency is 110db at 1watt at 1 meter
high frequency is 105db at 1watt at 1 meter
driver brand coverage ( 96dB spl level)
Low frequency from 33Hz to 510Hz
mid frequency from 510Hz to is 8,200Hz
high frequency from 8,200Hz to 21,000Hz
Driver att T network
Low frequency 96dB
mid frequency (-14dB )
high frequency (-10dB)
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Coil specification
L1 & L2
wire 3.26mm Dia
2.62 mH
Q=13
DC resistance > 0.35 ohm
L3 & L4
wire 3.26mm Dia
1.55mH
Q=24
DC resistance > 0.25 ohm
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Capacitor specification
L5 & L6
wire 2.1mm Dia
100uh
Q=33
DC resistance > 0.22 ohm
C1 & C2
45uf X2 =90uf
45uf test conditidon
7.59 ohm at 120Hz
dissipation factor =0.218
C3 & C4
24uf
1.74 ohm at 1000Hz
dissipation factor =0.264
C5 & C6
2.2uf
16.9 ohm at 1000Hz
dissipation factor =0.237
--------------------------------------------------
coil photo
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300b_123
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09-04-14
01:49:00
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300b_123
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09-04-14
01:21:28
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300b_123
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09-04-14
01:20:31
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300b_123
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09-04-14
01:01:22
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