I found two loudspeakers that are three-way configuration have the same drivers except woofers and enclosures: ADS L980/2 and L1590/2. Despite the same mids and tweeters, their crossovers on mids and tweeters are different.
However, there exists similar situation in the previous series: ADS L810 and L1230. The L810 and L1230 have exactly the same ALL drivers and crossovers, and only EXCEPT the cabinets.
Back to the L980/2 and L1590/2, the crossovers are simply second-order on both high-pass and low-pass section.
The component values are different as follows:
L980/2: C1 = 4.7uF, L1 = 0.3mH, C2 = 13.6uF, L2 = 0.6mH
L1590/2: C1 = 6.8uF, L1 = 0.2mH, C2 = 15uF, L2 = 0.4mH
I’ve already put these values into simulation software, VituixCAD2, to see their filter’s characteristics. It showed the L1590/2 has peaky SPL response at the crossover region, whereas the L980/2 has smaller peak there.
I wonder why they were designed different mid-to-high crossovers, unlike the other case mentioned above—L810 and L1230. Is it because the baffle diffraction theory? AFAIK, the baffle diffraction would affect in the low frequency region, i.e., the woofer and cabinet interaction. So, they might be able to use the same crossovers (for mid-to-high), weren’t they?
PS. JBL L112 and L96 also use the same crossovers despite the different components including drivers, cabinet dimension and baffle size.
However, there exists similar situation in the previous series: ADS L810 and L1230. The L810 and L1230 have exactly the same ALL drivers and crossovers, and only EXCEPT the cabinets.
Back to the L980/2 and L1590/2, the crossovers are simply second-order on both high-pass and low-pass section.
The component values are different as follows:
L980/2: C1 = 4.7uF, L1 = 0.3mH, C2 = 13.6uF, L2 = 0.6mH
L1590/2: C1 = 6.8uF, L1 = 0.2mH, C2 = 15uF, L2 = 0.4mH
I’ve already put these values into simulation software, VituixCAD2, to see their filter’s characteristics. It showed the L1590/2 has peaky SPL response at the crossover region, whereas the L980/2 has smaller peak there.
I wonder why they were designed different mid-to-high crossovers, unlike the other case mentioned above—L810 and L1230. Is it because the baffle diffraction theory? AFAIK, the baffle diffraction would affect in the low frequency region, i.e., the woofer and cabinet interaction. So, they might be able to use the same crossovers (for mid-to-high), weren’t they?
PS. JBL L112 and L96 also use the same crossovers despite the different components including drivers, cabinet dimension and baffle size.
Specifications list 550Hz mid crossover for the ADS L980, 350Hz for the L1590, your crossover does not show a high pass for the mid driver, it couldn't survive without, so the circuit diagram is not complete.
Did you use the actual impedance curves for each driver in your simulation?
Specifications list a 5000Hz high crossover point and 8 ohm, what crossover point did your simulation show?
Also says the ADS L980 was made 1983-1986, the thinner L1590 made in 1986, a different "voicing" might have been desired, or they decided to go with cheaper (less copper..) coils and make up the difference with larger caps...
Anyway, conjecture about 38 year old incomplete crossover circuits is a "who knows" venture 😉
Sorry, the missing high pass for the mid driver is the same for both models that is C = 33uF and L = 2.6mH in traditional second order high pass configuration.
No, I use resistive loads. Since there's no impedance equalization anywhere, I believe the impedance at crossover region might be linear. So I assume they are resistive with 4 Ohms for tweeter and 6 Ohms for midrange.
Attached are simulations of the crossovers of both L980/2 and L1590/2.
Attachments
You might gain more information on this if you use polars in vituixcad and look at power. It is quite a difference, however. Do they sound like they're voiced differently?
Yes, AFAIK, the 980s were designed for studio monitor used while the 1590s were designed for home used.
I also used to convert my 1590’s crossovers to the 980's, but I've now restored them back to the original. I found that they’re voiced differently. The 980’s were a bit softer and more polite, whereas the 1590’s had a stronger, more pronounced, and more open voice.
That forward midrange might help sell units, but I'm sure some of us would choose to dial it back.
That begs the question of whether the difference is mostly equalisable voicing, or whether the cross itself is different the way we do blending these days. I'd say the first. The voicing would have been done that way because it was the only practical way. You could (and probably should) voice to your own liking, and while you're there manage the room a little within the confines.
That begs the question of whether the difference is mostly equalisable voicing, or whether the cross itself is different the way we do blending these days. I'd say the first. The voicing would have been done that way because it was the only practical way. You could (and probably should) voice to your own liking, and while you're there manage the room a little within the confines.
Sim looks close to ~350Hz for the L1590, but the mid crossover for the ADS L980 was listed at 500 Hz.
Seems unlikely the two 10" would have the same impedance curve as the 12".
The 2ohm series resistor should make a six ohm mid near 8ohm.
The high crossover was listed at 5000Hz high and the speaker impedance at 8 ohm, your sim comes in ~3.15kHz, with the tweeter level hotter than the midrange.
Why do you assume a resistive 4 Ohm tweeter?
Actually, the 980’s mid-to-low crossover point is listed at 450Hz regarding the spec sheet.
In the schematic document I used for the simulation, it listed the tweeter’s resistance (Re) of 3 Ohms. So I conjectured the tweeter’s impedance might be about 4 Ohms.
Yes, but as mentioned earlier in the original post, I found the JBL L112 and L96 also had similar situation—10” vs 12” woofer with the same crossover. So, I understood it might be able to be compromised.
ADS seems to be as you mentioned, in practice.