Need help modifying BW 603S2 crossover

[Deleted member 49736]

This is the HF/MF crossover from a B&W 603 S2. I need to recreate this crossover without a bandpass on the midrange. I only need a low pass for the midrange. I’d like to keep the point and slope between the mid and tweeter the same. I know absolutely nothing about passive x-overs and any online calculators have been zero help.

I completely eliminated the LF crossover and I’m using a MiniDSP SHD to create an active bandpass filter for the dual 6.5s. Huge boost in performance. Currently using an Elan Z660 Amp (planning to upgrade to a VTV 4ch NC500OEM or Purifi 1ET400a).

 

[AnalogSteph]

Found a crossover schematic:
1.200 × 1.621

Looks like you'd have to unsolder one end of the smaller 0.7 µH coil and short out the 47µ capacitor.

A 1st order highpass on the tweeter is pretty naff.

 

[Deleted member 49736]

Wow, thanks! Let’s say I wanted a 2nd order LR highpass on the tweeter, low pass on the mid…what would I need to change?

 

[Deleted member 49736]

I figured it out. I’m shocked the x-over is 4225. I’m going to have to disconnect the mid and tw independently and measure them with REW to determine if I should change to a lower x-over point.

 

[digitalfrost]

You cannot calculate this. Like you can but it won't help you in the real world. Speakers impedance won't be a single value and the effects of the frequency reponse and baffle step will not be taken into account by any calculator.

 

[Deleted member 49736]

You cannot calculate this. Like you can but it won't help you in the real world. Speakers impedance won't be a single value and the effects of the frequency reponse and baffle step will not be taken into account by any calculator.

Sounds like I’m stuck with the circuit B&W developed unless I want to have the tweeter and midrange analyzed for impedance vs response.

 

[Deleted member 49736]

That same website also has this schematic for the 606 S2. Different cap on the tweeter, still 1st order. Totally different midrange, the only clear cut similarities are the continuum cone and diameter, they’re different part numbers. Does this offer any more insight to aid in developing a 2nd order crossover for my situation?

 

[thewas]

View attachment 217514That same website also has this schematic for the 606 S2. Different cap on the tweeter, still 1st order. Totally different midrange, the only clear cut similarities are the continuum cone and diameter, they’re different part numbers. Does this offer any more insight to aid in developing a 2nd order crossover for my situation?

That scheme seems to be incomplete as there are more components on the crossover they show https://www.avmagazine.it/articoli/audio/1469/03.jpg

Funnily a German review shows a different crossover photo which possibly is from a 3-way model https://www.bwgroup.ch/wp-content/u...-606-S2-Anniversary-Edition-Audio-2020-12.pdf

 

[alex-z]

If you have gone to the trouble of removing the low frequency crossover and are running a miniDSP setup, you might as well finish the job and go full active.

miniDSP 2x4HD per speaker, TPA3255 amp for the mid-range + tweeter, maybe an Outlaw 2220 monoblock for the woofers.

miniDSP 2x4 HD

MiniDSP 2x4 HD, a USB DAC+DSP in a low cost package powered by a powerful Sharc 400MHz floating point DSP. The upgraded on-board 400 MHz Analog Devices SHARC processor also ena-bles substantial processing upgrades previously available only on more ex-pensive platforms, such as 96 kHz internal...

www.minidsp.com

https://www.amazon.com/AIYIMA-A07-TPA3255-Amplifier-Digital/dp/B08CJZGT6H

Model 2220

Mono? Mini? Micro? Magnificent? Whatever that M is, this is one UNREAL little single-channel amp. 200 Watts (conservatively!) into a 3-inch chassis with balanced input stage to offer Common Mode Rejection! MANUAL See Front Panel Huge See Rear Panel Huge

outlawaudio.com

$655 per speaker to go from the stock corner cutting passive crossover to a fully active setup with lower distortion, higher efficiency, and better directivity control. Active designs are easier for beginners to work with, you can rapidly try different settings without the cost of new passive parts.

 

[Deleted member 49736]

If you have gone to the trouble of removing the low frequency crossover and are running a miniDSP setup, you might as well finish the job and go full active.

1. I need to use an SHD because I use Volumio for input selection and volume control through my home automation system.
2. Full digital signal path can not be maintained with two 2x4HDs on their own. This would require a SHD, SHD Studio, or Flex (Digital) ahead of the 2X4HDs. The SHD has a far superior DAC than the 2x4HD. The SHD has balanced outputs. The 4x10HD is a better solution than a pair of 2x4HDs. The SHD line is the only option to run Dirac at 96kHz.
3. Dirac fixes 99% of the problems anyways. The speakers already sound fantastic with Dirac and unmodified crossovers.
4. A pair of new HF/MF crossovers will be about $100, using higher quality or equal components than the original crossovers. I could modify the original crossovers in about 15 minutes with about $2 worth of OFC 14awg.
5. I do not want to modify the cabinet to add a 3rd set of binding posts. I’m not taking a saw to my speakers. I considered trying to have new binding post/port plates 3D printed to fit the factory openings. Decided it’s not worth the time or money. Because…
6. There’s much more to gain by eliminating lower frequency passive crossovers than the higher frequency crossovers. Given the ridiculous amount of extre effort it would require, and the potential to yield little to no benefit, eliminating the ~4kHz 1st order butterworth crossover between the mid and tweeter is not worth it.

 

[Deleted member 49736]

That scheme seems to be incomplete as there are more components on the crossover they show https://www.avmagazine.it/articoli/audio/1469/03.jpg

Funnily a German review shows a different crossover photo which possibly is from a 3-way model https://www.bwgroup.ch/wp-content/u...-606-S2-Anniversary-Edition-Audio-2020-12.pdf

It doesn’t look incomplete to me? What components do you see that are missing?

I believe that’s a picture of a 603 S2 HF/MF crossover, but the 2 small caps are white instead of black like the picture I found.

 

[thewas]

It doesn’t look incomplete to me? What components do you see that are missing?

The little blue capacitor almost fully hidden on the left side under the cable:

 

[Deleted member 49736]

This is the circuit I'm going with for the midrange low pass. Anybody have parts suggestions?

-board
-6.8ohm Resistor
-1.0mH Inductor
-10uF Capacitor
-4.7uF Capacitor

 

[Deleted member 49736]

The little blue capacitor almost fully hidden on the left side under the cable:

I believe that's a resistor. Looks like the schematic for the 603 x-over is also missing 1 resistor. There's 3 in the photo and 2 on the schematic. At least there's a pattern...

 

[LTig]

I believe that's a resistor.

IMV your believe is false.

 

[Deleted member 49736]

IMV your believe is false.

In any case there’s absent components on both schematics, passive crossovers are a grotesque inconvenience and there’s a lot of very knowledgeable yet unhelpful people, and vice versa, on the internet

 

[AnalogSteph]

The little blue caps seem to be labeled 104 = 10n. Possibly "spoof" components to make the circuit appear more complex, at least I can't see them doing anything major.