Suitable replacement for BX63A?

[Riley Casey]

Connecting a DVM to the speaker terminals simply tells you that there's a coil of wire in there, reassuring but not terribly useful. If you want to ascertain that the woofer is doing something useful install a copy of AudioTools on your smart phone ( https://www.studiosixdigital.com/aud...ools-platform/ ) or acquire some other way of generating sine waves and sweep a tone from the lowest frequency your woofer is designed to produce to about an octave above the highest frequency of interest. Does it sound clean and undistorted? Does the level vary substantially from start to end? Thats the beginning of the process. To evaluate further download a copy of REW and RTFM on how to measure the impedance curve of the woofer. Impedance is what the woofer presents to the driving voltage of the amplifier and constitutes the valuable information. Resistance is what the DVM measures and does not constitute valuable information.

Alrighty. So, hook my multimeter up to the woofer and check resistance as I push the cone in? How much deviation from 8ohms is acceptable? (EDIT: just saw the spec sheet for the 2245H, 7.1ohms +/-10% @ 25 degrees C is the minimum acceptable impedance.)

Thank you for the input, I appreciate it.

[Riley Casey]

Aside from the silly stuff like the .5db 100 step attenuator thats a pretty good description of the old BSS FDS360 crossover.

Edited

I shared a few thoughts with Derek on a potential (new) replacement of the original BX63

...

[Ian Mackenzie]

Aside from the silly stuff like the .5db 100 step attenuator thats a pretty good description of the old BSS FDS360 crossover.

If you can find one.

Incidentally the above unit requires a technical understanding of how to modify the internal card circuits while closely following a detailed user manual. A PA engineer is more likely to use the above.

In my own market research and market testing that is not what a plug and make it go hifi user or a thinking cap user want or enjoy using. They much prefer front panel control interaction where the unit is has switchable pre set modes or configurations that have been engineered and tested to function correctly in the user scenario. Diy users get lost going down rabbit holes that as a rule they have no familiarity with or understanding of.

So it’s not what this is.

Technically the design expertise is drawn from consulting with Douglas Self a UK audio electronics designer, author and consultant who was formerly head of engineering at Soundcraft for a long time. Self’s research and systematic problem approach has influenced the design of high quality analogue audio equipment today.

The application of electronically controlled precision matched attenuation is straight forward.

Modern preamps incorporate these types of attenuation with a visual display. This is particularly important to the user when dialing in an active system where precision matching of all outputs is required. Multiple outputs can be controlled simultaneously.

The point is if you’re just turning a knob how the hell do you know how much you have attenuated the signal? If you change it again where are you then? Markings on panels are not necessary accurate nor is the tracking of a multi gang potentiometer.

A precision potentiometer with a visual display far more effective in this situation.

Jbl use 0.5 db switched L pad on their premium loudspeakers. Fractional attenuation over a broad frequency range is audible when relative to an adjacent broad frequency range.

A concept diagram of what l have proposed is attached
In summary such a device will provide:

- a mode for sub woofer EQ with a high pass filter and an adjustable two way subwoofer
crossover to a main loudspeaker system
- alternate crossover options for a helper woofer configuration or a diy project
- an alternative mode for main loudspeaker system LF EQ
- balanced / unbalanced input
- electronic ground compensated unbalanced outputs
- balanced outputs

[Ian Mackenzie]

This is an interesting unit but the price is silly 🤪

https://www.bhphotovideo.com/c/produ...SABEgI1wPD_BwE

[Riley Casey]

TBH this is where a DSP implementation shines as all of this functionality can simply be one of many presets. Conceivably one could implement a digitally controlled analog device for the diehards a la the venerable BSS Varicurve but the market for such would be minuscule.

If you can find one.

...

- a mode for sub woofer EQ with a high pass filter and an adjustable two way subwoofer
crossover to a main loudspeaker system
- alternate crossover options for a helper woofer configuration or a diy project
- an alternative mode for main loudspeaker system LF EQ
- balanced / unbalanced input
- electronic ground compensated unbalanced outputs
- balanced outputs

[Ian Mackenzie]

I agree in principle.

But a dsp hyprid processor using another Y connector out of an analogue preamp?

My thinking at the time was build a better mouse trap. Back when the BX63 was conceived it was very much all about analogue consumer audio equipment. But like all things they have a useful product life. The B380 and B460 drivers were associated with a do it yourself article in a hifi publication by Lor Kramer and Greg Timbers.

So as a concept it’s got some potential for someone looking for an updated version of a BX63A that does exactly the same job with a few more features. Audio types and in particular thinking cap hifi types are a funny bunch. They will believe what ever they are told of it makes their precious record collection sound better. But the twist is they are equally precious about anything that might detract from the sound they like. This is why selling a digital hifi amp (not a home theatre amp) in a hifi shop isn’t done. So if your plugging a digital dsp processor in the output of their wonderful valve Audio Research analogue preamp it’s a sin. Even talking about adding a sub woofer to an audiophile and they are skeptics.

But they know their loudspeaker could do with a gentle nudge in the bass. But what preamp has a bass and treble tone control these days?

So a completely transparent analogue device which can put a smile on their faces has a place.

This what happens when you get out in the field and meet the users. It’s no longer a technology or product driven conversation. It’s about listening & understanding the user and their needs.