Do they exist (in analog form)?
I would like to be able to have two adjustments to fine tune the speaker to the filter as the speakers are new, and as they age the parameters may change.
Looking at the spreadsheet though it seems that to change the Q or the F3 of the speakers response in the filter requires changing all component values.
I would really like a filter which just flattens the response, not adding another Q and f3 lower down - and then have a separate filter to provide the low freq rolloff. Dont know how or if its possible though.
I would like to be able to have two adjustments to fine tune the speaker to the filter as the speakers are new, and as they age the parameters may change.
Looking at the spreadsheet though it seems that to change the Q or the F3 of the speakers response in the filter requires changing all component values.
I would really like a filter which just flattens the response, not adding another Q and f3 lower down - and then have a separate filter to provide the low freq rolloff. Dont know how or if its possible though.
Hi,
Your complicating matters, a peaking high pass filter does both and is simpler.
Its fairly easy to arrange the peaking (flattening) Q to be adjustable, but it
needs an initially overdamped response.
A LT unlike the above flattens an already peaking response, its quite complicated.
What functions you need depend on the driver and the box.
rgds, sreten.
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Im thinking of the LW transform - not a LW crossover filter. The transform (filter) cancells out the speakers Q and f3 and replaces them with new ones, lower and better - at least for a theroretically pure speaker.
I'm not wanting to use fixed value components in the LW Transform design as the speakers are new and may change over time with use, so I would like to be able to adjust for this - so I would want to adjust the Q and F3 that the transform cancells out. The new Q and F3 of the system does not need to be adjusted (unless I change my mind).
.
The pure Euclidean logic which underlies LT is really only the roughest guide to producing a good sounding installation (a) in your room and (b) in relation to Fletcher-Munson stuff. Such corrections, however compelling their logic are for connoisseurs of beautiful theoretical sound or as just general guidance for builders.
With the best theory, satisfying bass will still elude you until you do mic testing. So just have a flexible parametric EQ box on hand - even a single band, and old-time tone controls or loudness circuitry on your pre-amp will be very helpful.
We all love beautiful theories, no denying that.
Ben
With the best theory, satisfying bass will still elude you until you do mic testing. So just have a flexible parametric EQ box on hand - even a single band, and old-time tone controls or loudness circuitry on your pre-amp will be very helpful.
We all love beautiful theories, no denying that.
Ben
Years ago (about 20 - I must be getting old) equalisation was all very expensive but now I'm amazed at what is available in the DSP realm. $99 for minidsp and $150 for beriger feedback destroyer (can be programmed as a multiple parametric eq).
I'm going to use the minidsp in my car system and will probably get something like that for my HTPC - maybe just software. There's my adjustability problem solved.
Hi,
You generally don't start off by saying you need an LT circuit. That implies
all sorts of trade offs, with the driver and the presumably sealed box.
You wouldn't want the part of the LT than matches the in-box alignment
to be adjustable, parameters in box should not change much over time,
as the small box volume should dominate any suspension changes.
If you only compensate for the Fbox Qbox pair you will end up with
infinite gain at DC, the new 2nd order roll-off you add determines
the amount of bass boost applied, here it is 18dB : Active Filters
Your spreadsheet might adjust all the values, that is the way its written.
Want you want is one that uses a filter topology designed to be adjustable,
and that should only adjust the "new" Frolloff and Qrolloff.
Alas my maths are not up to the job.
rgds, sreten.
You generally don't start off by saying you need an LT circuit. That implies
all sorts of trade offs, with the driver and the presumably sealed box.
You wouldn't want the part of the LT than matches the in-box alignment
to be adjustable, parameters in box should not change much over time,
as the small box volume should dominate any suspension changes.
If you only compensate for the Fbox Qbox pair you will end up with
infinite gain at DC, the new 2nd order roll-off you add determines
the amount of bass boost applied, here it is 18dB : Active Filters
Your spreadsheet might adjust all the values, that is the way its written.
Want you want is one that uses a filter topology designed to be adjustable,
and that should only adjust the "new" Frolloff and Qrolloff.
Alas my maths are not up to the job.
rgds, sreten.
Last edited:
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