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The most fiddly tweak regarding a DIY loudspeaker project is determining a satisfactory tweeter L-pad configuration. I've spent numerous hours over the years fine tuning crossovers by soldering, desoldering, resoldering various resistors in order to determine proper attenuation levels, to my ear. Since a current DIY loudspeaker project I'm working on is a relatively non-critical-listening digital CATV audio application, I decided to literally think outside the box by mounting two pairs of binding posts sideways above the main ETI Cable Pod binding posts to easily connect and disconnect any given set of L-pad resistors, then quickly swap them out with another set if desired. I'll start with 3 different sets of L-pad resistors to choose from, with little concern if yet another set might be required to test. The sets of binding posts for the L-pad is a relatively high-quality Taiwanese-made surface-mount Parts Express #260-302, that only requires two small holes to be drilled through the back panel of an enclosure in order to connect the internal wiring.
This is the most straightforward point-to-point wiring scheme for the external L-pad used for a simple 1st order high-pass section.
What part of my replay didn't you understand?
The standard resistor values are never close enough.
Run the wire out to an L-pad and do it right.
In favor of more accurate loudspeaker design measurements, most modern loudspeakers don't feature a variable fixed-output switch for adjusting the attenuation-level of a tweeter to one's own taste, application, components, listening environment. A relatively non-critical-listening digital CATV audio loudspeaker application can benefit from user-changeable high-frequency energy output settings, since the audio source is comparatively Mid-Fi with a level of harsh treble characteristics, and since the tweeter for the project is intended as treble augmentation, being able to swap-out various resistor values, as well as various make/model resistors for attenuating treble energy to my own taste is desirable. The subject of my thread is a valid topic to post in Tweakers' Asylum about a custom L-pad configuration.
I hear you saying you want some sort of tone control or program equalizer.
Fine, but I would rather see it done ahead of the amplifier.
Tests have shown that the level of the HF with respect to the LF need to be within ±0.25dB to sound the most coherent. A change of ±0.25dB is plainly audible, the sound described as going 'out-of-focus', the listeners usually unable to tell you if the level was shifted 0.25dB too high, or 0.25dB too low.
A 0.25dB 12-position attenuator was used in these tests.
Snell used slide-bar resistors and allowed about 20 minutes for each speaker coming off the line.
I see your point, but it is not something I would ever do.
Snell used nasty sounding potentiometers in both the E-III's and C-IV's I used to own, FWIW.
It's not something I would ever do for a serious critical-listening application, either. The application is very specialized, in that the small stand-mount loudspeakers are intended to be used between the hours of 10 PM - 8 AM mainly for television viewing so as not to disturb others during quiet time. So clear dialog, subdued treble energy, and no lower bass to speak of is exactly what I want for the purpose. Pretty much a glorified midrange chamber, with an inexpensive 4" Dayton aluminum cone full-range driver and an AMT tweeter with a 1st order slope at 13kHz for improved off-axis dispersion and clarity. The stereo power amplifier is a Lexicon NT 212 (Bryston 3B-ST). BTW, I just terminated a pair of inexpensive AudioQuest FLX-16/4 speaker cables with CMC CMC-6005-CU-R bare copper spades for the nighttime configuration, and the speaker cables sound excellent for the application, even without burn-in, so things can only get better after proper burn-in time.
The "nighttime configuration" is the second "assisted single driver" design with an AMT tweeter for treble augmentation DIY project I've built. It's a fun project to configure for the specialized task; it also sounds nice as a satellite speaker for a computer multimedia application when used with a subwoofer with good slam. However, the computer workstation DIY project features a different full-range driver with higher sensitivity, so no L-pad resistors are required for that build. It's nice to only use a single cap or single cap with bypass, with no inductors, resistors, notch filters, et al. involved. I find high-performance internal wiring and binding posts are a must-have, as well as effective vibration control footers so the small enclosures can "sing" when positioned on rigid metal speaker stands.
I use an actual L-pad to balance out the speaker, then measure the values required, them build composite resistors (as the exact values required are never available).
Use the closet (larger) value, and parallel it with a value about 10x larger to trim it down to the exact value required (as measured).
I find the driver levels need to be matched within ±0.25dB, and standard values won't get you there.
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