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In Reply to: RE: External L-pad Connections Wiring Scheme posted by Duster on June 13, 2017 at 19:42:49
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.
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.
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