Mar 5th, 2010
We are very experienced in the repair and modification of this crossover. Our modification upgrades the power handling of the speaker to accommodate 100watt amps and the dynamic range of CD, improves fidelity, phase response and correctness, and allows the speaker to output stronger bass. We replace or add on certain crucial value capacitors and resistors to correct the midrange sound to be equal to the woofer and tweeter. We also “sharpen” the crossover (technically, a 12dB per octave crossover) to the tweeter and midrange to prevent overdrive failures and increase spatial clarity and image. ADS speakers (as well as many others) were designed in an era when 30 to 40 watt amplifiers were typical and the source material was cassette tape or vinyl. Now people often use 100 watt amplifiers in their homes, and the dynamic range of CD is much greater than analog sources. ADS voiced the speakers for a very pronounced midrange output to allow voice and instruments to be brighter and bolder, but by today’s standards it is too much and often causes driver failures when played loudly. We also check and replace the electrolytic capacitors, as many will have aged off of spec and need to be replaced. We add or replace eight to twelve parts per board using matched spec mylar capacitors and other audiophile grade parts. After years of working on these speakers, we have also noticed a problem of subtly mismatched crossover boards; we will make them identical between the two speakers. $220 includes all parts, labor, and return shipping to modify one pair of crossover boards. You may send us just the boards, as it is not difficult to (carefully!) remove the crossover boards and connectors out of the speakers.
In fact, nearly all ADS 3-way speakers with the round dome midrange design share the same crossover board. Models with a double woofer or single 8-inch or 6-inch woofers use virtually identical circuits. This is why, for instance, a Model 1290 with two 8-inch woofers would require a variation of the crossover update to reduce the midrange level by about 4dB, while in a single woofer design the midrange level will be reduced by almost 6dB.
ADS speaker products used quality parts, still competitive with today’s parts. Modern speakers may be more efficient and play a little louder or with more intense bass, but the crucial design parameter which makes a speaker likeable is the driver (woofer, mid, tweeter) “dynamic linearity” spec. This describes the ability of the drivers to have similar audio output at low, medium, or high listening levels. Another way to say this is that at high or low sound levels the sense of bass and treble balance remains constant. Although the midrange obviously runs much louder in the original design, its dynamic linearity is similar to the woofer and tweeter. The correction of phase and sound output level of the midrange will allow equal output at any playing loudness. The modified ADS crossover will effectively create a sense of a “coherent” output whereby the ear does not notice one driver dominating the sound stage. Now a seamless tonal balance of timbre allows a more honest representation of any recorded music.
Owners should also note that the voice coil alignments can get a little bit off center with aging, causing a woofer to rattle or a midrange or tweeter to sound fuzzy or less dynamic. These problems can be resolved by careful adjustment of the face plate mounting screws. Please call us here directly for more information on this matter.
Inquire about this Modification