Does impedance of a speaker change when one bi-amps?

I'm fairly new to the audiophile arena and i have seen this question asked before, but not answered.

rickytickytwo11-21-2018 3:06am

Showing 5 responses by bdp24

bdp24 Details Discussions Posts This discussion Message User 10,096 posts 11-27-2018 at 10:07am Copy Comment URL Report Comment Edit Delete There are companies offering DIY loudpseaker kits, the drivers and speaker-level passive x/o parts, along with required enclosure (or OB baffle) specs, provided. You make the enclosure (or buy one with the specified internal volume; Parts Express sells good ones) or OB baffle, and install the drivers and x/o. One such is Danny Richie at GR Research, located in Texas. He is a renown x/o designer, doing work for other speaker makers. Very high performance-to-cost-ratio speakers. Danny specializes in high-sensitivity designs (and is a fan of OB's) for use with low-power tube amps. Details on the GR Research website.
bdp24 Details Discussions Posts This discussion Message User 10,096 posts 11-26-2018 at 01:49pm Copy Comment URL Report Comment Edit Delete The current .7 series Maggies have series crossovers, and are therefore not candidates for bi-amping. The .6 and earlier have parallel crossovers, and can be bi-amped. An electronic x/o is used in place of the external one supplied by Magnepan with the 3.6, and the speaker benefits greatly from bi-amping. Not just for the benefits mentioned above (eliminating the possibility of amplifier IM distortion, etc.), but because instead of one, brute-force amp on all the speaker’s drivers (Maggies need lots of current), two smaller, perhaps better-sounding amps can be used. A ss on the bass panels, a tube on the mid/tweeter is a favorite combination, one I myself employ with my Tympani T-IVa’s. Some long-term Maggie user/owners have therefore chosen to stay with the older models (the .6 is a favorite), primarily to be able to bi-amp.
bdp24 Details Discussions Posts This discussion Message User 10,096 posts 11-24-2018 at 06:24am Copy Comment URL Report Comment Edit Delete The most interesting loudspeaker product I am aware of is Roger’s new Music Reference ESL loudspeaker/dedicated direct-drive OTL amplifier combination (a great idea, though audiophiles don’t like to have their amp dictated to them ;-). ESL transparency, speed, lack of coloration (unsurpassed vocal and instrumental timbre, texture, etc.), and all the other ESL attributes (okay, I love ESL’s!), and no input (step up) transformer. And driven by a dedicated, direct-drive OTL amp (no output transformer, the tubes connected right to the ESL panels). What could be more pure?! A powered sub is included, and since not a single other power amp or other electronic component is required or necessary, you just feed the system the signal of your choice. The combined price is less than that of the multi-driver/complex-crossover monstrosities reviewed in Stereophile every month. I’m saving up for my pair ;-) . There are companies making powered monitor loudspeakers for the pro sector (Westlake Audio, for one), but if you have heard any of them you know they aren’t exactly audiophile products, made for listening to music in the home. Sensitive and dynamic yes, but too colored, shouty, and coarse for me.
bdp24 Details Discussions Posts This discussion Message User 10,096 posts 11-24-2018 at 01:41am Copy Comment URL Report Comment Edit Delete Being able to get rid of the speaker-level crossover parts is one of the two reasons for bi-amping (doing so has at least the potential for producing a worthwhile improvement in the sound quality of a loudspeaker). The other is, as Roger Modjeski said above, to separate the low frequencies from the mids/highs in the amplification (giving each it’s own amp, of course), thereby decreasing the potential for the creation of IM distortion in the amp(s). Bi-amping need not be complicated and difficult. And, it can be cheaper than replacing stock speaker-level x/o parts with those pricey boutique ones. Not only that, you can use a brute-force amp on the woofers if you want, with a nice tube amp for the mids and highs. I first bi-amped with a pair of Magneplanar Tympani T-I loudspeakers in 1973, using the ARC passive x/o designed specifically for that task. Nelson Pass makes a great electronic x/o, but it’s not cheap. Fortunately he also makes (or made, it has just been discontinued) a modestly-priced 2-way x/o, the First Watt B4. It provides 1st/2nd/3rd/and 4th order filters in 25Hz increments from 25Hz to 3200Hz. All discrete (no opamps, no ic’s), retail price $1500. Reno Hi-Fi may have one left, I don’t know. For DIY’ers, it will soon be available as a kit.
bdp24 Details Discussions Posts This discussion Message User 10,096 posts 11-21-2018 at 07:16am Copy Comment URL Report Comment Edit Delete Beside the advantage of a bi-amped speaker presenting an impedance of less variation to each of the two power amps than one amp sees from a non-bi-amped speaker, the speaker’s drivers are also connected directly to the amps, not to the speaker’s internal crossover components. Bi-amping is usually (and best) done with an external electronic x/o before the two amps.

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