Speaker sensitivity vs SQ

Most speakers of low sensitivity have more elaborate crossovers to even out the frequency response.  It is just an engineering tradeoff, but since more power is needed, anyway, better drivers, also of low sensitivity can be used.  When I switched from a 200 wpc Phase Linear amp pushing stacked Advents, I was in heaven, at least until I heard a Threshold amp and Audire amp drive really good speakers,

@mijostyn --

Just looked over at your profile, and you have an impressive set-up from what I can assess (haven’t heard it, obviously, but I’m sure it’s sonically extremely capable). You wrote "Sound Labs" being your main ESL’s, but the profile reads Acoustat’s - which is it? A friend of mine have a pair of older Acoustat’s, smaller than yours (can’t remember the model number), and they’re very coherent sounding, transparent and informative. Having a single transducer cover the entire range from 100-20kHz is an impressive, and not least an important feat when done well; being ESL’s I can only imagine that it is. Moreover being a line source (as such) from floor to ceiling adds to their traits.

Personally and over time I’ve never been fully convinced or taken the type of presentation from the line sources I’ve heard, but as executed in your case, with subs augmentation and the ESL’s relieved below 100Hz to boot, I may feel differently about it. You don’t shy away from cone area with the subs either, and with lots of power at hand from your QSC’s bodes well for headroom and clean bass. Have you tried spreading out your subs DBA-style? Not meant as an advocation of mine, but just curious what you’ve come to find here, in case.

I can certainly relate to where you’re getting at with your set-up imagining a large, enveloping and coherent sound field that’s fairly uninhibited LF-wise as well. It’s not at all unlike what I’m after, though quite obviously very differently executed.

@johnk --

Community made the best horn designs even today we haven’t equaled what they offered during the 1970s. Their multi cells are by far the most advanced on earth the leviathan and the radials all not bettered by modern designs. I have been beta testing for a few companies they know I have many horn types to use the horns they made to go with there new designs are just based on older designs but are smaller. So while it is possible to design better horns today we don’t because of the size and costs to build them.

It’s the recurring roadblock for sound reproduction in a home environment: size. JMLC horns (with the proper calculated horn profiles, that aren’t mostly used) are great, I find, and don’t skimp on size. The upcoming bigger EV horns of mine (HP9040) mayn’t dance with the best, but I’d wager they bring about advantages (compared to smaller, more modern horns) precisely because of their size and controlling directivity as low as they do. Getting a closer coverage pattern match over the cross-over range arguably is one of the "macro parameters," and being successful seeking out and attaining others as well is what it’s about, basically - to me, at least. Size restrictions keep one from hitting many of said parameters, but more than cost considerations it appears size itself (and the change in design narrative) is the primary obstacle.

My reply is intended to illustrate why & how some high performance speakers are purposely designed knowing that they will have to be low in efficiency because of the laws of physics and engineering. Mini-monitors, like the sealed BBC LS3/5a's and the rear vented KEF LS-50's which have fairly good bass, superb mids & highs but low overall efficiency (82db to 84db)  have obviously earned a prominent place in the market. While higher efficiency spkrs are the ideal it it's impossible to achieve both extended bass & high efficiency is small cabinets. Therefore, if you want a mini monitor to achieve bass the efficiency will have to be limited to about 82db to 85db. The smaller the speaker box, the lower the efficiency must be to avoid sounding thin. The laws of physics & engineering just can't be ignored.  But there are tricks to make it possible for small woofers to perform well in both the bass and midrange in small enclosures. The 1st is the use of small magnets which raises a woofer's Total Q factor(QTS) which partly determines the bass output consistent with Theile-Small equations. The 2nd trick is to increase the compliance of the woofer surround which lowers the woofer's resonance frequency. A 3rd way is to select high mass cones effectively raising the QTS and lowering the free air resonance frequency. A 4th method is to use crossovers that simultaneously tame the mid frequencies of the woofer so that they don't drown out the woofer's bass output and at the same time use woofer crossover inductors (coils) with a high enough measured DC resistance to raise the woofer's effective QTS. A 5th method in sealed boxes that accentuates bass but lowers efficiency is to judiciosly overstuff the cabinets with absorbent material eg fiberglas or polyester pillow stuffing which makes the woofer behave as if it's in a much larger box. The stuffing amount can be adjusted to change the QTC (the box's QT) ideally between ,707 and 1.0. A final thought...complex crossovers can be very helpful in compensating for imperfect woofers, tweeters, & mids but they lower overall efficiency and often tamp down dynamics. Obviously there's lots to consider.

My reply is intended to illustrate why & how some high performance speakers are purposely designed knowing that they will have to be low in efficiency because of the laws of physics and engineering. Mini-monitors, like the sealed BBC LS3/5a's and the rear vented KEF LS-50's which have fairly good bass, superb mids & highs but low overall efficiency (82db to 84db)  have obviously earned a prominent place in the market. While higher efficiency spkrs are the ideal it it's impossible to achieve both extended bass & high efficiency is small cabinets. Therefore, if you want a mini monitor to achieve bass the efficiency will have to be limited to about 82db to 85db. The smaller the speaker box, the lower the efficiency must be to avoid sounding thin. The laws of physics & engineering just can't be ignored.  But there are tricks to make it possible for small woofers to perform well in both the bass and midrange in small enclosures. The 1st is the use of small magnets which raises a woofer's Total Q factor(Qts) which partly determines the bass output consistent with Thiele-Small parameters. The 2nd trick is to increase the compliance of the woofer surround which lowers the woofer's resonance frequency. A 3rd way is to select high mass cones effectively raising the Qts and lowering the free air resonance frequency. A 4th method is to use crossovers that simultaneously tame the mid frequencies of the woofer so that they don't drown out the woofer's bass output and at the same time use woofer crossover inductors (coils) with a high enough measured DC resistance to raise the woofer's effective Qts. A 5th method in sealed boxes that accentuates bass but lowers efficiency is to judiciosly overstuff the cabinets with absorbent material eg fiberglas or polyester pillow stuffing which makes the woofer behave as if it's in a much larger box. The stuffing amount can be adjusted to change the Qtc (the box's Qt) ideally between .707 and 1.0. A final thought...complex crossovers can be very helpful in compensating for imperfect woofers, tweeters, & mids but they lower overall efficiency and often tamp down dynamics. Obviously there's lots to consider.

Hi @atmasphere ,

There are a lot of examples when amplifier has mixed SE and PP stages.
For example some SET amplifiers have first stage SRPP and PP amplifiers have SE first stage before phase spliter.
Another example - SE preamp and PP amplifiers.
Do all these amplithis have a prominent 5th harmonic in addition to a 2nd and a 3rd ?

Regards,
Alex.