[gary]

Almost two years ago now I bought a bunch of Perpetual Technologies gear from JohnB (P1-A, Modwright II P3-A, Monolith power plant). Since then I've added Revelation Audio silver power cords and I2S cable and an Onix Grandmaster digital interconnect, and it's sounded great, but what I've really been waiting for was speaker correction software for the P1-A & P3-A. That potential was the true value of the package.

This weekend I went to an AV123/Rocket get-together in Saratoga, NY where they were finally going to be demo'ing SOCS (speaker-only correction software) for the P1-A on Onix Reference 1 speakers, my own pair of Ref 1's in fact.

When I first arrived Mark Schifter of AV123 was demo'ing SOCS on the Rocket 750's. The difference was night-and-day, and as soon as I heard it I knew that something very "special" was happening. All of the phase distortion that I knew was there with those speakers (I owned them but upgraded to the Ref 1's for just this reason) simply melted away, and what was left was clarity. A pair of $1500 loudspeakers was doing something amazing, something that I hadn't heard any speaker do.

After a few minutes Steve Ozmai (also from AV123) and I had the Ref 1's set up, and we started listening. What I heard was profound, and all I'll say for now is that in my opinion it's only a matter of time before phase and frequency response correction is an integral part of every high-end audio system. Yes, it's that good... after hearing it, there's no way to go back. Even a system costing 10x what mine does would be lacking now to me, as hard as that probably is to believe. Luckily Mark was gracious enough to let me borrow the P1-A that had been loaded with Ref 1 SOCS, and I'll post some more thoughts on it in the near future after I've had some more time with it at home. Now, I just can't wait to get home from work and listen to it some more.

-Gary

[Mad DOg]

i seem to recall you asking me about the impact that SOCS would have on the Ref 1s awhile back...glad you've now experienced it for yourself! happy listening!

[BikeWNC]

I had the very same reaction to the TacT RCS 2.0 in had in my system.  I was immediately thrilled with the new found balance and clarity, especially in the mid to upper bass region.  Over time however, it began to sound artificial and only sounded at its best in one narrow listening position.  Every position in the room needed a separate correction filter to sound right.  I have since removed the RCS and am exploring the world of bass traps and acoustic treatments.  I hope to even the sound throughout the room such that little correction is needed in the first place.  Perhaps a combination of traps, treatments and room correction would render the best result.

Andy

[kana813]

Andy- I also use a TacT RCS, and don't find the improvements limited to one listen area. Maybe the additional processing power in 2.0S and 2.2X  creates a wider listening window than your 2.0.

I have also found that improving the unit's power supply, greatly opens up the soundstage and dynamics.

FYI- TacT is now selling direct and has lowered their pricing.  Aloha, Dan

[JoshK]

Andy,

The principle of Speaker correction is a whole different world than that of Room Correction.  Speaker correction accounts for time alignment deficiencies and phase misalignments that are inside the xo of the speaker.  Room correction is something completely different.

[JLM]

In case I haven't mentioned it enough...  

Single driver speakers have no time or phase alignment problems to start with and they also realize all the advantages of active speakers (the amp "sees" more clearly a simple load and couples to it better) from a single amp/channel.  And single driver speakers must image perfectly in all three dimensions as they present a point source.

The Horn Shoppe and Omega Speakers (here at the circle) are just two vendors of very affordable single driver speakers.  Both offer musical, fast, coherent sound with great imaging and are quite efficient (91 - 96 dB/w/m).  Depending on your room, amp, and tastes a powered sub might be needed, but you'd still have an active system and the crossover would be very low (well out of the sensitive midrange).

Single driver speakers do have their problems (distortion as smaller drivers try to produce deep bass or beaming from larger drivers at high treble), but lets lay to rest the need to produce below 30 Hz or above 15,000 Hz.  Unamplified (real) music just doesn't exist there.  Oh some will fret about needing to reproduce upper harmonics, but another 1/2 octave on either end isn't going to help much.  Marketers have worked on us for 40 years regarding the need for 20 - 20,000 Hz reproduction and audio reviewers brag about how they can hear like bats, but it's just a myth!  Single driver speakers excell at reproducing the essense of music, the mid-range.  If your speaker has problems anywhere near those frequencies, your speaker has fundamental problems, period.

Now I'll be the first to admit single driver speakers typically can't reach 30 Hz while still extending out to 20,000 Hz.  But while the world looks for $1,500 two-way standmounts that might reach down to 50 Hz and still need correction hardware/software, Fostex offers the 8 inch diameter F200A driver that is rated 30-20,000 Hz with 90 dB/w/m at 8 ohms and is rated to handle 80 watt peaks.  A few European companies offer similar products, but not for "only" $375 each.  

A couple of floorstanding designs are/will be available that use the F200A in the $1500 - 2000 per pair range.  One is designed with a bass reflex enclosure, the other uses mass loaded transmission line loading (that extends the bass, evens out the bass impedance hump, and provides a "clearer" midrange.)  The mass loaded transmission line looks like a tapered tube that has some polyfill (mass) stuffing with the driver near the larger/closed end and an open smaller end.

Now I know that's a lot of money for a single driver, but consider what you're not having to get (crossovers, additional drivers, bi-wiring, correction hardware/software) and what you're gaining (ideal imaging and active speaker advantages).  If you add up what that's worth and consider that these drivers are very high quality both in terms of fidelity and construction, especially in the critical mid-range, the choice seems obvious (at least to me).  Besides the single driver concept plays deeply into the "simplier is better" and KISS philosophies.

Rant mode off.

[Rob Babcock]

Besides the range of instuments that really can go well under 30 hz, what a lot of people don't understand is that there's room presence at low freqs.  No, I don't just mean trucks rumbling by in the background, either.

No knock if you like single driver speakers, but many of us aren't limited to only certain kinds of acoustic music that occupies that freq range.  A lot of classical music required good weight & extension, as pianos and organs can both go pretty low.  Can you add a sub and still preserve the phase & coherency virtues of the single driver?  (No sarcasm meant- I'm really curious about that one...).

As for the need for high freq extension; I'm 35, and I know for a fact I can't hear as high of tones as I could at 20.  But I think it's been established to my satifaction that tones above what I can hear can modulate the sounds in the range that I can hear.  That's a can of worms I hate to open- I'm sure BC of VMPS has his reasons for engineering (at great expense) such extended upper freq response.

There's a lot of ways to skin a cat, audio-wise.  I'm pretty intrigued about speaker & room correction.  As our understanding of acoustics & the mechanisms and psychology of hearing improves, and as computer power advances, I think we'll see some remarkable advanced in sound quality.  

But hey, I'm a digital guy.  

[grub]

As DeanShean likes to mention,
what about electronic music?  It could have 20-20K sweeps at any given moment, it's just a matter of pointing and clicking.  Let's just say that a single-driver setup isn't ideal for all types of music.

Perhaps jazz combos and small chamber ensembles would fair nicely, but if you're dealing with a full orchestra, or piano and organ music, there's information below 30hz no doubt, and it's a big part of the presentation.
-->grub

[mb]

I had the very same reaction to the TacT RCS 2.0 in had in my system.  I was immediately thrilled with the new found balance and clarity, especially in the mid to upper bass region.  Over time however, it began to sound artificial and only sounded at its best in one narrow listening position.  Every position in the room needed a separate correction filter to sound right.  I have since removed the RCS and am exploring the world of bass traps and acoustic treatments.  I hope to even the sound throughout the r ...

I've had a rather different experience with DEQ using a Behringer DEQ2496. If anything, the deq makes my system more listenable in just about every position in the room (not just the reference sitting position). I've also added more room treatment to my listening room after putting in deq, and find that they address different aspects of the balance in the room. I would not be surprised that over time, you might end up with a hyrid like what I use.

[JLM]

Rob:

You may have not gathered in everything I said.

Take a single driver speaker, like a $1500/pair driven by Fostex F200As that can reach down to the high 20 Hz range.  Would you really bother adding a sub?  especially for a music only system?  Piano bottoms out at 32 Hz.  How much music is left below 28 Hz that you can hear?

I've had 3-way systems that were capable of 114 dB at 17 Hz so I think that I know what "room presence" is and I can tell you that it's almost always more bother than worth.  Unless you have a very good, hopefully big, room that's dedicated to sound playback you'll excite everything in the room at various higher harmonics and get bloated bass for your troubles.

I'm 47, so my high frequency hearing is surely worse than your's.  I'll accept some value in reproducing up to 20,000 Hz or even somewhat beyond.  But going from 20,000 to 25,000 Hz isn't even a 1/4 octave increase.  Going to 30,000 Hz is still less than 1/2 an octave more.  So I doubt that extension means much.  Now I do agree that wide dispersion below 15,000 Hz is important and that a 8 inch driver like the F200A isn't going to have it even when it's rated out to 20,000 Hz.

But like you said audio if full of compromises.  Personally I'll give up wide despersion at high frequencies to gain all the advantages of a single driver like the F200A.  

BTW 6moons just issued a very positive sneak preview at a speaker that uses a modified Lowther ("full range driver") just for midrange and adds tweeter and dual woofers for a measely $15,000.  Maybe that would satisfy both of us.  

(And I've been a pure digital/solid state guy for 20 years.)

[Rob Babcock]

The "measly $15k" part wouldn't please me!     A bit out of my range.

I really dig the low end, and I can also easily hit the 115 dB mark at 16 hz- to me, it's not "more trouble than it's worth," but YMMV.  Sure, it does take some care to set it up and avoid bass problems, but everything worthwhile takes some work.  We all look for different things in our systems, I guess.

And hey, don't forget about the pipe organ!

I do think that a lot of the improvements from here on forward will come from computers.

[JLM]

Rob:

Extremely deep pipe organ is the one "real" music element that the F200A solution gives up.  But at the end of the day after most have gotten worn out from playing with audio bells and whistles, the middle ground (say 80 - 8,000 Hz which is an old classic range designers aimed for) rules.

I'll be in the market for a new amp/player next year after we move into the new house (with dedicated listening room) and would love to have a fully digital set up with audio PC and digital amps with no analog conversion.  But I'm not keeping up with computer technology, so it'd have to come "user friendly".

[Rob Babcock]

The "ragged, bleeding edge" isn't a place everyone wants to hang out.  And admittedly, pipe organ is an "acid test."  But for those of us who like other forms of music, the low end is something we run up against once and awhile.

But certainly you're not saying the sublime sounds of, say, Bach are mere "bells & whistles?"  Pipe organ might not comprise all you listening, but as the old saying goes, "Be prepared, son.  That's my motto."  

[Val]

Check the Australian company DEQX. Even if their DSP technology can be applied to both speaker and room correction, they suggest room correction should be limited to frequencies below about 200Hz.

Val

[Rob Babcock]

Lemme guess...they make EQ's designed for freqs under 200?     Well, I'll check the link just the same.

[Val]

Rob, I forgot to mention there is a partnership between DEQX and the speaker company NHT. They are bringing radically new speakers to market, corrected for amplitude and phase. Check this thread for things like this:

"... the driver actually puts out a response so flat and accurate that it rivals most power amplifiers. Instead of being in the +/-3dB range or even half of that as some NHTs are, we can get into the +/-.1 or .2dB range. So accurate, in fact, that most magazines are going to have a problem effectively measuring the speaker, though it will most likely improve their measurement technique."

And this NHT press release on the new speakers that are coming out in June or July.

Val