ACI Maestro... (1 Viewer)

[Craig Chase]

Jack... things learned doing reviews...

1. If you don't do measurements, your review is invalid.
2. If you DO do measurements, they are wrong, and your review is invalid.

 

[Jack Gilvey]

Yup...for anyone but you in your room. Interesting reading for family and friends, perhaps. I've learned that people "prefer" any number of things...for any number of reasons. Even most "measurements" are not under repeatable curcumstances...and are suspect as a result. Does this mean that I rarely lend much credence to "reviews"? Yes.


I think that Keith Yates' recent series in Ultimate A/V should be required reading...very educational for those who don't really understand what "measurements" means.

 

[Craig Chase]

deleted

 

[Edward J M]

Cross it off the list; it doesn't meet Dave's criteria.

Now if you had said the B4+ was lightning fast, with good sock and just a hint of wool.....well, NOW your talkin'; I'd be first in line clutching a fistful of greenbacks.

 

[Mike Dzurko]

You guys are cracking me up Great way to start the day. Enjoy!

 

[Craig Chase]

It IS lightning fast, but with a hint of Cotton... Are you still in the game ?

 

[dave alan]

Craig,

Don't cross the B4+ off the list yet...the thought of a monstrous black box that will play incredibly loud in my 3.500 cu ft room at a frequency I can't hear is definitely intriguing to me, yet, I keep stumbling over that darned amp clipping/dynamic compression thingy keeping me from 'hitting' 121 dB @ 20 Hz. a definite sound quality bummer.

The plate amp that comes with THAT thing must have some impressive power rating, eh? Oh, wait...amplifier optional...need more tests/specs...please list. What about slew rate and damping factor??

(Closing eyes and imagining listening to the sound while outside in my 2 acre back yard that's devoid of trees, etc., as I read the SPL spec posted).

 

[steve nn]

>>>Stay tuned for the latest HTF subwoofer review by yours truly.......hailing all the way from sunny California - where they still turn grapes into raisins the old fashioned way - is none other than the Hsu Research STF-2!!>Jack... things learned doing reviews...

1. If you don't do measurements, your review is invalid.
2. If you DO do measurements, they are wrong, and your review is invalid.

 

[Edward J M]

Yes, Steve - I've got some catching up to do before I do a PC-Ultra review. But let's not hi-jack the thread.

While we've got Mike's ear, maybe he can tell us why he ultimately selected a sealed design, the topology of his amp (pretty beefy looking trans I see), if his current sensing design is similar to that used in the Velo CHT-15, and if the Maestro uses different EQ curves for the speaker level vs. Theater inputs and if so which EQ curves is uses to achieve the rated extension. And is the rated extension (-3 dB at 19 Hz) typical for in-room with room gain included, or is this the quasi anechoic response?

 

[Mike Dzurko]

>>>While we've got Mike's ear, maybe he can tell us why he ultimately selected a sealed design, the topology of his amp (pretty beefy looking trans I see), if his current sensing design is similar to that used in the Velo CHT-15, and if the Maestro uses different EQ curves for the speaker level vs. Theater inputs and if so which EQ curves is uses to achieve the rated extension. And is the rated extension (-3 dB at 19 Hz) typical for in-room with room gain included, or is this the quasi anechoic response? >>>>

Edward:

Early on we did a number of different subwoofer designs including sealed, 4th order, various compound loads, bandpass, and T-lines. For the last ten years or so our designs have been sealed with Q > .6. I like the way they sound . . . and measure Our customers have apparently agreed, as they've been very well accepted and we've gotten tons of great feedback from users.

I don't know anything about the details of the Velos. Our amplifiers are custom built for us here in the U.S. Essentially the same amp is used in the Force, Titan, and Maestro. Each uses a different attitude card that determines the EQ and limiting functions. The Maestro is essentially two bridged amps to reach the needed power. I love these amps. Besides offering the performance we want they are extremely reliable, and the OEM manufacturer really stands behind them. We could get similar power for tiny fraction of the cost, but I'm not convinced about the quality.

All three inputs on the Maestro are line-level. We supply simply pigtail speaker adapters with each sub for those who need them. The Theater input is designed to the original THX spec of 3db down at 35Hz. The other two inputs are designed for 19Hz. All measurements are anechoic. Thanks for asking!

 

[Brian Bunge]

Craig,

Of all your reviews, this one is the one that interests me the most. The first subs I built used the drivers in ACI's Titan and Force subs back when they were still available to the DIY'er. So I'm intimately familiar with the quality of the drivers that ACI uses in their products. I can only assume that the 15" driver in the Maestro follows in their footsteps. Over time I too have grown rather fond of low Q, sealed designs.

Mike, as always thanks for the great products. I know the Maestro will be just as big a hit as the Titan and Force have become.

 

[Edward J M]

Thanks Mike:

Would it be safe to say that the Q = 0.6 only applies to the theater input, where F3 is 35 Hz?

If so (and considering the estimated internal volume of the enclosure) it would seem the theater input uses little or no EQ?

Does the application of EQ (at the speaker inputs) to achieve an F3 of 19 Hz (anechoic) alter the total Q of the system?

If so, is the transient behavior (impulse response) of the Maestro different for the theater input vs. the speaker input?

Can the equalized speaker level inputs be used for HT applications (for greater extension) if the user keeps the overall volume within the clean/safe limits of the Maestro? Or would this be considered a misapplication of the intended use of the product?

Thanks,

Ed

 

[Mike Dzurko]

Brian:
Good to see, er hear from you again. I hope all is well w/you and you family. Thank you for the kind comments. I think it’s safe to say the Maestro is already a bigger hit than the Titan or Force. At least it’s pretty BIG when we’re building and packing them All the best to you and RAD.


Ed:

Actually everything is really designed around what we feel are the “normal” inputs; the left and or right. Whether used at line level (the sub out from a Processor), or with the speaker level adapters, (a two channel system without preamp outputs), these are the inputs that we feel measure and sound the best. The theater input is in some ways a hold over. It is useful in those rare situations where someone wants it REALLY loud and is willing to give up some sound quality. Rap, Industrial type music, etc. comes to mind.

I’d say the vast majority of users use the left or right inputs on all our sub models. That’s the way I use it too.

 

[Robert_Gaither]

Rumor has it that he is ... he has the ability to drink beer from either hand...

 

[Craig Chase]

Robert... Not only drink a beer with each hand, but smoke a cigar while doing so...

This review will be a lot of fun... Our main theater room is 5700^3 feet. It will be interesting to discover how the Maestro handles a room that size.

 

[Edward J M]

Thanks, Mike.

Ironically, I would imagine "purists" might find the Theater input (if it is truly unequalized) more attractive, as it should preserve Q = 0.6 and a true 2nd order alignment, with the lower group delay and optimal transient behavior the low Q sealed subwoofer is known for. Of course the downside would be an F3 of 35 Hz, but strictly for popular music applications, that would seem deep enough. What are your thoughts?

Craig, the B4+ in the 20 Hz tune would probably match up best with the Maestro (using the speaker inputs) in terms of anechoic extension.

 

[Craig Chase]

Ed ... it is in 20 Hz mode now... This is easy enough...

 

[steve nn]

>>>It will be interesting to discover how the Maestro handles a room that size.

 

[Craig Chase]

Steve... It is amazing how the room shrinks when my kids bring friends in to watch a movie....

And yes... It will be fun to see if a single Maestro can deliver all the home theater and music bass desired on a larger room. Tests like Titan AE, LOTR:ROTK and other great bass movies will most definitely be used...

 

[Mike Dzurko]

Ed:

Very assute, and you'd be dead on except the Q> .6 with F3 at 19 sounds even better for a purist than Q > .6, F3 35.