Powered speakers show audiophiles are confused

@donavabdear ,

For you Genelec, the mid is the waveguide for the tweeter and the front is the waveguide for the mid, so we better hope things have gotten better.

Reflections, higher order modes, throat and mouth and edge diffraction, resonances, it is not as easy as it seems.

The answer is the problem still exists, but we have gotten much better at making them, not the least because we have software now (even in the DIY community) that really helps to automate and optimize aspects of the designs so instead of making a 100 revisions or more CNCing plastic, you are now making 5-10 and printing them. How many you need usually comes down to how good your model is of the underlying driver.

Our software like our competitors is a mix of proprietary software and off the shelf generic tools and plug-ins. Obviously can't post that, but I can post stuff out in the "community" that is really good. This reminded me of a interview with Earl Geddes, always as crotchety as ever, but also always interesting. I like the guy, don't get me wrong, but he is like that friend you have that is always cranky :-)

The video is rather apropos, as he mentions active and passive speakers too, though I consider some of this comments outdated. Some however, are not. The most important one is that active speaker design does not magically solve all issues. You need to start first by being a good "passive" or in essence fundamental speaker designer.

https://www.youtube.com/watch?v=nhe8VfuTg08

More relevant to the discussion is his mention of what he considers, and many agree, of the importance of constant directivity to ensure a speaker sounds good in most environments. This is a implementation embodiment of the Toole\Harman research showing smooth off-axis response is important. That does not solve the waveguide issue, it just give credence to why it is important to solve it. Very relevant to the discussion is the use of software for wave guide design. Geddes says that even the DIY S/W, or at least semi open source, does a better job than he was able to do. The software and a comprehensive discussion happened here:

https://www.diyaudio.com/community/threads/acoustic-horn-design-the-easy-way-ath4.338806/

@thespeakerdude Great, thank you for that. What is a problem is longer wave guides or horns or anything that is trying to direct the wave. Call 1k a 1 foot long wave (close enough) 2k is 6 inches 4k is 3, at this point horns and curved boxes with computer curves easily confuse the wave by bouncing them in and around whatever kind of guide the designer has made, there is no way out of that sinareo. Horns are never ok, they may sound good but the huge difference in size of waves doesn’t allow a horn to accommodate multiple frequencies properly. A traditional cone driver is simply a piston that creates the wave but doesn’t redirect it, (except for the edges and things like that) as horns do. My Genelecs use the term wave guide but it’s really wave takeoff more than anything because the size of the waves and the depth of the high frequency and mid frequency voice coil throw is so much shorter, they aren’t designed to guide the frequencies like the Tannoy and the Uri’s of the past which sounded like everything was pumped through a bullhorn, even a multi million dollar showcases theater with an 80 inch sub has got this wrong IMO. The 80 inch driver is a perfect example, what would that horn have to look like well it’s impossible to make a horn that accommodates frequencies that large between 1 and 20Hz you would need 20 huge horns. In that video they described midrange center channels that used a curve to redirect the waves to the audience, this is a big compromise in a no compromise room. A great Director of photography I worked in the movies always spoke of the light he used as "them" he would always bounce, diffuse, cut and all the other things DPs do with light by thinking of light as little particles that bounces around, so I told him use one of my sound diffusers to bounce his light it only makes sense, he was amazed he hadn’t ever seen that before. The moral of the story is if you think of the sound as particles that interact with each other you would never expect to send them down a horn and expect to not have them interact. Hope that’s a tiny bit clear.

speaker dude wrote, "I won't speak for @donavabdear, but I will speak for myself that the question is essentially irrelevant and is begging an answer. Phase corrected is essential for any working speaker design, time corrected looks much better on a marketing sheet than providing verifiable listener benefits. And yes, I have personally done the testing. Dynamic correctness, dynamic excitement seem to be implying the same thing. How long can you play, and what effects of any concerning dynamic compression. Horn loading / compression drivers is not the only way to achieve this of course. Horns provide, properly designed, constant directivity, but using a standard woofer/mif-woofer and a wave guide tweeter provides similar benefits without the side effects of vertical directivity lobing which can cause unpleasant reflections off vertical surfaces, likely one of the reasons why some people "don't like horns".  I think we can agree that a real horn loaded speaker at 20Hz, even a tapped horn is rather enormous and outside the realistic realm for most people. To achieve true directivity at the frequency is just unrealistic and you are not going to avoid room modes. Velocity/position feedback eliminates power compression issues in subs, and cheap efficient amplification is plentiful. Just put in a bunch of power subs and be done with it."

I respectfully beg to differ.  My DIY speaker system uses Bill Fitzmaurice designed HT Tuba 25 Hz quarter wave folded corner horns.  The output at 25 HZ in my DEQX equalized system is identical to the output at the 1 kHz reference tone.  The output at 20 HZ is still audible and musically useful.  They are 18 cubic feet each but wearing a nice coat of Blonde Burmese teak veneer with solid teak and brass trim and tucked away in the corners where they need to be they don't seem particularly obtrusive to me. 

Including the horn path in the bass bin plus the distance out to the midrange horn which is well out into the room where it can image better makes the separation between the acoustic centers and the woofer and the AER BD3 midrange drivers over 16 feet.  The time correction provided by the DEQX DSP makes the acoustic centers of those drivers sound as though they are within 3 mm (less than 1/8 inch) of each other.  That is not in any way irrelevant.  If you have ever heard properly executed horn deep bass I think you would understand the difference between that and using a bunch of power subs and perhaps even learn what I mean by dynamic excitement.  I notice that Genelecs best subwoofer is already 6 dB down at 27 HZ.

My system is active using six channels of amplification. Contrary to donavabdears contention that audiophiles who don't use a bunch of little active cones and domes in a box are confused I respectfully beg to differ with him also.

@kingharold

They are 18 cubic feet each but wearing a nice coat of Blonde Burmese teak veneer with solid teak and brass trim and tucked away in the corners where they need to be they don’t seem particularly obtrusive to me.

Thanks for posting this, the pics you posted are stunning. Some of the wannabes in this thread are keyboard warriors who are simply posers. Your handle is certainly appropriate from what I see in your system profile, nice job.

I would like to know more about the deep horn loaded bass you describe. What type of space do you need, budget, etc. Thanks.

@thespeakerdude wrote:

Have you been following what I said I do? Speakers for professional applications? Do you think that just means studio speakers? @donavabdear mixes for movies where you are trying to "recreate" real dynamic events.

And your point is? @donavabdear made no effort to limit his views on dynamics to a given application of reproduction, but rather made a broad statement. I replied accordingly. To most here it’s about home audio reproduction. Dynamics should apply as one sees fit, however setting the bar high here isn’t some fad but rather acting on a hugely important aspect of music (and movie) reproduction. That it isn’t a higher priority has more to do with spousal demands and interior decoration (and even vanity) than a conscious "no thanks."

20CuFt is not really enough for a proper horn loading at 20Hz.

You wrote ".. a real horn loaded speaker at 20Hz," and I’m telling you a 20cf. quarter wave tapped horn with a tune a ~22Hz will do honest and proper 20Hz - period. What isn’t proper is asking a smaller size, lower eff. direct radiator doing the same, even with a surplus of power. And horn sub iterations can be in multiples as well.

Tell me @phusis, what is your personal definition of "dynamics"?

Let me put it this way: my take on dynamics is they matter more than many if not most audiophiles care to pursue via their home setup. Which brings me to your next question..

What is a sufficient peak db level?

To me "sufficient" peak dB level is a max. required SPL number with some +20dB’s of added headroom. A pair of corner placed (i.e.: with boundary gain) high eff. tapped horn subs and high eff. pro cinema main speakers with a combined 2.3kW actively per channel can shell out +125dB’s at the LP (~11ft. listening distance), full-range, so backwards math gives an easy 105dB’s with +20dB’s of headroom - within my actual required range.

Please note that I don’t blast my ears with +110dB peaks like a daily meal, if rarely at all. However, an abundance of full-range headroom provides wholly effortless, low distortion playback that few get to experience, even at levels that are downright physical in nature. The clean (and full-range) dynamic bandwidth not least comes in handy with Blu-ray/4K UHD playback of movies.

I could go on about describing this, but it really requires of one to experience it first-hand to know it. Suffice to say that when you have a bunch of high eff., large diameter transducers (or force multiplied via acoustic transformation) that move very little, yet while producing tremendous SPL’s at the LP, it can provide a very relaxed, full and immersive feel of sound that’s simply not attainable from smaller, low eff. speaker packages.

Coming down to it it’s really about the benchmark I’ve set out to go by within a range of core parameters, and has come to achieve in some measure. ’Core parameters’ may not apply similarly to all, and a MFR rarely has the luxury to go all-out in regards to core physics of reproduction, for reasons already outlined by you. Fortunately DIY and an open approach to which segment of gear is used can change that, relatively uninhibited.

What is a peak db level listening to an orchestra say 10 rows from the stage?

10th row with a large symphony orchestra during tutties? I’d say 105-110dB’s.

How often are you trying to recreate a Saturn V launch?

I don’t, really, and you obviously missed my point. Another example, here from the world of cars, and to hopefully get through with my point this time around: if, say, a Formula car is your effective out-of-reach reference, then for sure a Porsche 911 Carrera GTS is still faster than a Citroen Berlingo, and who among fast-car aficionados wouldn’t appreciate that difference in performance - even without achieving the speed of an F1 racer? Moreover, you’d certainly get a closer feel of what it means driving F1.