Do active speakers interest you? Also, let's talk directivity


Hey all. Don't think I've ever made a thread here. This is a super interesting community for me. I'm an audio professional, a mastering engineer and music educator. I'm someone who differs from much of the pro community, in that I don't see a difference between "pro" systems and "high-end" systems. 

There is one way they often differ, and that is in terms of directivity. Home systems are more frequently omni, while and studio or live sound requires directivity.

This was definitely the case in the 70s, back when audiophiles still had parties :D 

It's very hard to set up a directional system to fill a large room evenly unless you use a line array.

But let's be honest. Aren't we mostly sitting and listening, and hoping for a good image? We aren't expecting every spot in a big room to sound exactly the same for every guest. Personally, my social life is 95% virtual now and I am generally listening in my mastering room. I have a high end system in every room in my house, but my wife uses the living room system more than me (and she has better taste in music, so it's nice to learn about some new artists when she decides to put something on from he collection).

Anyway, I'm designing an active system. Though the cabinet is not large, with a combination of Hoge's principles and active electronics, we will achieve accurate response through to 20hz.

The reason to choose an active crossover is very obvious. Sending power directly to each driver allows us to use a very low sensitivity woofer, which thus plays much deeper than expected. We are using a ported woofer and a sealed midrange/hi cabinet, which are not sold separately. An interesting feature is the the very low-crossed ribbon tweeter carrying all of the high midrange and treble

It's an 1800w system, aimed at both the professional and home market. I'm curious, does this sound interesting to anyone? We are intending to have a prototype ready by 2022, so it is a ways off.

Part of the directivity concept is also dealing with room issues. Cancelling the rear energy of the woofers can help. I am inspired by Bruno and Merjin (whatever  his name :P). a big part of our concept has to do with advanced acoustic materials, which I don't want to discuss too much, as I don't think anyone else has thought of it or connected with that maker, yet

Curious to hear people's thoughts!
128x128mehtayoungs
@OccasionallyCurrent - Thanks so much, I deeply appreciate that. One thing that I am known for, locally and in my global network, is finding steals for people. It doesn't matter to me if it's from my inventory, I just want people to have the best audio they can afford. To me, a soundsystem is an important health product, not a luxury item. It's normal for houses to be outfitted with expensive appliances that facilitate daily living. 

I'm not the type to listen to music all day. Listening to music has been about 50% of my work for a long time, and while I tend to love everything that gets submitted, ears to get fatigued. Similarly, I only cook once or twice per day. Regardless, if I had a substandard stove and oven, my life would be abysmal.

Although at this stage in the design, we are not cutting any corners (but rather, rounding them haha), we intend for this product to be accessible. We are just a group of audio nerds, based in the middle of nowhere. Someone mentioned aerogel - right on the money, although like they said, aerogel is too expensive for a commercial design.

We are looking at a new  material which is gaining traction as a sound insulator. No one else is using it in audio. It has the same special quality as aerogel. It comes in bricks that must be hewn, so we won't be constructing the cabinets themselves from the material. Just the baffle, and for the rear cancellation. 

DSP is a big thing these days. I have a couple hesitations.

1) Timing.

This is the big, BIG one. Linear phase equalization ALWAYS causes a delay for ANY DSP that I know of. Linear phase is important, it sounds much better in the high frequencies. If a subwoofer is crossed low enough, it doesn't require linear phase, the phase issues are not audible. Anything above 150hz and you could run into trouble. This has been my own observation and Linkwitz has confirmed it on his personal site. He's a very scientific guy, lots of respect for him. He's also open to anyone repeating his experiments and sharing their observations, he's not a stick in the mud.

For professional speakers, there cannot be any delay from input to output. I know that some of these very advanced developers have code and systems that have no noticeable delay. It's more my experiences performing on early DSP-processed systems telling me to wait until the technology is perfect in the same way that analog is now.


2) Proprietary code. 

I have a DSP code researcher on the team, and I believe that within 5 years, we will be doing work in the DSP area. There is no doubt in my mind that it is the future, and as a mastering engineer, although I learned from someone who used only analog hardware to DAT tape, virtual DSP processors are now good enough, sonically speaking. Latency is the issue, and no one who has solved it is willing to share that knowledge (trust me, I've asked the bigwigs directly, and the answer was a resounding NO)

I'm glad I waited until I had something important to share, instead of becoming known as the guy who beaked all the SET enthusiasts who think that putting more than 1 watt into a driver is heresy (just a little tease - my first job at 14 years was as a comedy writer, and once habits form, y'know)



This is one of the most interesting discussion threads I have read on this site.  It has been most informative reading the back and forth answers.  Plus, you smoked kenjit and he hasn't chimed back in -- which I consider a victory for you.  Please keep us updated.  Some of the discussion has been over my head at this point.  I need to re-read and do some private research to catch up.  Thanks!
Go for it. 

Four years ago I demoed (is that a real word?) a pair of Kii's at home.  I was using then horns from Avant Garde  - Duo Beta's. 

Though the duo's used active bass units, it was easy to see what I was missing. Both in terms of deep bass and intelligibility.  Out with the horns, in with the Kii's.

Having said that, and with all the hype about directivity and shaped soundfields (in fairness, the shaping actually does work for bass) and perfect phase, I never bothered with room treatment, thinking it unnecessary.

A few weeks ago a friend insisted I roll up a small carpet and place it at any first reflection point. The effect was immediately obvious.  Now all 10 early reflection points in my room have been treated.  I never imagined this effect... Like focussing a camera.

So to the point which may sound a little crazy: when you finally present your speakers to the world it would be honest (not a good word? No offence meant) to offer 10 X 2 foot square foam abfusers (the new tech ones work in a way I would not have believed before trying) and a little mirror as an optional accessory.  Cost under 100 bucks.  Before making claims that room effects are 'minimised'.

Best wishes

PS Bruno is one of my heroes too.


@inorganic Yes, the famous ATC midrange. >300-3k. They used to sell them, but the mid driver is their bag. Guzauki-Swist is using that driver in a $30k system. Not sure if anyone else is able to get them from ATC at all now.

I have a very different approach to midrange. Midbass and low mid coherence is very important. I'm a baritone vocalist and bass guitarist, so I don't like it when the "power zone" is disembodied from the low midrange.

Most musical fundamentals are found between 150 and 600hz. This is what people people call "warmth" in music (trust that I'm willing to die on this hill, warmth = low midrange). That is the range of the fundamental tones of our voices. 

330hz, the typical crossover point for the famous ATC 3" dome mid, this right in the heart of what we consider to be musical frequency. It is the critical midrange.

My design uses a 5.25" midrange crossed nearly 200hz lower. Of course, such a large midrange will beam if it is crossed too high, and like any 5" or larger driver (that I've found) the response starts to lose precision above 1000hz.

For many people, upper midrange, 1k-3k is the critical zone. Certainly, those frequencies are more present - they are what we call "presence" when we are discussing audio. 

Our tweeter is planar, and we cross it much lower than standard, even lower than Dutch & Dutch 8c. It  covers from 1k - 35khz, a phenomenal range for a single driver. What those numbers don't tell you is the phenomenal resolution of both detail and dynamics. 

The system uses two critically dampened cabinets. We will include an adjustable, non-resonant pole, so that the top will sit at the optimum height. In practice, the mid and top would be fairly close together, as the low driver will be about 20 inches off the ground. There will also be the option of using a very hefty stand and fully decoupling the bass driver from the floor.

Modular approaches are not as easy to market. Fortunately, this is not modular. The active electronics are all contained within the bass unit, and although the top *could* be connected to another amp, this is forbidden, as without the active electronics, the drivers would certainly be damaged. Also, who wants to listen to music without low frequencies?

It can be set up in different ways, depending on what is required. With 1800 watts for the whole system, it could serve as a PA system for a small party. The poles will allow for standing-height listening, although that might be wishful thinking at this point.