D-Fend

Re: D-Fend

I already wrote about this when this was posted over on PSW(? maybe here too).

Simply stated it is a HF solid state chopper (kind of like a sophisticated light dimmer), so after filtering the amp output looks like less voltage to the speaker, and the speaker looks like a higher impedance load to the amp, so both ends are happy (even the tree huggers are happy because no watts were wasted other than the modest drive electronics draw).

One very tiny ding is that it parasitically steals power from the amp output signal, but if properly done this should not cause audible distortion.
The pro is that this allows you to idiot proof (customer proof) passive speakers which is surely attractive for premium speaker makers. The con is it will add cost that may keep it from being used in the lower priced gear, that probably needs it the most. Near universal use, could drive some economy of scale, but these are redundant for powered speakers and well managed systems with easy access to amp gain, so I am not that optimistic about these becoming ubiquitous everywhere. It is patented so somebody is probably hoping for that, and I wish them luck.

I give it one thumb up (for cleverness), but my boring by now advocacy of smart powered speakers makes this superfluous. I see a niche with premium passive speaker sellers, and if the price is right this could find a home lower down the food chain where the volume is, but I know how viciously sharp pencil the value segments are.

JR
 
Re: D-Fend

This is the detailed video. They should have a summary video too, with a demo about thirty seconds or one minute into it.

Very wooden delivery. No regard at all for today's CG and attention-deficit Blackberry-driven generation. Otherwise fine by me though. This guy is obviously a problem solver.

I noticed the usage of "in the past" to describe any other form of protection, and "now" to describe their own.
 
Re: D-Fend

Jeff Babcock said:
Hi JR,
Sorry, I don't pay much attention to PSW other than very occasionally anymore. Thanks for your insight from a manufacturer perspective.
Click to expand...

No worries in fact the reminder was good... IIRC Ivan was supposed to be getting one to check out (with all his spare time :), and was was going to give us report.

As with any dynamic protection device, the perceived performance may be influenced by things that have nothing to do with the technology's baseline performance (like side chain time constants). A lot of tweaking goes on inside amp clip limiters to make them sound relatively neutral, while this may have a little more flexibility to operate more gracefully, except for excursion protection that needs to be quick.

JR
 
Re: D-Fend

They were showing the D-fend at InfoComm and it sounded like they were looking at flexibility in the the components, etc. to allow supporting a range of price points and products. They also discussed developing an external, standalone version for use in existing systems or with products without it integrated. I'm definitely interested to hear Ivan's comments after he's had a chance to check it out.
 
Re: D-Fend

Not to be too repetitious, IMO this really makes the most sense for passive protection on a per driver basis. If one were to make this an external full range black box there are all kinds of other considerations.

We'll see. The market will sort this out.

JR
 
Re: D-Fend

John Roberts said:
Not to be too repetitious, IMO this really makes the most sense for passive protection on a per driver basis. If one were to make this an external full range black box there are all kinds of other considerations.

We'll see. The market will sort this out.

JR
Click to expand...

I would agree that a driver specific application would be best. But there is the ecomonics to be considered. On smaller boxes a single unit may be best, but on more expensive boxes, the additional protection could be good.

It also depends on the specific loudspeaker. If one band is the "weak point", then it oculd possibly be tailored for greater protection on that particular band.

The last I heard they are working on an easier interface for programming. When that is developed, we will get some untis to play with.
 
Re: D-Fend

I will ASSume they have nailed the mechanics of how to reduce the power, but there is a lot of room for the exactly when with attack/release/even nonlinear threshold responses to just protect the drivers from failure or avoid power compression...etc.

They would be wise to give speaker manufacturers as much flexibility as they ask for and listen to them carefully because people have been dealing with doing this for decades, albeit higher upstream (of course Eminence has probably been party to this discussion all along).

This technology has the potential to really kick ass, if they sense or detect thermal status of the driver, but the cost of doing this as a separate function, vs integrating into a "system" remains the open question.

In my crystal ball future full of powered speakers this can probably be done cheaper elsewhere. Of course there is another vision of the future with one of these mounted to every driver...

not my vision unfortunately, but the future hasn't happened yet, so I can't know.

JR
 
Re: D-Fend

John Roberts said:
In my crystal ball future full of powered speakers this can probably be done cheaper elsewhere. Of course there is another vision of the future with one of these mounted to every driver...

not my vision unfortunately, but the future hasn't happened yet, so I can't know.

JR
Click to expand...
ANd here is where your crystal ball shatters. Let's assume you are correct (I have no reason to believe you are not correct) and loudspeakers are pretty much
blowout proof.

That is a good thing-or is it? At least now-there is a little bit of responsibility on the part of the user. But if you can just keep on "dumping the power" to the loudspeaker, the dynamic range will get even more squashed than it is now. Amps will be run into higher levels of clipping and what we call music will take on a whole different aspect-at least in the bottom parts of the market.

At least now it comes out of peoples pockets when they screw up.

Yes it could be good for the manufacturers to not have to deal with as many returns and such, but what it "sounds like", may have a lot to be desired.

Maybe we will be gone by then and it won't bother us.

But if you think about it, the quality of music is going downhill as technology gets better. We used to only have live unamplified music. Can't get much better than that. Then we got records and some of the life was sucked out. Then came FM-more life getting sucked out, them MP3's even more live getting sucked out. and now if you drive a loudspeaker with a completely squashed signal and it not tear up-even more life getting sucked out.

So maybe music styles will adapt, any maybe it is just me-but I still like dynamics in the sound.
 
Re: D-Fend

My friend,, you are over thinking this,,, it is the natural progression of technology to reduce or eliminate nuisance failures.

Pro sound is a small segment of the larger audio market that won't need such circuitry, or will invisibly include PTC fuses or whatever is cheaper.

My crystal ball doesn't include consoles and sound men, but i'll never live long enough to know if i was right.

JR
 
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