Anyone use speaker impedance correction gadget thingie-magigs?

[The Black Adder]

Hi all.

Does anyone know of these? Anyone find them useful?

I take it that they are just a cap and resistor in series and connected to the speaker before the crossover.

Anyone?...

[The Black Adder]

errr... question answered then I take it... lol

[awkwardbydesign]

A cap and resistor in series across the speaker terminals would be a Zobel network. I have made them to compensate for high capacitance speaker cables, but they sucked the life out of the sound. YMMV. I changed the cables!

[Reffc]

Hi all.

Does anyone know of these? Anyone find them useful?

I take it that they are just a cap and resistor in series and connected to the speaker before the crossover.

Anyone?...

As Awkward says, it's a Zobel. It's usually only necessary where there's a very steep impedance rise on the woofer due to voicecoil inductance, and where the corresponding acoustic output is too steep/non linear to otherwise effect a sensible crossover summation. There are other ways of tackling the problem, as over judicious use of zobels can kill dynamics. Some guides suggest that all filters should use impedance flattening but that's a gross oversimplification of the issues usually just to allow "cookbook" crossover values to be more easily calculated for DIY purposes. This all presupposes that one knows the acoustic response of the raw driver (ie no filter) in the cab in order to make an evaluation of what's needed. As regards adding them to existing crossovers as a "tweak", that's without foundation or purpose unless the conditions outlined earlier have been satisfied and the original designer would likely have accounted for the acoustic performance in a majority of cases, so best leave well alone. In general terms, where drive units need correction or external filters to modify natural driver response, the design should be kept as simple as it needs to be.

[The Black Adder]

Thanks chaps...

I was just curious to know so that clears things up quite a bit.

Ta very much :)

[awkwardbydesign]

If you install one without knowing what you are doing, it will be pure luck if it sounds better. And bad luck if it sounds worse!

[Ammonite Audio]

I've been using MIT speaker cables incorporating this sort of impedance termination for some years; and yes, they do work. The overall improvement does depend on the system, of course, but if I understand these things correctly, it's established electronic design practice and not Foo, even though many experts on forums are happy to denigrate it as such. You don't have to spend thousands, though.

A few years ago Martin Colloms reviewed the Russ Andrews Zapperator, which represents the simplest form of this sort of thing and which regularly attracts great scorn from forum experts. Initially, he wrote them off as being ineffective, but re-visited them after realising that he's been using them with Transparent speaker cables, which already incorporate the same sort of impedance termination networks as MIT etc. So, he did a new review, and then found them to have a profound effect on 'ordinary' cables, even elevating 'bell wire' to a 'really quite good' standard.

So, IMO worth a look. I have no idea what's inside these things, though.

[struth]

Im using mit cables as well...i like them!

[Reffc]

I've been using MIT speaker cables incorporating this sort of impedance termination for some years; and yes, they do work. The overall improvement does depend on the system, of course, but if I understand these things correctly, it's established electronic design practice and not Foo, even though many experts on forums are happy to denigrate it as such. You don't have to spend thousands, though.

A few years ago Martin Colloms reviewed the Russ Andrews Zapperator, which represents the simplest form of this sort of thing and which regularly attracts great scorn from forum experts. Initially, he wrote them off as being ineffective, but re-visited them after realising that he's been using them with Transparent speaker cables, which already incorporate the same sort of impedance termination networks as MIT etc. So, he did a new review, and then found them to have a profound effect on 'ordinary' cables, even elevating 'bell wire' to a 'really quite good' standard.

So, IMO worth a look. I have no idea what's inside these things, though.

That's sort of true Hugo as Zobel networks as applied to speaker cables used to be recommended for impedance matching (typically 8 to 10 Ohms and 100nF at the speaker end of the cable) but as most loudspeaker loads vary with frequency, as does the characteristic impedance of the speaker cable, the use of zobels is questionable in terms of effectiveness/usefulness. The other way of looking at it, as applied to cables, is that in many cases, it doesn't harm. That's really by the bye though because the OP was more referring to speaker filter Zobels, which are applied after the filter, and so that the filter itself "sees" a flat impedance with increased frequency. As has already been alluded to, the use of such zobels can do more harm than good (eg by modifying acoustic output with frequency) unless the acoustic characteristics of the driver unit are known to be problematical, and specifically, without a zobel, making it difficult to engineer a sensible summed response.

[maxrob200]

Some of the Magic boxes have adjustable settings on them as well to allow fine tuning. I think the mega-buck MIT cables have them. Also, does anyone know what the 72V dielectric battery thingy does in Audioquest cables. Their top speaker and interconnect cables have this battery powered device that is supposed to maintain a constant voltage to the dielectric insulation and improving sound quality as a result. Can it be a DIY thing?

[The Black Adder]

Reading in to this and still from a outside perspective 'some say' that it's purely down to the type of components used inside these things. That is the most effective way of getting it 'right' is to find the best type of cap and resistor for the job??? - I can understand that to a degree.

It's a mildly interesting topic. And could these things work better on longer runs of cable opposed to shorter runs?

Paul, I was referring to these thingies being added at the end of the speaker cables (at the input end of the XO).

I once had a zobel implemented at the output to the driver in a version of my early crossovers. I did some experimentation with that and lived with it connected for a couple of weeks, then disconnected. My findings at that point (although not fully) was that the zobel didn't do jack. But at that point in time I was quite new to the Tannoy's.

Not sure if Tannoy's are ripe for this kind of gizmo. I've found some people that use them to great effect but not the RA ones. ...Zapporators!!?... please. :rolleyes: (I wouldn't buy those on principle of the name alone.)

[Firebottle]

Yes but first you have to catch a snake.....


...........then boil it for 72 hours, then refine the oil :)

[awkwardbydesign]

Some of the Magic boxes have adjustable settings on them as well to allow fine tuning. I think the mega-buck MIT cables have them. Also, does anyone know what the 72V dielectric battery thingy does in Audioquest cables. Their top speaker and interconnect cables have this battery powered device that is supposed to maintain a constant voltage to the dielectric insulation and improving sound quality as a result. Can it be a DIY thing?

As I understand it, some people thought that studio cables with microphone phantom power supplies sounded better with the power turned on. These are generally 48v. It was suspected that "charging" the cable dielectric was the reason for the improvement, so there has been experimentation with hifi cables. I have some suitable cables, so I may try it myself one day. Until then I won't have an opinion on the matter, but I won't be spending lots of money on them! The batteries should last almost forever, as the current draw is so low, and the exact voltage can be set using several batteries in series. One experimenter found 36v sounded best, to him.

[Reffc]

Sorry for the confusion Joe...I had read the (OP wording in bold) which directly suggested "speaker impedance correction". A zobel before the filter will not correct specific drive unit rising impedance and is of arguably little merit in the scheme of things.

[TheMooN]

Perhaps consider the Zero's by Paul Speltz http://www.zeroimpedance.com

[The Black Adder]

Thanks Paul, that's fair enough.

[The Black Adder]

Perhaps consider the Zero's by Paul Speltz http://www.zeroimpedance.com

Thanks.

Hmm... Dunno, I'd rather get the low down on how these things work (or if they work at all) to be honest and make some myself as it's not that fiddly.

[TheMooN]

Well, If you are able to wind them to tolerance , and for less than £350 delivered, Then Go with God!

https://www.divineaudio.co.uk/anti-cables-naked-zero-autoformers



Thanks.

Hmm... Dunno, I'd rather get the low down on how these things work (or if they work at all) to be honest and make some myself as it's not that fiddly.

[The Black Adder]

God?... who is dat den then... lol

I've looked at the website. I've personally never heard of those before.

[cloth-ears]

Zobel networks are often used in quality crossovers. Adding one to a good speaker with a balanced crossover is pretty much a waste IMHO. If on the other hand you are driving a so called single “full range” speaker then a Zobel will help to iron out the impedance rise that moving coil speaker’s exhibit with a rise in frequency. Without one, mid range and high frequencies may sound a tad splashy or even squawk on female vocals.