Shame AVI nobbled their Lab series of amps

[plastic penguin]

I thought you won't be interested so I'm not ready to support my claim.. wouldn't change anything I guess? besides, it's just a little evidence cause it's only 1 licker ( you) and not like 10s of Avi lickers..

So I called your bluff.

I've rarely directly mentioned the Leema for three mains reasons:

1) The Puise isn't made anymore, so has no relevance when people are looking for current amps

2) Not heard any other Leema product

3) They are fairly rare on the s/hand market. Generally people like to keep them. That says quite a bit about their sound quality, and connectivity.

I don't object to anyone liking whatever set-up they gravitate to, but they need to keep it whatever threads are active at the time. This thread was nothing more than a production question.

 

[lpv]

this forum was nothing more than 'What's passive' and now is 'What's active as well' which is alright I believe and if one day some group of people start to glorify electrostatics it will be fine with me..

 

[thewinelake.]

People tend to recommend what they themselves have liked. If quite a few people like actives then that's what we'll see. Doesn't necessarily mean they would say passive systems don't have their place.

 

[thewinelake.]

Who is the colonel?

 

[lindsayt]

this forum was nothing more than 'What's passive' and now is 'What's active as well' which is alright I believe and if one day some group of people start to glorify electrostatics it will be fine with me..

When was that?

 

[Andrewjvt]

What's wrong with being an AVI fan boy, anyway ?

JC

Nothing unless the active brigade resort to brainwashing or answering ever post with the suggestion that active is the only way to go. 

Agreed: This is the problem I've found: Their way is only way regardless of what people require... I don't object to active, it's their owners who constantly thrust it down others throats.

I think that is unfair.

I often suggest that, for many people, a system built around a pair of late model ADM9/10 offer outstanding value for money, and I own neither.

If the 2 toslink and single analog inputs are sufficient, not the case for everyone, then I think you would be hard pressed to match that performance from 'traditional' components.

Similarly, if you are looking for a system to play a lot of modern music that requires a very 'solid' bass output, then some of the better studio monitors will comfortably outperform passive systems at comparable prices.

Here's me thinking this forum was called "What Hi-Fi?" and not "What Active?"

I thought hifi meant high fidelity and not high amount of boxes

 

[Ashley James]

Those were measurements made of inductors made by a company that had supplied most of the U.K. Speaker industry for years. The report was written by Martin Grindrod BSc Electronic Eng.

Are you qualified in any way?

 

[lpv]

this forum was nothing more than 'What's passive' and now is 'What's active as well' which is alright I believe and if one day some group of people start to glorify electrostatics it will be fine with me..

When was that?

you tend not to answer my questions but I'll answer yours: about 3 years ago.

 

[Dave_]

this forum was nothing more than 'What's passive' and now is 'What's active as well' which is alright I believe and if one day some group of people start to glorify electrostatics it will be fine with me..

When was that?

you tend not to answer my questions but I'll answer yours: about 3 years ago.

Get over yourself!

Actives were being discussed on here more than 3 years ago and there's been many owners of active systems participating in the forum for as long as I've been a member here...

 

[lpv]

not much when I've join forum about 3 years ago.. I've been looking for a set up for myself and reading the forum looking for advice.. no one mentioned actives back then.. I probably wouldn't buy broken kef's and 45 watts rotel for a £1000 if anyone could tell me: go and have a listen to some actives, like you can hear it now.. you with me?

 

[chebby]

not much when I've join forum about 3 years ago.. I've been looking for a set up for myself and reading the forum looking for advice.. no one mentioned actives back then..

http://www.whathifi.com/forum/hi-fi/active-speakers-club

... it pre-dates your membership by almost a year and was only a tiny fraction of the active speaker discussions that were regularly going on for years before it.

 

[lpv]

I remember the active speakers club thread.. but still presence of active speakers over 3 years ago wasn't as stong as today and if it was I simply missed it.. today someone ask for a advice on a budget ( well, anything up to £1000) and most probably actives are mentioned..

 

[lindsayt]

this forum was nothing more than 'What's passive' and now is 'What's active as well' which is alright I believe and if one day some group of people start to glorify electrostatics it will be fine with me..

When was that?

you tend not to answer my questions but I'll answer yours: about 3 years ago.

It will take me a couple of days to compose and type out my reply to your previous question about the major flaws in AVI drivers and cabinets.

It only took me 30 seconds to compose and type my 3 word question "When was that?"

There's a useful tool on the What Hi-fi forum where you can sort threads by the number of replies. Simply click "Replies" twice on the main page for this section of the forum.

On the first page you'll see at least 3 threads older than 3 years where AVI actives get plugged to high heaven.

 

[lindsayt]

Those were measurements made of inductors made by a company that had supplied most of the U.K. Speaker industry for years. The report was written by Martin Grindrod BSc Electronic Eng.

Are you qualified in any way?

So we still don't know exactly which inductors were measured? It's not as if this information would be a trade secret, is it?

We still don't know why those inductors either weren't measured at lower power levels than 10 watts, or why the measurements weren't published?

Oh, hang on. We do know why. It's because it wouldn't suit your marketing purposes.

And you can lay off the ad hominem. Martin Grindrod could be the President of the IEEE. It still wouldn't stop your previous post (that I responded to) being a complete load of misleading marketing hogwash.

 

[lindsayt]

...And at the end of the day, active or passive is the icing on the cake. It's the drivers and cabinet design that are the sponge and the filling of the cake. In the case of AVI speakers these are seriously flawed.

can you elaborate?

What causes the need for damping in a speaker? This Wikipedia entry explains it quite well:

Speaker diaphragms have mass, and their surroundings have stiffness. Together, these form a resonant system, and the mechanical cone resonance may be excited by electrical signals (e.g., pulses) at audio frequencies. But a driver with a voice coil is also a current generator, since it has a coil attached to the cone and suspension, and that coil is immersed in a magnetic field. For every motion the coil makes, it will generate a current that will be seen by any electrically attached equipment, such as an amplifier.

Bass drivers are a resonant system. In the same way that a car's suspension is a resonant system. We have a sprung, damped mass in both of them. With huge differences in the mass, spring rates, damping, input forces.

In a car you have the mass of the car, suspension springs, shock absorbers (dampers) as well as spring and damping effects from the tyres, suspension bushes etc.

With a bass driver the mass is in the moving part: the cone (with attached dust cap and voicecoil). The spring and damping effects are provided by the cone surround, the voicecoil connecting wires, the air in front of and behind the cone and the electrical damping effects.

Resonant systems can be either under, over or critically damped.

For a bass driver, one tenth critical damping would be bad. Too much flippy flappy unwanted cone movement. Overdamped would be bad. Too much pushing through treacle effect. The bass cone would be too slow and ponderous when reacting to the transient inputs that are such an important part of music.

It's when we get to the area of one half critical damping to critical damping that we have a big fat compromise in bass drivers. We have a trade off between accuracy (critical damping) and transient response (one half critical damping). As we increase damping towards critical we are increasing the pushing through treacle effect. That's something we don't want as the bass cones will then be slower and less free to move. As we reduce damping away from critical that's something we don't want as after a transient - eg the hammer hitting the skin of a bass drum - the cone will continue to produce sound at the cone's resonant frequency when we don't want it to.

If we have a bass driver that already has the best compromise amount of damping from mechanical means, adding more electrical damping would make it sound worse! IE active with solid state amplification would sound worse than passive with valves.

With a speaker, the greater the cone movement, the greater the tension we're going to put into our "springs", the more it's going to want to oscillate, the greater the need for the correct amount of damping.

Looking at this calculator: http://www.baudline.com/erik/bass/xmaxer.html

The amount of cone movement depends on the cone diameter squared, for a given frequency and volume. So that:

A 12" driver will move 4 times less than a 6" driver.

A 15" driver will move 6 times less than a 6" driver.

Twin 12" drivers will move 8 times less than a 6" driver.

A 30" driver will move 25 times less than 6" driver.

I'll use a car analogy here to illustrate the difference between a 30" driver and a 6" driver. Imagine 2 cars rolling down your driveway at 3 mph. The cracks in your drive are the musical signal, the car is the speaker. The first car is your car. At 3 mph on your drive you could take the shock absorbers out of your car and you wouldn't notice any difference. The second car is a one twenty-fifth (1 25) scale model of your car. If you put Barbie in the seat of this car imagine how she'd be rattled about as she was pushed down your drive.

Going active is a solution to a problem that has been created by using 6 inch drivers instead of something much larger.

More to follow...

 

[lpv]

would be interesting if Mr Ashley James could step in and comment on that?

btw.. what set up you have lindsayt?

 

[lindsayt]

...the 6.5" mid-bass driver of the AVI DM10's cross over to the tweeter at 2000hz.

As this chart shows: http://www.liutaiomottola.com/formulae/freqtab.htm the mid-bass driver is covering the lower 7 octaves of the audible frequency spectrum, whilst the tweeter is covering the top 3 octaves.

That's not a very equal division is it?

The mid-bass unit of the AVI's is too small to properly reproduce the lowest octaves.

For the frequencies from about 800 hz to 2000 hz the mid-bass cone in the AVI is heavy. It has too much inertia. There are other speakers that use a much lighter cone or dome for those frequencies.

 

[lindsayt]

And then there's the cabinet of the AVI's. It's ported. From about 100hz downwards most of the sound that you hear from these speakers will be coming from the port and not from the cone.

The cone basically produces sound by responding to the electrical signal sent to it from the amplifier.

The port is not connected directly to the amplifier. It produces sound by the air resonating in it.

Ports are poor at properly reproducing transients.

Some speakers don't have ports.

 

[lindsayt]

would be interesting if Mr Ashley James could step in and comment on that?

btw.. what set up you have lindsayt?

I think it's far more important what YOU think of what I've said than Ashley James.

You're quite welcome to tell me whay you think of it. Or you can keep that information to yourself if you wish. I don't mind either way.

What I would like to do though, is to encourage you to think for yourself, make your own decisions and plough your own furrow.

I'd rather not tell you what I have as that would tell Mr James the answer to a question I asked way back in post #31 on page 2 of this thread. A question that, so far, he has not answered.

 

[lpv]

do you want me to take a closer look at tech/ physics/ construction side of DM10s?

btw.. I did aks you few days ago on which forum I can send you pm?

 

[lindsayt]

Hi-fi subjectivist would be best. pfm and wigwam would be OK too.

 

[Ashley James]

http://hddaudio.net/bb/viewtopic.php?id=65

What makes Lindsayt look a total ass and I apologise for being so blurt, but I think I've taken more than enough from you when I haven't been able to respond to justify responding now, is that immediately you hear DMs, you can hear the massive difference in control. It produces headphone like clarity, or rather it along with very steep crossover filters and a few other things.

What is even more infuriating about you is that you announced that you'd heard one of the range and didn't like it because it sounded too lean. Well yes it would sound more lean than you're used to because the cones are better controlled.

Some years ago a scientist from Siemens, not an AVI owner, just someone who enjoyed research, did all the maths and computer modelling and posted it on here. You immediately swigged the cool-aid, went into denial and cooked up some pseudo scientific rebuttal and AE banned him. A very clever man with no axe to grind clarifying an important point.

Luckily he shot over to our forum and posted it there, so I can provide a link. Sadly the graphs have gone, but the important point is that whilst the resistance of passive components does affect damping adversely, the real damage is done by the action of the crossover. It progressively disconnects the driver until there's almost no damping at all.

 

[jcbrum]

ROFL

JC

 

[jcbrum]

Proper propogation and distribution of sound, leading to realism and good imaging, is best obtained by something approaching a point source. Not something a yard across.

JC

 

[lindsayt]

Ashley, your speakers sound lean because they are lean.

You are again coming out with misleading statements for marketing purposes.

The specification you use on your own website indicates that the DM10's are -6dbs at 50 hz.

That will make them sound lean compared to speakers that are -0 dbs at 40 hz.

The bass from your speakers is not well controlled below 100 hz. It's coming from a port!

Calling me a total ass is a personal insult. That is against Rule Number 1 from here: http://www.whathifi.com/forum/hi-fi/house-rules

Why do you think you're entitled to break the highly sensible What Hi-fi Forum rules?

You forgot to mention, that I reported that your speakers suffered from some compression as well as sounding lean. Some people will like that presentation. Some won't. I certainly don't.

You have not responded to a single point that I made in my 3 relatively long posts where I discussed the major flaws in your speakers. I tried to put it in easy to understand laymans terms. There is nothing "pseudo scientific" in what I said there. It's all based on sound engineering principles.

You calling me an ass and claiming that I cook up "pseudo scientific" statements is just your attempt to undermine me for your own marketing purposes.

You are welcome to see if you can find genuine fault with anything that I've said in this thread. I bet you can't.