I thought the adm40's did have a high pass filter set at 100hz when you use them with the avi sub.
There is, and there was meant to be a matching low pass filter for the sub (originally it was going to be in the ADM40s) but this plan was shelved when users discovered a sub added nothing useful. The AVI sub does have a selectable 100Hz filter but apparently this is not accurate enough to do the job properly.
There have been suggestions that a new 12" sub may be produced in the future. Perhaps the 100Hz filter will be included in this.
Main: SqueezeBox Classic>AVI ADM40
Second: SqueezeBox Touch>AVI ADM9RSS
Dont digital filters have their own problems?
like what? if you know of any why don't you share your wisdom?
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Which might lead one to suppose that AVI have decided against it for a good reason.
I wonder what good reason that may be? because I can't think of any. maybe except for cost cutting.
However, in my experience, few of the hi-fi subs that I have seen and used apply high pass filtering to the main speakers. There was a thread on here recently where someone wanted just that, in order to improve the power handling of his main speakers.
I had a look around and ended up suggesting the Adam subs which have an 85hz filter for the mains. This may still be common in some models but the more obvious brands I tried did not have it.
well, I didn't find it so difficult to find subs with high pass output. many USA sub making brands include it. especially the more obscure ones.
on the other hand, powered subs have been around for so long that it really makes it hard to understand why hi-fi manufacturers didn't come up with an idea to include sub xover in preamps/integrated amps by default. especially since so many pepople report so many problems with integrating a sub into a stereo set-up.
oldric, I understand the points you make concerning the mid/woofer driver in the ADM9s, but in practice they are designed to accept a full frequency signal without distortion. That is the reason why they operate perfectly satisfactorily in stand-alone (without sub) installations, and have very low distortion characteristics.
The design of the driver / cabinet / port is optimised for this performance, without forcing an unatural bass response. Consequently, they naturally fall off in bass response below 50 - 60Hz. This suits many styles of people and music, and is commensurate with the size requirement. The RS models, particularly the currently fitted new drivers, are exceptional in this respect.
If an extended bass response down to below 30Hz is required, or if bass emphasis is required, say by a particular music style, or LFE, then they may be augmented by use of the matching sub. Neither the mains, nor the sub, suffer from distortion by this approach, and the crossover effect is entirely acoustic, since no electronic crossover effects are present (between the mains and the sub), and provides the extra facility of adjustable extended bass response to suit room environments.
It's probably the best way to do it, really.
It's not my wisdom, just stuff freely available on the web. I assumed you would know about these things but I guess appearances can be deceptive.
Wouldn't there be any advantage in filtering out the frequencies below about 40Hz on the ADM's as they won't be making any noise that deep anyway?
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of course it is. and Mr Linkwitz propably got it all wrong in the end. after so many years experimenting with different 3-way dynamic drivers speakers he concluded that what he wanted to achieve was only possible in a 4-way guise. obviously he must have never visited AVI audio web site because he then would know that the ultimate audio nirvana can be found in a 2.5-way system!
Phileas, you're so lame. I don't know why I even bother to reply. show me a proof of your statement if you can. I can easily show you white papers backing up my statements; hint - IIR vs. FIR powered with ARM.
oldric, I understand the points you are making and I'm familiar with Linkwitz work.
There really isn't any need for so much sarcasm in your remark. It has sufficient merit as an argument not to need it. In fact such sarcasm suggests an over defensive attitude on your part, perhaps brought about by concealed insecurity.
Linkwitz's approach, and solutions, are indeed somewhat different to Martin Grindrod's work. I don't consider them to be better, or more domestically acceptable, even given the differering environments.
I personally do not accept that a 4-way driver system, complete with all the necessary complex crossovers and electronics does do a better job, and cost can be a consideration too.
The AVI products are relatively simple, long lived, and affordable, yet comprise everything necessary except the source. They employ very sophisticated drive units, and produce truly excellent sound quality.
No, I don't think so . . . .
a) they are designed to accept a full frequency signal, and reproduce it, as a stand-alone pair. They do this very well.
b) if, as you say, they don't make any noise below 40Hz, then why bother to filter it out ? - you can't hear noise that isn't there !
c) in fact they do produce sound at or below 40Hz but it is in fact fairly quiet, but not distorted. The function of the sub is to produce a louder bass signal.
I agree, and disagree.
It depends on volume.
The ADMs are better than most I have heard at simply "not playing" the low frequencies. However they aren't perfect. I can quite easily upset them if I go a bit crazy with bass heavy music, at volumes they reproduce perfectly at 50Hz and up.
It isn't an issue, as those volumes are rare, but I do believe a well-designed filter would be beneficial.
As fo roldric_dandruff.
“Out beyond ideas of wrong and right, there is a field.
I'll meet you there."
So you're an expert on digital filters but unaware of any problems with them?
Do you always have to suggest that anyone not agreeing with you is mentally either deficient or feeble?
'And so on February 22nd 1966, at Luton airport...'
And some on this forum are debating why the forum is no longer up to much. You spiny, oldric and many many more are why this forum, sadly, is going from bad to worse. You and your cohorts spew out the same bile at every opportunity and people are obviously fed up to the back teeth with it.
The trouble for you all, is that the AVI system just works. It produces a disproportionately excellent sound for the money and [often thanks to your cohort] more and more people on here have found out the truth and now happily live with their AVI products.
If you and yours could just grow up a little, even possibly experience the things you all so readily criticise, then the forum would be a significantly better place. If I were a company spending good money to advertise here, then the pathetic antics of so many of you would ensure my money moved elsewhere.
AVI have created domestically acceptable, superb sounding, excellent VFM products. Get over it.
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