Avi sub. Now reunited with ADM9RS...short bundle of thoughts

[oldric_naubhoff]

and the sub has a variable (not simple) low pass filter, controllable both for level and frequency response

actually this is a simple low pass filter for a sub in that way every other sub on the market will be supplied with at least similar solution to help blend the sub with the rest of the spaeker system. variable lowpass filter and gain control are an absolute minimum in a competent sub so as you see AVIs here don't do any extra work over what's required.

some more capable subs would have parametric EQ implemented to help smooth out rooom nodes. some even more capable subs would be DSP controlled in order to virtually eliminate room nodes. this is what could be caled "not simple" xover.

 

[Phileas]

what's not to like about DSP contolled speakers?

Dont digital filters have their own problems?

 

[Phileas]

I was realy amused when I found out that AVIs don't use any highpass filtering on their mains. since they are already active and controling unit is implemented in one of the mains I would have imagined that by slightly modifying the xover it's silly easy to implement high pass for when the ADMs are used in sub-sat system.

Which might lead one to suppose that AVI have decided against it for a good reason.

 

[davedotco]

I was realy amused when I found out that AVIs don't use any highpass filtering on their mains. since they are already active and controling unit is implemented in one of the mains I would have imagined that by slightly modifying the xover it's silly easy to implement high pass for when the ADMs are used in sub-sat system.

Which might lead one to suppose that AVI have decided against it for a good reason.

This is quite true, The Dark One has spoken at length about it.

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.

 

[jiggyjoe]

I thought the adm40's did have a high pass filter set at 100hz when you use them with the avi sub.

 

[jiggyjoe]

I would opinion that the boom with the AVI's minus the sub, would be due intermodulation distortion..

...active ones with DSP which deal most elegantly with all the phase and crossover issues that the head salesperson on that 'other' forum would prefer to otherwise gloss over....

There's no crossover to the sub so intermod distortion is unaffected by its presence.

I would suggest boom problems are quite rare with AVI actives.

I also don't share your confidence in the ability of DSP to deal with all the crossover issues.

fortunately vast number of electrical engineers do share JMac's confidence in DSP controlled speakers. thanks to DSP more speakers appear on the market which despite the fact they are multiway jobs they show school-book step response behaviour. this is only achievable for a single full range driver speaker or a multi-driver speaker with perfectly time-aligned drivers. you could achieve similar performance with an analog xover (passive or active) too but doing these things in digital makes the whole job much easier and the end results are virtually free from variations induced by quality of analog components.

on top of that you get full control over speaker frequency response limited only by capabilities of used drivers and unmatched control over driver movement which is proved in impuse response test by means of better suppresed driver ringing. and if you could get DSP speakers with digital inputs and digital power amps (like in case of Grimm Audio's LS1s) you get the benefit of keeping the signal in digital domain as long as it's virually possible, which will always be a good thing.

what's not to like about DSP contolled speakers?

The only fully dsp speakers I have heard were meridians 8000's i think, and I must say I found them a bit meh!

 

[Phileas]

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.

 

[oldric_naubhoff]

what's not to like about DSP contolled speakers?

Dont digital filters have their own problems?

like what? if you know of any why don't you share your wisdom?

 

[oldric_naubhoff]

I was realy amused when I found out that AVIs don't use any highpass filtering on their mains. since they are already active and controling unit is implemented in one of the mains I would have imagined that by slightly modifying the xover it's silly easy to implement high pass for when the ADMs are used in sub-sat system.

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.

 

[oldric_naubhoff]

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.

 

[Phileas]

what's not to like about DSP contolled speakers?

Dont digital filters have their own problems?

like what? if you know of any why don't you share your wisdom?

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.

 

[jcbrum]

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.

JC

 

[steve_1979]

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.

JC

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?

 

[oldric_naubhoff]

It's probably the best way to do it, really.

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!

 

[oldric_naubhoff]

what's not to like about DSP contolled speakers?

Dont digital filters have their own problems?

like what? if you know of any why don't you share your wisdom?

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.

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.

 

[jcbrum]

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.

JC

 

[jcbrum]

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?

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.

JC

 

[fr0g]

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?

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.

JC

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.

"yawn"

 

[Phileas]

what's not to like about DSP contolled speakers?

Dont digital filters have their own problems?

like what? if you know of any why don't you share your wisdom?

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.

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.

So you're an expert on digital filters but unaware of any problems with them?

 

[spiny norman]

In fact such sarcasm suggests an over defensive attitude on your part, perhaps brought about by concealed insecurity.

Do you always have to suggest that anyone not agreeing with you is mentally either deficient or feeble?

 

[relocated]

In fact such sarcasm suggests an over defensive attitude on your part, perhaps brought about by concealed insecurity.

Do you always have to suggest that anyone not agreeing with you is mentally either deficient or feeble?

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.

 

[John Duncan]

Bit of a non sequitur there, if I might say...

 

[oldric_naubhoff]

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.

this is a very funny post so I take it your solution to cure forum's ills is to audition AVI speakers?! if you and your ilk are indication what happens to people after experiencing AVI products then I think I'll pass.

 

[oldric_naubhoff]

what's not to like about DSP contolled speakers?

Dont digital filters have their own problems?

like what? if you know of any why don't you share your wisdom?

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.

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.

So you're an expert on digital filters but unaware of any problems with them?

yeah, I thought so...

 

[oldric_naubhoff]

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.

JC

I was only trying to convey what I already found out from other designers, that 3-way is already pushing comort area of operation of drivers used to its limits therefore splitting the full range signal even more is not a bad idea since it's already well splitted. if the speaker is actively driven then aligning the drivers output shouldn't be a problem, as you know. as an added bonus in case of Linkwitz's 4-way design and Don Keele's 5-way design (another good example from a respected designer) you get a speaker that exhibits constant beamwidth dispertion. and that helps to conceal the speaker in the room.

and you're trying to convince me that AVI has sourced some 6.5' driver that for some reason is immune from breakup modes in the midrange and excessive THD in the bass? all the ill things that plague every other small speaker on this planet don't apply to AVI bookshelf speakers?

so now you should know what's causing my sarcasm. it's not any alleged conseled insecurity but your and others conviction of superiority of AVIs design