Active Speakers

[johnb]

I think Bob Stuart of Meridian would be a little hurt if you called his DSP speakers a "modern radiogram"!

[Gordon]

I believe rather a lot of recording engineers use active speakers.

I believe that Abbey Road uses, among others [see here for a list of what they can offer, scroll down to LSs] B&W Nautilus Diamond 800Ds as their main monitors - I don't believe they are active, I can't find a spec but I've seen one somewhere that showed the crossover and the connections at the back for bi-amping etc.. I was in AR last March and they had them in S1 then doing a film dub. Bit pricy mind you!! Talk about big and heavy.

Look here

http://www.bowers-wilkins.co.uk/Speakers/Home_Audio/800_Series_Diamond/explore.html

for the description etc and down the bottom for the AR comment/endorsement. Browse the site for more and here

http://www.bowers-wilkins.co.uk/Discover/Discover/Technologies/Crossover.html

for some stuff on crossovers. It'll warm your heart, lots of tweaking by ear.

Yes, #46, I think Bob would have his ears burning!! Try googling for some of his writings, I'm sure I've seen one about Active Speakers. It's probably an AES paper you may have to pay for though.

[clive heath]

..but surely there is no alteration to amplitude or phase that cannot be made by inductances and capacitors
a)applied to individual speakers in an active speaker enclosure where the signal is the order of volts
b)involved in the post or pre active-crossover part of the low level signal let us say millivolts.

In any case phase linearity is the key and is near impossible with an active crossover based on LC combinations.

[Nevalti]

Excuse my ignorance but I didn't know you could tune passive speakers themselves. You can modify the signal sent to the speaker system with a graphic equaliser (analogue or digital) but that applies to all speaker systems. What am I missing?

You can use different amplifier(s), pre and power if you desire, different interconnects, different speaker cable, different cross-over or components, different DACs (some active speakers include DACs). If desperate, you could change the internal wadding, wiring, drivers, port choking etc but you can also do most of that with active speakers. The main point however is that you have no upgrade path with active speakers - so you need to be pretty damn sure you will be prepared to live with them as long as their price demands you to. To make matters worse, some popular active speaker manufacturers NEVER allow their wares to be sold via shops where they can be compared with other equipment. You just have to trust them or do your comparisons at home and then send them back.

If you use a graphic equaliser or any other form of signal processing, you are more likely to degrade the sound than improve it - same with tone controls and 'loudness' buttons etc.

One last point - high quality hifi equipment has a very healthy second hand market. This enables you to sell without losing a fortune or to buy without paying full price. If you both buy and sell S/H you can make the trade effectively 'free' to experiment to your heart's content without it costing more that the cost of the fuel to collect your new toys. I have not studied the market for S/H active speakers but my betting is that their price falls through the floor - for the very obvious reason that they are not upgradable. For anyone uninterested in achieving the best sound, they are of course very sensible.

[Phileas]

For anyone uninterested in achieving the best sound, they are of course very sensible.

How absurd.

[Beef Oven!]

How absurd.

I didn't swallow that bird either.

[clive heath]

Your main point in this reply (#49) is that "you have no upgrade path" which is not the same as claiming that you "cannot tune active speakers". Well you have some control if you build them yourself. I agree about equalisers and to a lesser extent tone controls but the degree of degradation gets us into the "golden ears" discussion, a wasteland. Can I make my main point again. With my separation circuit, if you look at the outputs to tweeter and woofer from the pre- or power amps on a two beam oscilloscope the two wave forms are exactly the same amplitude and in phase at the crossover frequency as you increase or decrease the frequency while the amplitudes change appropriately the waveforms stay exactly in phase. You do not get this effect with LC crossovers. You can also build in a gain adjustment to the tweeter to allow balancing the output of the two speakers at the crossover frequency to match them given that they will almost certainly not have the same volts to db ( i.e. efficiency) characteristic although you have to hope they are linear phase over the crossover region but then that is true of all speaker systems.

[Beresford]

[QUOTE=jayne lee wilson;364197]

Earlier this year I was a goner for 24-bit downloads, I was planning major changes to bring them in en large. But the purchase of a 2ndhand DAC (T&A DAC8 replacing Cambridge DACMAGIC) made CDs sound so good I lost interest in the files...

Similar experience. When upgrading from LP's, I thought Hi res downloads would be the only way to improve on my MF Electra E600 CD player + Sumo DAC. But instead I bought a battery powered USB DAC (JKDAC32), and played the ripped CD's through a more-or-less dedicated little windows 7 laptop, using Foobar and the wonderful JPLAY software. It was so much better than the original £600 CD player, most noticeably on piano and strings. I now consider that most of the shortcomings of CD's were down to the replay system. Sure Hi-res is better (try the 2L site), but not much. So the CD's have a new lease of life (except for some early ones where the CD and the download were equally flat and MP3 like, and my own home-digitised LP versions were much better). Maybe a new thread on this topic?

The Australian Note-Perfect semi-active speakers have an interesting approach - I would love to hear them.
noteperfect.com.au

[Nevalti]

I think Bob Stuart of Meridian would be a little hurt if you called his DSP speakers a "modern radiogram"!

Yes, it is difficult to make a point without upsetting someone. Meridian do make some excellent 'radiograms'.

I have yet to hear their top of the range speakers but for £35,000 you would rightly expect them to be pretty damn good. In all probability they were a tad disappointed when the Stereophile reviewer said,

"While I could adjust the HF control to ameliorate the somewhat shut-in highs, the mid-treble balance was always a little on the forward side. While this added to the impression of detail and clarity, it was at the expense of a slightly relentless quality.........."

The point made earlier was that you can 'tune' a system with separate components if you so desire. I think I would be more than a little bit disappointed if I had spent £35,000 on those speakers and found that I didn't like the sound after all - and there was nothing I could do about it. You could of course buy Meridian's upgraded version (coming out this year) instead in the hope that they would suit you better. I wonder what the new ones will cost? £45,000?

I wonder why they are upgrading their perfect speakers already? We must assume that they weren't perfect after all. Are they upgrading the amps, the DAC, the drivers? What a shame the owners can't do that to their outdated ones.

As for depreciation, I found a second hand pair on Audiogon which had dropped 70% from their original price. You obviously need to be pretty rich to invest in them. I wonder how good a S/H separates system we could put together for £35,000 .... and get the money back afterwards.

[Nevalti]

Browse the site for more and here http://www.bowers-wilkins.co.uk/Disc...Crossover.html
for some stuff on crossovers. It'll warm your heart, lots of tweaking by ear..

Above a certain level of accomplishment, 'tweaking by ear' is the only way to improve. It doesn't matter how badly something measures if it sounds right.

[jayne lee wilson]

About the only actives that hold up well across the 2ndhand marketplace are ATCs. I admired them hugely when I trialled them for a few weeks, but ended up rejecting them for being a little... relentless. Well, very forward at least. But the same amplifiers that were used in those ATC ASL50s, in the guise of the ATC SCA2/SPA2-150 have been resident here now for several years driving Harbeth Compact 7IIs. Heaven.

[Gordon]

Above a certain level of accomplishment, 'tweaking by ear' is the only way to improve. It doesn't matter how badly something measures if it sounds right.

I'm not sure you really mean that. So, in the spirit of curiosity, coming from the standpoint of a simple engineer [we are you know] let me be very clear and understand this:

Let's say that an amplifier's frequency response measures 60Hz to 15kHz +3 dB and the response wanders around in a peculiar way in that range, just as this spec allows. Some would say that measures badly, meaning it's not very good. Why? Perhaps because the resulting product sound is highly variable in production and we want more uniformity. Might "it" sound right though? Which "it" do you mean? Of all the variable "its" there could it be, there is only one that "sounds right" but the others do not? Well, yes, it might to some, especially if there is a rise around the 3 kHz point. Or is it that ALL of them, regardless of the tolerances, do? That would be good wouldn't it? Let's suppose though that there is only one we can find that does "sound right" then.

If we were to tighten that spec up a bit and get the same amp's production line to meet 30 Hz to 18 kHz +1 dB. Would we get far more of the production to "sound right" as before? Would that also mean that the amp we chose before now sounds even better or might it actually sound worse? IOW by making it measure "better" it may not necessarily sound better because what we have done in changing the FR has altered something else too and it was that that made it sound right in the first case. Do we imagine that engineers are that stupid?

Applying this inquiry to a B&W speaker, when you say "it" you mean "it" to be the speaker and "sounds right" means it does so to your ears? Would that be what you mean?

If so, would you accept that some other people might not agree?

In the context of that link I gave to B&W and their approach to their flagship product, can we agree that the speaker sound may be altered audibly by changing a particular component in its crossover, for example an inductor, a coil of wire? Nothing else.

Can we also agree that the properties of the inductor required have been arrived at somehow in the first place? For example, someone on the B&W team has examined the drive units etc etc and come to a decision about those properties of that particular inductor and in particular it must have an inductance of say 523 mH for the sake of this question? A bit of "Proper Design" has to go on to get that value.

If we changed that inductor value to say 533 mH instead would anyone hear it? Don't know let's have a listen. Turns out no one can hear a difference. So now we ask what if it's 513 mH; again listen, again no one hears anything. Conclusion? Might it be that the design can tolerate a variation of about +2% in that component value, even though the actual "correct design" value is 523? IOW the right sound is a range of responses not a precise one and it corresponds with a known range of component value measurements. It sounds well because it has been measured well??

Now let's swap the main drive unit for another one of exactly the same type from the same production batch. Put it in the speaker. Will we hear a difference? Let's say we do - what has happened to the "right sound" we had before? Has it got worse or better? Let's say we prefer it. What do we do with the 523 mH inductor now? Perhaps we find that the 513 mH we couldn't hear before is now audible and we don't like that sound. In fact this speaker requires the 2% tolerance to be between 522 and 542 mH a shift of 9 mH. What do we do on the producion line? Well perhaps there isn't one, each speaker is hand built [that could be why it's so expensive?] with each component being selected to get the response to "sound right" in each and every case. We don't want any Friday Afternoon products in this company thank you. Other companies can just assemble their products from set pieces and accept the variations that result. Some of them might sound right to good ears but others may not. ALL ours do because we tweak and why wouldn't you.

Let's keep it simple and pause here before moving on, perhaps later. It's been a long day and the Dalwhinnie awaits.

Oh, BTW an inductor has resistance too and may have a ferrite core that has to tolerate large and small currents. At 50 Hz the inductance is indeed 523 mH but at 1200 Hz.... Oh dear.

[Nevalti]

I'm not sure you really mean that. So, in the spirit of curiosity, coming from the standpoint of a simple engineer [we are you know] let me be very clear and understand this:...............

..............................Applying this inquiry to a B&W speaker, when you say "it" you mean "it" to be the speaker and "sounds right" means it does so to your ears? Would that be what you mean?

If so, would you accept that some other people might not agree?...................................

A long question, greatly edited by me but I think your main point is, 'what is right'?

Yes, I was not very precise in my statement. I am well aware that others may not agree with my view of what is 'right' but I obviously don't see that as reason not to express my views. It astounds me what some people think sounds 'right' and possibly my view will astound them but I am also well aware that most people have not actually listened to top notch equipment and have some strange ideas based on God knows what. I am also aware of some people who go to a lot of trouble with their selection and end up with something sounding very different from what I think sounds right. I remain adamant that people should base their opinions on experience rather than received wisdom and theory. I seek to get a sound as close to 'realistic' - (a dangerous term, I know) and I always attend a live concert immediately before auditioning any new equipment to get my ears 'in tune'. I accept that my audio memory may not be reliable but some people literally have no idea what live music sounds like.

Although I seek 'realistic' (see above) I am perfectly happy listening to a system which I know very well is flawed providing it has some other redeeming characteristics; FM for example! Valve amplifiers are another good example - they tend to have relatively high distortion and poor bass dynamics but they often make up for that with beautiful voice reproduction and effortless detail which is not shoved in your face with leading edge emphasis. Similarly I can enjoy listening to the old BBC LS3/5As. They were deliberately engineered NOT to be accurate but to sound pleasing - it works for me but not for plenty of others.

On reflection, I should have said that it doesn't matter what it measures like, as long as it sounds pleasing to the owner. I do accept that you will never please everyone. The negative comments above about the mega-bucks active speakers seem to prove that. There, conscientiously brought back on-topic in the penultimate line.

[Gordon]

A long question, greatly edited by me but I think your main point is, 'what is right'?..........On reflection, I should have said that it doesn't matter what it measures like, as long as it sounds pleasing to the owner. I do accept that you will never please everyone. The negative comments above about the mega-bucks active speakers seem to prove that. There, conscientiously brought back on-topic in the penultimate line.

I will refrain from further comment although there is much to say. In my last post I was a bit OTT in verbosity because I wanted to ask the same question more than once; in this thread and others words and their meanings were getting in my way. At last I think I understand your position and have a great deal of sympathy with it. I suspect we will not choose the same sound!!

I have a good friend whose system is quite a puzzle to me because it sounds rather harsh and "in your face", as you put it. He's happy so why should I worry? He thinks my system is "bland" but I believe it is actually rather more realistic. Like you, I like to keep my ears more or less up to concert pitch. I think he wants to be punched - as it were!!

[johnb]

As far as people's audio systems are concerned I suspect there is a large degree of pot luck in the way many (most?) people chose them or build them up. I also suspect that most people aren't that good at auditioning components (e.g. what is initially impressive might seem less so over the long term) and once they have bought a system they get used to it and learn to like it.