This phase thing

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andrew Ivimey
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#31 Re: This phase thing

Post by andrew Ivimey »

Hi Scott, don't defer at all. It's over three years now since I did any tests that relate to this. I'm a) rusty and b) I've forgotten much.

Need to re-read...maybe later though.The weather is stunningly beautiful - tomorrow too hot.
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#32 Re: This phase thing

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You still know (a lot) more about it than I do Andrew. ;) There's a bit more here under Duplex, albeit they've used 1KHz - 1.5KHz as the transition zone rather than 700Hz - 1.4KHz https://en.wikipedia.org/wiki/Sound_localization I imagine Wikipedia isn't cutting edge, but presumably is still reasonable in a broad sense. I think Toole has some references also, although it's been a while.

Too right. I just wish I could get out and enjoy it!
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#33 Re: This phase thing

Post by IslandPink »

You do know that lack of vitamin D results in poor resistance to infections, Scott ? :)
pre65 wrote: Sat Apr 08, 2017 3:17 pm The second tone now seems a tiny tad less loud, or perhaps less sharp.
This is a good point because having a phase error across the band of a speaker makes is sound quieter. At various stages with the OB's and the bass/mid horn in my project I've had poor crossover choices or poor loading or back-volume on the horn driver, and you find your self not just with a soft and toneless sound, but also turning up the amp by anything up to 3dB.
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#34 Re: This phase thing

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I'll cover up. ;)

Right, or through the transition band at any rate.
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Thermionic Idler
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#35 Re: This phase thing

Post by Thermionic Idler »

I haven't done the tests yet but I've seen a lot of to-ing and fro-ing about phase coherence of late. Now Meredith is quite a devoted collector of 78's and we were down in Birmingham today picking up another lot (along with a visit to the Diskery - the oldest record shop in England and well worth a visit, came away with a nice haul of LP's from there too).

With the help of young Cressy we now have a means of playing 78's, though I think performance will be further improved with a cartridge that's actually wired for mono. Anyway, the point being, I have been wondering to myself, what is it that makes so many of these old 78's sound so GOOD - despite them being rubbish in hi-fi terms. Most have a huge amount of hiss and crackle, the response doesn't go beyond 8k, and a lot of them have suffered groove damage from worn out steel needles.

But - and here I make reference to Dr Honeydew - filters filters filters. How many filters were in the signal chain when these things were recorded? Most were done electrically straight to hot wax - pre-1920's were entirely acoustic of course. And they sound fantastic because the phase hasn't been mucked about with. Just warm and musical. Kind of a light bulb moment.

Anyway - just a bit of G&T-powered blather but I thought it was vaguely relevant. :)
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Dr Bunsen Honeydew
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#36 Re: This phase thing

Post by Dr Bunsen Honeydew »

I have answered Moose question but he doesn't understand my answer, as it is to do with ears hearing what you here are exploring, and that old post about his projects has degenerated into just eeediots responding.

I am still here I don't flounce, but if the flea and his buddy follow here to continue it I will *try* to ignore them.

OK my offer of a three way split stands. Cheap as chips Chinese drivers I have listed, just baffle boards. I will make one with just protection on the tweeter and doping on the bass/mid, and I hope we have voluntary making of one with standard 1st order filters and one with standard 2nd order filters, and lets put this to bed with music.
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#37 Re: This phase thing

Post by pre65 »

If the method you advocate was to "win" on this challenge, surely it would only be valid on that particular driver ?

I don't see the challenge taking part as the result does not necessarily prove the point either way, the only beneficiary would be the Ebay seller.
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#38 Re: This phase thing

Post by Daniel Quinn »

pre65 wrote: Sun Apr 09, 2017 5:21 pm If the method you advocate was to "win" on this challenge, surely it would only be valid on that particular driver ?

I don't see the challenge taking part as the result does not necessarily prove the point either way, the only beneficiary would be the Ebay seller.
The drivers would not be sufficiently unique to negate any and all generalisations possible . And anyway the point of complex crossovers is to control driver units within the specified operating parameters { which it is argued does not effect the music}

Thus as a test of the issues , mechanical versus passive electrical control of drive units , cheap drivers are an ideal subject.
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#39 Re: This phase thing

Post by pre65 »

Well Dan the man, as Richards love child you are duty bound to take his side. :lol: :lol: :lol:
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#40 Re: This phase thing

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take his side
Still in the playground then?
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#41 Re: This phase thing

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Nick wrote: Mon Apr 10, 2017 5:43 pm
take his side
Still in the playground then?
Humour Nick.(LOL)
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#42 Re: This phase thing

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I don't think anybody would argue that complex crossovers do not affect 'the music'. Crossovers are there to manipulate the behaviour of the drive units in a desired way, ergo they all have an influence on signals that pass through them, just as a phono-stage, CD player, preamp, power amp and of course the speaker drivers in their turn affect the signal in the same or similar ways.

What seems to be forgotten though is that, assuming an element of design actually exists, a well-designed crossover is as simple as possible to do the job required of it, i.e. to achieve a specific goal or goals. A well-designed crossover that happens to be 'complex' (whatever definition you may have for that) is complex because that's what it needed to be to do the job desired of it. There is no other purpose for it to be so.
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#43 Re: This phase thing

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Scottmoose wrote: Mon Apr 10, 2017 6:05 pm 1. ...just as a phono-stage, CD player, preamp, power amp and of course the speaker drivers in their turn affect the signal in the same or similar ways.

2. A well-designed crossover that happens to be 'complex' (whatever definition you may have for that) is complex because that's what it needed to be to do the job desired of it.
1. Yes but errors in amps, phono stages, CD players etc can be reduced to levels an order of magnitude below the typical problems with speakers. With speakers you need to think hard and talk realistically about the compromises.

2. I think the general listener and speaker 'dabbler' doesn't always realise what the experienced speaker designer has decided to take as the set of targets for his loading and crossover, and what the implications of those choices are. If we talk about your Dungeon keeper, that's OK as I assume you had a good steer on the aims of that project from a customer. If it's advising people here, I think there's a tendency to use 'industry standard' advice which may suit the home listener quite poorly. For instance, let's take the old chestnut of a ribbon tweeter. You may make the unilateral decision to put on a 3rd or 4th order high-pass on there to make sure the ribbon can handle close to it's spec power rating ( which may be 60W for instance ). Now, this ribbon may be 95db/w and the user is very happy feeding it with an 8W 300B amp running at less than a watt. What you decided re. power handling has ensured that the female vocal tone from this entire loudspeaker is screwed up, because all the higher harmonics are now 180 deg or 270 deg out of phase with the fundamentals. This is not always at all clear from some of the discussions that go on. I think they key phrase here is 'well-designed' - and how that means different things to different people. And ps. I certainly am not singling you out for criticism here ! - the DIY Audio forums are full of much less nuanced advice than you are able to give.
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Dr Bunsen Honeydew
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#44 Re: This phase thing

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At last - perhaps you will be listened to.
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pre65
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#45 Re: This phase thing

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Dr Bunsen Honeydew wrote: Mon Apr 10, 2017 7:15 pm At last - perhaps you will be listened to.
If you mean Scott, he has always been listened to, apart from you that is.
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