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Beyond Stereo to multiple Speakers

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Re: Beyond Stereo to multiple Speakers

Postby solotibia » Sun Oct 03, 2010 11:20 pm

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Last edited by solotibia on Mon Oct 04, 2010 5:15 am, edited 1 time in total.
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Re: Beyond Stereo to multiple Speakers

Postby solotibia » Mon Oct 04, 2010 12:11 am

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Re: Beyond Stereo to multiple Speakers

Postby pwhodges » Mon Oct 04, 2010 7:34 am

David,
You can use "code" tags (see the buttons above the edit box) to force display in a fixed-width font, so your original attempt would appear thus:

The notes are really generated by an interference process.
Code: Select all
Combining these two:
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
|  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
gives:
|     |     |     |     |     |     |     |     |     |     |     |     |     |     |

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Re: Beyond Stereo to multiple Speakers

Postby mdyde » Mon Oct 04, 2010 7:42 am

jkinkennon wrote:On another topic, I cannot resist the urge to point out that the spec being quoted for the Mackie speakers is not the spec for the speaker, which would be considerably higher, but the spec for the amplifier section of the speaker only. I don't question the quality or well deserved reputation of these speakers, but speakers remain the most non-linear of all the components in the audio chain.


Many apologies - my mistake. Mackie's spec. sheet for those speakers doesn't give a figure for speaker IMD after all:

http://www.mackie.com/products/hrmk2series/downloads/HR824MK2_Specs.pdf
Best regards,
Martin.

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Re: Beyond Stereo to multiple Speakers

Postby David Pinnegar » Mon Oct 04, 2010 4:13 pm

mdyde wrote:Many apologies - my mistake. Mackie's spec. sheet for those speakers doesn't give a figure for speaker IMD after all:

http://www.mackie.com/products/hrmk2series/downloads/HR824MK2_Specs.pdf


Hi!

Nice spec sheet.

They look very fine. The figures and graphs are very impressive. But when one realises as pointed out that the distortion figure is that of the amplifier rather than the whole product, one starts to realise that all is not all that it seems and there might be a bit of blinding by science going on. They will have been measured with very expensive equipment measuring to great accuracy in a nice anechoic environment but our ears are the best measure of the criteria that are being measured.

And are speaker response curves ever quite that flat and smooth? WOW! Probably the amps, again, rather than the speakers.

They might be what is commercially available, and very good for what they are made for, but I'm not greatly surprised that Joe is identifying something in the sound of his organ he can't quite put his finger on other than the fact that he has a suspicion he's hearing his speakers rather than his organ.

These speakers, as monitor speakers, are intended not to reproduce reality but to enable recording engineers to make a product that will sound good through the sort of speakers that their customers will be listening through.

http://www.wilsonaudio.com/product_html/alex_intro.html is interesting:
A sign that hung in Albert Einstein’s Princeton office famously put it this way: “Not everything that can be counted counts, and not everything that counts can be counted.” It takes wisdom and experience to know the difference, especially for a loudspeaker designer.


http://www.wilsonaudio.com/product_html ... ienna.html tells us that their speakers are inspired by buxom females and
http://www.wilsonaudio.com/product_html/alex_xover.html furthers in the same vein. It tells us that they have covered the crossover with epoxy to stop any electromechanical interaction - has anyone ever noticed such a problem? - and that it also hides their secrets!
http://www.wilsonaudio.com/product_html ... intro.html follows telling us about the succession of Royal families, comparing their speakers to the succession of Charles VI of France. I haven't seen a graph or a figure on that site but whether by figures or words, the marketing stuff can never really tell us how the respective products sounds or what programm material it sounds good on.

Best wishes

David P
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Re: Beyond Stereo to multiple Speakers

Postby Eric Sagmuller » Mon Oct 04, 2010 5:39 pm

David Pinnegar wrote:


And are speaker response curves ever quite that flat and smooth? WOW! Probably the amps, again, rather than the speakers.

They might be what is commercially available, and very good for what they are made for, but I'm not greatly surprised that Joe is identifying something in the sound of his organ he can't quite put his finger on other than the fact that he has a suspicion he's hearing his speakers rather than his organ.
Best wishes

David P


The monitors are adjusted to be + - 1.5 db from across the range they specify.

I didn't get the impression that Joe thinks he's hearing his speakers. The sound he was referring to as IM is actually a phenomenon related to the two different frequencies. I also heard this on my pipe organ. Unless you are referring to something else he had thought he heard.

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Re: Beyond Stereo to multiple Speakers

Postby pwhodges » Mon Oct 04, 2010 6:06 pm

David Pinnegar wrote:These speakers, as monitor speakers, are intended not to reproduce reality but to enable recording engineers to make a product that will sound good through the sort of speakers that their customers will be listening through.

I would say, rather, that many domestic speakers are not designed to reproduce reality as monitors can, but to soften the unpleasantness of both poorer recordings (of which there are very many), and untreated rooms with poor acoustics (virtually all).

In the pop field, engineers will check their mix using inferior speakers, and even in a car; classical recordings are commonly made without that compromise.

I would not consider using anything less than my ex-BBC monitors* at home, because I want to hear the sound coming out that went in, thank you.

Paul

* I should declare an interest, to the extent that I once worked at the BBC as a studio manager (= recording engineer). :D
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Re: Beyond Stereo to multiple Speakers

Postby David Pinnegar » Mon Oct 04, 2010 6:34 pm

Eric Sagmuller wrote:The monitors are adjusted to be + - 1.5 db from across the range they specify.


Hi!

Yes . . . well . . . um. Incredible.

The reality is that acoustic response graphs are _never_ that flat with no bumps here and there. The "Parametric Servo Feedback" should operate to remove IMD absolutely, but the raw physics of sound propagation cannot remove Doppler distortion, and looking at the circuit diagram, the feedback system only operates in the bass. So the tweeter is not artificially controlled and high frequency graphs simply _cannot_ be that flat.

Looking up Parametric Servo Feedback turned up the spec for SRM450 which makes it clear that the system enables better smoother bass to come out of a smaller box. Brilliant. But if one is running bass through this, if one is engaged in critical listening as we are in the organ reproduction realm, certainly this design pays no heed to Doppler effects, which certainly can insert sidebands to reproduced frequencies.

However, that may be one problem - but whatever the beauty of the straight line graphs or otherwise these speakers are of a common hi-fi genre which may be more suited to the nature of current pop music and provided people using electronic organs use such designs, pipe organs will be in no danger.

Without having auditioned this particular speaker, the specification is capable of being interpreted to tell us that this type of speaker however beautifully and cannily engineered simply cannot reproduce happily a Wurlitzer Trumpet stop and I'd predict that a Diapason might sound a tad plastic. If one is looking for a hi-fi virtual reality surround sound, in multiple numbers they'll probably make people very happy. *

Standing as an organ is a different matter, however and I have had personal experience of attempting the best possible match to a real instrument adjacent. The result is critically speaker dependant.

Best wishes

David P

* PS Paul - very sure that BBC monitors will be very nice at home. Through monitors we look at a perspective through to the sound sources, as if through a window at the instrument. But to _be_ an instrument in a space of its own, it is helpful to look at the perspective from the other end, from looking out from the instrument. I wrote about a formula to relate the size of an organ and area of speaking pipes to the area of speakers through which those "pipes" are speaking. At many times we're metaphorically happy to stand on the quayside and glimpse through the porthole of a cruise ship at the Wurlitzer inside, but we cannot expect the reverse for that instrument to _perform_ to the people on the quayside only through that porthole.

Similarly we might like to experience the representation of the memory of the foghorn at home but we would not want the foghorn in our home. So home users creating the virtual reality home cathedral environment with wet sample sets have different requirements to those creating performance instruments with dry samples.

My comments above relate to the latter use: speakers such as the MACKIE-SRM-450 are marketed for public address use but organ reproduction depends on associated but different design criteria. I am unlikely to say more than this in a public forum.
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Re: Beyond Stereo to multiple Speakers

Postby pwhodges » Mon Oct 04, 2010 7:10 pm

David Pinnegar wrote:The reality is that acoustic response graphs are _never_ that flat with no bumps here and there.

To illustrate this... I have what the designer (with decades of experience) considers the best mic in the world (within constraints I won't go into). The real (not marketing influenced) graphs of its various outputs in different patterns and at different angles are all combined in the following graph - flat it is not! I am not at liberty to identify the mic in association with these graphs, in case they should be misinterpreted by the ignorant.

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Re: Beyond Stereo to multiple Speakers

Postby Eric Sagmuller » Mon Oct 04, 2010 7:19 pm

I just looked at the HR824 graphs and what they are showing are not to represent the overall frequency response. They are just giving an example of how the different switches affect the response curve in reference to a flat line.

The bass driver is really not a servo feedback as such. It is a current feedback amplifier. And yes the tweeter amp is just a standard voltage feedback amp.

I have compared these to both Behringer B2031A's, B2031P's and the Audio Nirvana Super 8 full range drivers. And I can say they have a very neutral, flat frequency response in comparison. The AN's were very bad, even when heavily equalized, still had a nasal sound to them. They are a good example of a very non linear driver.

I'm talking about wet samples at near or mid field listening. Reproducing dry samples in a reverberant environment, one could probably use different drivers that might project one stop better than another.

Listening to the Bovenkerk stops on the HR824's, especially the 8' diapason, they sound absolutely lovely and real. Hardly plastic :evil:
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Re: Beyond Stereo to multiple Speakers

Postby David Pinnegar » Mon Oct 04, 2010 7:31 pm

Eric Sagmuller wrote:Listening to the Bovenkerk stops on the HR824's, especially the 8' diapason, they sound absolutely lovely and real. Hardly plastic :evil:


:-) Dear Eric

I did make the points:
If one is looking for a hi-fi virtual reality surround sound, in multiple numbers they'll probably make people very happy. . . home users creating the virtual reality home cathedral environment with wet sample sets have different requirements to those creating performance instruments with dry samples.

. . . so I don't think there is misagreement between us.

Best wishes

David P
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Re: Beyond Stereo to multiple Speakers

Postby toplayer2 » Mon Oct 04, 2010 7:56 pm

David Pinnegar wrote:Without having auditioned this particular speaker, the specification is capable of being interpreted to tell us that this type of speaker however beautifully and cannily engineered simply cannot reproduce happily a Wurlitzer Trumpet stop and I'd predict that a Diapason might sound a tad plastic.


David,

If you have never auditioned this speaker how can you possibly pass judgment upon it? I have been involved with sample design, mostly of WurliTzers for fifteen years and have prepared many thousands of samples, each of which required meticulous critical listening. The HR824 has been my primary reference system, although I do also have a number of much more expensive speakers such as the B&W DM802. I can state categorically that the Mackie HR824 can and does happily reproduce a WurliTzer Trumpet and Diapason.

Joe
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Re: Beyond Stereo to multiple Speakers

Postby David Pinnegar » Mon Oct 04, 2010 8:24 pm

toplayer2 wrote:
David Pinnegar wrote:Without having auditioned this particular speaker, the specification is capable of being interpreted to tell us that this type of speaker however beautifully and cannily engineered simply cannot reproduce happily a Wurlitzer Trumpet stop and I'd predict that a Diapason might sound a tad plastic.

If you have never auditioned this speaker how can you possibly pass judgment upon it? I have been involved with sample design, mostly of WurliTzers for fifteen years and have prepared many thousands of samples, each of which required meticulous critical listening. The HR824 has been my primary reference system, although I do also have a number of much more expensive speakers such as the B&W DM802. I can state categorically that the Mackie HR824 can and does happily reproduce a WurliTzer Trumpet and Diapason.


Dear Joe

I can tell from the spec. Whatever the excellence of the pedigree of these speakers and the cleverness of the designers, and whatever the theories upon which such speakers as this genre are based, this genre does not overcome the limitations of physics to which I have referred and others. I have played with speakers with similar but more lenient characteristics: there's reproduce for the home and reproduce for performance. I would not choose this spec for performance.

No doubt for monitoring purposes of assessing recordings of samples they have been and are perfectly fine: they are made to be and have clearly proved themselves in use.

Best wishes

David P
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Re: Beyond Stereo to multiple Speakers

Postby wurlitzerwilly » Mon Oct 04, 2010 9:03 pm

David Pinnegar wrote:
I can tell from the spec.....................


Surely David your previous argument (below) rather negates your current one (above)?
David Pinnegar wrote:They look very fine. The figures and graphs are very impressive. But when one realises as pointed out that the distortion figure is that of the amplifier rather than the whole product, one starts to realise that all is not all that it seems and there might be a bit of blinding by science going on. They will have been measured with very expensive equipment measuring to great accuracy in a nice anechoic environment but our ears are the best measure of the criteria that are being measured.
Regards,

Alan.
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Re: Beyond Stereo to multiple Speakers

Postby David Pinnegar » Tue Oct 05, 2010 5:50 am

wurlitzerwilly wrote:
David Pinnegar wrote:I can tell from the spec.....................


Surely David your previous argument (below) rather negates your current one (above)?
David Pinnegar wrote: but our ears are the best measure of the criteria that are being measured.


Dear Alan

Having heard what I mean by speakers, you know how particular I am to achieve something that sounds real and blatantly, identifiably "there".

I will always audition a shortlist, but that type of spec is not a design that I'd put on a shortlist for anything other than recording monitoring or punchy rugged PA. The technical spec of this genre of speakers is not a horse that I'd put on this course.

Two way PA speakers are compromises. If they do well here it has to be at the expense of doing less well there. That results simply from the physics of sound. This is not a criticism of these speakers. The design engineers will have achieved the compromise that does the best it can for the greatest number of people but will not have designed it to purpose. Organ reproduction is a very specialised purpose, unlike almost any other and the spec indicates that the compromises arrived on do not have this purpose in mind.

I was at a brass band open air concert in the summer supported by some PA reinforcement. The speakers were either this brand or another that have seen mentioned on this list. They were three way and rather good. I was mildly impressed, and better than the two way also used in the rig. But as I walked around, I knew they were speakers, and the point at which the electronic piano did not sound wonderful with a worship group was perhaps an unfair test.

For a virtual reality in which speakers which are a window into the world beyond such high quality two way speakers are fine.

To go further one has to pretend to be the source of the sound rather than the observer of the sound. So one really has to think of the sound as if one is the organ pipe and collection of pipes and instrument all together and ask the question "How do I speak? How do I sing?" From the Wurly cabin inside the cruise ship, being the organ, we have to think "How do I get my sound out there through that port hole to the people on the Quay". As we're way above the water line the Captain of the ship has granted us permission to choose any porthole we like or even take a saw to the structure, as long as we keep the place windtight.

Hi-Fi is an obssessive quest often without simple or finite answers and clearly from people's passion for them these speakers are a good start. No doubt particularly fine at domestic volumes at which the assumptions on which they are buillt don't show up. There is simply a difference between reproducing or transmitting the sound and being the sound.

I don't want publicly to write further.

Best wishes

David P
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