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 Post subject: HMV 102 acoustics test
PostPosted: Tue Jan 14, 2020 7:48 pm 
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Victor Jr
Joined: Sat Dec 21, 2019 11:16 pm
Posts: 12
Location: Michigan
I bought an HMV 102 on eBay in September. I was so impressed with the how clear and loud it was, it started me thinking about when I first got my Credenza over 25 years ago. My job then was in the office of a factory that had a long center aisle, probably ⅛ of a mile. I always wanted to take my Credenza there on the weekend when nobody else was around, and have an accomplice spin it up at one end of the aisle, with me standing at the other end to hear what it did with those acoustics. Alas, it never happened.

These days, a friend of mine works at the Michigan Theater in Ann Arbor, Michigan. He had to work Christmas day, so I asked if I could go with him early, and bring the HMV 102 to put on the front of the stage to listen to it. Here is a pretty bad video of that, but it gives a fairly accurate impression of what it sounded like.

(Double-click the video above or click this link to go to the video on YouTube.)



Has anyone else here been curious enough to take one of their machines somewhere else to hear what it would sound like?

Bill


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 Post subject: Re: HMV 102 acoustics test
PostPosted: Tue Jan 14, 2020 10:24 pm 
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Victor III
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floating down stream ...
Joined: Tue Feb 20, 2018 12:52 pm
Posts: 598
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That is a very good video and a very good question.

It made me think - here I am, with a few portables, and what do I do ? They go no-where ! Just played in the house.

I think I will do as you did and play them in different locations as they were intended. Nothing as grand as where you were though.
Sun turnin' 'round with graceful motion
We're setting off with soft explosion


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 Post subject: Re: HMV 102 acoustics test
PostPosted: Wed Jan 15, 2020 4:48 am 
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Victor III
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F. Depero, "Grammofono", 1923.
Joined: Thu Feb 24, 2011 4:19 am
Posts: 930
Location: Italy
The videoclip sounds exceptionally well for having been recorded "live" while moving around, and possibly with a smartphone.

In November I have been asked to perform once more the commemoration Il Suono Della Grande Guerra for the 101st anniversary of WWI victory. This time the location would not be a hall as in previous events, but a municipal theatre (again, not even by far as large and as elegant as the one in your clip, but still a theatre). At first I worried that the sound would be too faint to be clearly heard from the rear rows, and I agreed with the organisation that they would provide microphones and an amplified loudspeaker cabinet. However, during an afternoon reharsal it became evident that the gramophones - even the Decca "Trench" - could do it by their own. 8-) Quite impressively, some spectators later told me that the music could be pleasantly listened in the entrance hall just as well, and that it was audible even outside the theatre.


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 Post subject: Re: HMV 102 acoustics test
PostPosted: Wed Jan 15, 2020 4:56 am 
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Victor III
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F. Depero, "Grammofono", 1923.
Joined: Thu Feb 24, 2011 4:19 am
Posts: 930
Location: Italy
The videoclip sounds exceptionally well for having been recorded "live" while moving around, and possibly with a smartphone. I am trying to do some recordings myself lately, and the more I go ahead the more I realise how hard it is to convey the quality of sound that you hear "live" with your ears.

In November I have been asked to perform once more the commemoration Il Suono Della Grande Guerra for the 101st anniversary of WWI victory. This time the location was not going to be a hall as in previous events, but a municipal theatre (again, not even by far as large and as elegant as the one in your clip, but still a theatre capable of a hundred spectators). At first I worried that the sound would be too faint to be clearly heard from the rear rows, and I agreed with the organisation that they would provide microphones and an amplified loudspeaker cabinet. However, during an afternoon reharsal it became evident that the gramophones - even the Decca "Trench" - could do it by their own. 8-) Quite impressively, some spectators later told me that the music could be pleasantly listened in the entrance hall just as well, and that it was audible even outside the theatre.


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IMG_20191104_1924485.jpg [ 5.12 MiB | Viewed 182 times ]
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IMG_20191104_1919074.jpg [ 3.67 MiB | Viewed 182 times ]
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DSC_9806.JPG [ 2.86 MiB | Viewed 182 times ]
DSC_9826.JPG
DSC_9826.JPG [ 2.87 MiB | Viewed 182 times ]


Last edited by Marco Gilardetti on Wed Jan 15, 2020 5:27 am, edited 1 time in total.
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 Post subject: Re: HMV 102 acoustics test
PostPosted: Wed Jan 15, 2020 5:10 am 
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Victor III
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Keep'em well oiled
Joined: Mon Dec 18, 2017 2:51 am
Posts: 687
Location: Madrid, Spain
These machines, even the smaller 101, sound marvelous. There is something anybody can do at home: take a wide room with an empty corner, place the portable on the floor, at the corner, facing towards the center of the room, following the ideal'axis' of the corner, so the floor and the two adjacent walls act as an extension of the horn. Play a record and place yourself along this ideal axis, far from the gramophone, and listen. The sound is marvelous.
Any small tabletop can be located the same way, and will give the same amplification effect.
What's more: you can do this with a small portable radio receiver, even a cell phone. Start the sound, place the sound source at the corner in this way, and notice how the corner amplifies the sound. For a better contrast, take the radio on your hand, with a medium agreeable volume, not the distorted maximum, listen to it, then placed it on the floor at the corner, and go away to the center of the room... and listen how it amplifies.
Another nice experiment: play music on your cell phone, medium volume. Then place the cell phone into a medium sized salad bowl, go away and listen!
Any tabletop or portable gramophone sounds better just placed on the floor.
Inigo


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 Post subject: Re: HMV 102 acoustics test
PostPosted: Wed Jan 15, 2020 5:45 am 
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Victor III
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F. Depero, "Grammofono", 1923.
Joined: Thu Feb 24, 2011 4:19 am
Posts: 930
Location: Italy
That happens because by putting the sound source in a corner, the steradians over which the sound is deployed are reduced compared to when the source is placed at a dihedral, on the floor, or in free field. Not only there is an overall gain of +9 dB (well.. at least theoretically) by putting a source in a corner, but in the case of a horn-loaded source it can also be demonstrated that the lower frequency response is broadened.

I understand that "amplification" is used by most as a colloquial term; however, since it is wrong and there is not by any means any amplification, we should try to avoid it and replace with the concept of impedance adaptment. ;)


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 Post subject: Re: HMV 102 acoustics test
PostPosted: Wed Jan 15, 2020 7:03 am 
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Victor III
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Keep'em well oiled
Joined: Mon Dec 18, 2017 2:51 am
Posts: 687
Location: Madrid, Spain
Marco, I agree. The simplification is fully intentional...
The basis of my corner horn project design sits on this principle. The reduction of solid angle diffusion in such a 90/90/90 degrees corner is an eighth the full spherical angle, so the horn cross section is divided by eight accordingly.
The effect on small sound sources installed in a floor or ceiling corner with two perpendicular walls also based on this principle, as you said.
Inigo


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 Post subject: Re: HMV 102 acoustics test
PostPosted: Wed Jan 15, 2020 10:35 am 
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VTLA
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I played Mendelssohn's Wedding March at my daughter's outdoor wedding on my VV-50. It could be heard with comfortable volume across the small park with about 60 people. Of course it helps that people tend to be quit during a ceremony. The same would be true for a theater or concert. The problems with volume they had back then was for dance events when many people are talking and there is a lot of noise otherwise.

Andreas


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 Post subject: Re: HMV 102 acoustics test
PostPosted: Wed Jan 15, 2020 11:45 am 
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Victor II
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Posts: 210
Location: Boyertown, PA
Nice job, the impact of the experience really comes through!
“The cup of tea on arrival at a country house is a thing which, as a rule, I particularly enjoy. I like the crackling logs, the shaded lights, the scent of buttered toast, the general atmosphere of leisured cosiness.”

P. G. Wodehouse


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 Post subject: Re: HMV 102 acoustics test
PostPosted: Fri Jan 17, 2020 1:17 pm 
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Victor Jr
Joined: Sat Dec 21, 2019 11:16 pm
Posts: 12
Location: Michigan
Thanks for the kind words and suggestions!

The Michigan Theater is 1,200 seats including the balcony.

It was my assumption that toward the back the main floor under the overhang of the balcony, there would be a dead spot for sound. I was surprised that though it was a little quieter because it was farther away, the sound didn't degrade, at least to my ear.

When I go back, I want to listen and get some video of how it sounds in the balcony. Based on what I heard on the main floor, it should be just as good.

Maybe at some point I'll be able to smuggle in my Credenza to hear how it sounds.

Bill


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