Doc modding Marantz imperial 7

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Vinyl-ant
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Re: Doc modding Marantz imperial 7

Unread post by Vinyl-ant »

Laminate up a cube using squares of ply or whatever, cut square or round holes in the inside layers so that you have a chamber inside, them stick the cube on a lathe to round it off into a sphere with six flat faces.
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Re: Doc modding Marantz imperial 7

Unread post by karatestu »

Yeah, I had thought of something similar but I don't have a lathe :crying-yellow: :crying-yellow: :crying-yellow:
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Re: Doc modding Marantz imperial 7

Unread post by Fretless »

karatestu wrote: Fri Nov 13, 2020 7:04 pm Yeah, I had thought of something similar but I don't have a lathe :crying-yellow: :crying-yellow: :crying-yellow:
Got a tractor, Stu?

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Re: Doc modding Marantz imperial 7

Unread post by karatestu »

Genius :grin:

I got a tractor, yes. Need to get the back wheel off :grin:
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Re: Doc modding Marantz imperial 7

Unread post by Fretless »

Alternative method:

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Upstairs:
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Pro-Ject 1.2 + Grado Sig Jr + Cambridge Alva Duo
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Re: Doc modding Marantz imperial 7

Unread post by karatestu »

Brilliant :lol: The power take off is one of the most dangerous parts of a tractor though :shock:
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Re: Doc modding Marantz imperial 7

Unread post by karatestu »

How about something like this to attach the tweeter "dice" to ? :lol:

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The ultimate in flexibility :dance:
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Re: Doc modding Marantz imperial 7

Unread post by karatestu »

Quote of the week

"Slot loading effectively increases cone mass, which reduces fs and increases Qts. Sensitivity is also decreased. Air volume between cone and slot should be as small as possible, to avoid screwing up the frequency response at higher frequencies (say above 300 Hz for a 15" woofer)."

Reducing Fs always gets my attention :ugeek: . Not sure I want to increase qts in my case - bigger box required. Don't like the bit about sensitivity.

I am not even sure what I have at the moment is even classed as slot loading. Maybe more a very crap horn with very bad cone to horn interface . Who knows. More research required.
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Re: Doc modding Marantz imperial 7

Unread post by karatestu »

Found another omni type speaker - Diredt Acoustics Silent Speaker. The same designer as the 1970's EPI speakers I linked to up thread.

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Quote from Stereophile review "On Direct Acoustics’ website, Burhoe claims that stereo imaging is often pursued at the expense of timbral accuracy, and that he is more concerned with accurate reproduction of sound than of stereo imaging. I don’t have a problem with this because, at the end of the day, my evaluation of a component comes down to two metrics: does the component allow or cause me to have an emotional response to the music? and how am I going to feel when I pack these things up and ship them back?"

Seems to share the same view as me about the importance of (or lack of) stereo imaging :dance:

Stereophilereview here http://directacoustics.com/?page_id=301

The 6.5" mid bass is run full range with no electrical filter :dance: Second order high pass filter on the tweeter which is a 1' soft dome.
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Re: Doc modding Marantz imperial 7

Unread post by SteveTheShadow »

My own semi-omnis were inspired by Mr Burhoe. They had the same sloping top with 6.5in main driver. The tweeter of course was on the front, same as the cube.
I loved those speakers, but at the time I built them, I had some mental health problems, and the massive over-reaction I had to some criticism of them, both online and at a bake off, very nearly did for me. Very silly but I wasn’t myself at the time. Don’t ever want to go back into that particular black hole.

However that’s all water under the bridge. Been free of depression for two years now, am off the happy pills, and I still have a pair of 10in Faital drivers and a couple of SB acoustics tweeters. I have some unfinished business with omnis. They are however going nowhere near any bake off of any description. If I ever build them. Folk’ll just have to take my word how good they are.
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karatestu (Sat Nov 28, 2020 7:33 pm)
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