Doc modding Marantz imperial 7

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Latteman
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Re: Doc modding Marantz imperial 7

Unread post by Latteman »

Front firing tweeters done- I like it- clear n calm springs to mind
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karatestu (Thu Feb 25, 2021 3:56 pm)
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karatestu
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Re: Doc modding Marantz imperial 7

Unread post by karatestu »

I think I will end up going with the 5" bipole rather than the 6.5" version. The 5 " version is so good now I can't drag myself away especially since removing cdp filters and putting the high pass tweeter filter at line level. Added to that the force cancellation of opposing mid bass stiffly joined mechanically results in vastly reduced cabinet vibrations.

Plus the bipole design gives baffle step correction for free as it were. Even so, I can get the 5" version right up to the wall. The bass is awesome, tight yet rich, full and fruity :dance: I had a play in winisd with the 5 inchers as regards added weight from dope. When 5g of weight is added the F3 is reduced by a lot and I mean shit loads (to about 45Hz). That is the weight of a 10 pence coin which when put in your hand feels like bugger all. I wouldn't be surprised is the dope added to my 5 inchers isn't far of that.

The 6.5" bipole just does not want to be put near a wall. The bass is awesome when more than 1 metre from the wall but quickly turns to shite any closer than that. For that reason I am going to shelve that version and go with the 5" version which is wonderful. It pains me to do this as the bit of extra sensitivity from the 6.5 inchers us welcome but hey ho, nothing to be ashamed of with a little un ;)

I considered using more expensive drivers (monacor sph-145hq) which have a very smooth roll off and probably would need just some plastidip. But they wouldn't go as low as the drivers I have now although would be more sensitive. They need a bigger box as well (vas is 9.4 litres compared to 5.8 litres).

Gonna stick with what I have.
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karatestu
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Re: Doc modding Marantz imperial 7

Unread post by karatestu »

Since I have decided to go with the 5" bipole version then I have been able to finalise the dimensions. The tables I am using to build my speakers in to have splayed legs of 5 degrees in all directions so most of the cuts are at angles .I am only really using the legs but keeping the dimensions and angles. Yes I want to make it hard for myself :lol: The four sides won't be perpendicular to the top or bottom baffles.

Image

The cross brace and the panels which are in there now are to be removed. As I don't need so much volume now I have decided to go with the 5" bipole design I can really go to town on the walls, I was going to do a sand filled design with two skins and the cavity filled with sand but it was a bit too complex.

I have instead decided to make the sides out of 50mm (2") thick concrete slabs cut to size. I have done one to try it out and it fits well. I need to decide which glue to use because these are going to be heavy especially if I decide to make the top and bottom baffles out of concrete slabs as well.

Image

I have not decided on the baffle material yet. I would use concrete but the driver cut outs are hard to do and I want to do at least 1" round overs on the baffle edges to help smooth diffraction. The mid bass are not going in the centre of the baffle and that will help spread the diffraction frequencies around a bit. To do a round over to concrete panels would have to be done with an angle grinder and diamond grinding disk and so might not turn out very accurate.

Anyway the sides are defo going to be concrete and I will try and veneer over the top. I might have to do the baffles in Baltic birch ply with some sheet steel lining. We will see.
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Re: Doc modding Marantz imperial 7

Unread post by karatestu »

Done bugger all with anything recently :( Much too much farming to do but if I don't get these crops in then there will be nothing to harvest come August.

I have done some listening though and I have cone to the conclusion that my diy system is perfect for me. I am scared to change anything in case I spoil the magic. Played Stevie wonder Hotter than July yesterday whilst having my lunch. Thus is an album that I have not played on the diy system .....ever. I had forgotten how much I like it. It sounded absolutely wonderful. I wish I could just finish the system as it is and just fix the cosmetics.
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CycleCoach (Fri Apr 23, 2021 9:16 am) • SteveTheShadow (Fri Apr 23, 2021 11:48 am) • Latteman (Fri Apr 23, 2021 2:12 pm)
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Re: Doc modding Marantz imperial 7

Unread post by karatestu »

No progress here, too busy with work :(

Somebody has copied my design though (sort of) :roll:

Image

https://syngspace.com/

Force cancelling up and down firing mid bass and three tweeters but using waveguides. I like how the support pole goes through the down firing drivers pole piece (where the dust cap is). Pretty innovative part of the design. I also like the "roundness" of it.

It uses some new devilry which they call triphonic beam forming to adjust the spatial qualities of the sound field.

They are interesting however I won't be buying one. The use of any music killing new devilry rules it out for me.
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CycleCoach (Sat May 15, 2021 10:49 am)
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Re: Doc modding Marantz imperial 7

Unread post by CycleCoach »

I wonder what "triphonic beam forming" is. I suspect it's a marketing way of saying that there are "three holes for the sound to come out! "
I think I might be in the HiFi trade.
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Re: Doc modding Marantz imperial 7

Unread post by karatestu »

CycleCoach wrote: Sat May 15, 2021 10:49 am I wonder what "triphonic beam forming" is. I suspect it's a marketing way of saying that there are "three holes for the sound to come out! "
Haven't a clue :oops: . There will be some marketing bollox in there somewhere :roll: There are five holes - two for the up and down firing MB and three tweeters with waveguides. Must be something to do with the waveguides and some clever digital wizardry.

They have the tweeters forward of the up and down firing mid bass like Cubes, Allison and I used to have. The tweeters need to go behind the mid bass as it sounds so much better (honestly) which Latteman has also tried and concurs with my view. The only way around it is some sort of delay and that adds more components which in my experience is bad for the music.
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Latteman (Sun May 16, 2021 4:51 pm)
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Re: Doc modding Marantz imperial 7

Unread post by antonio66 »

Strangely enough, I was reading up on and listening to this brand on YT yesterday, their top of the range speaker is over £300k but all use the same DDD driver. I've always liked omni-directional speakers, so I pretty sure I would like these https://www.german-physiks.com/german-p ... udspeakers
Here's a dem of their cheapest speaker, still very much worth a listen
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karatestu (Sun May 16, 2021 9:20 am)

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Re: Doc modding Marantz imperial 7

Unread post by karatestu »

£300K :shock: :shock: :shock: I hope you do the lottery Dave, with taste like that :grin: I hope you realise they still won't be as good as a pair of Tannoy 'beamers or Dutch & Dutch cardioid bollox with bells on :grin:
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Re: Doc modding Marantz imperial 7

Unread post by antonio66 »

I have a feeling that the most expensive speaker is made more for concert halls and such, probably not for home use. They still make other models though, which cost more than you and I would pay Stu :grin:

Nice photo here, $112,000, which I would estimate would cost between £70-80k https://www.monoandstereo.com/2020/10/g ... peror.html
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karatestu (Fri May 21, 2021 9:13 am)

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