Doc modding Marantz imperial 7

[Latteman]

Hmmm
https://www.ebay.co.uk/itm/Bang-Olufsen ... 890.l49286

[karatestu]

In the spirit of suck it n see I removed the tweeter faceplates earlier today. I was sat listening and thought this sounds smooth and quieter???- logged on and read the above post. Thanks Stu

Do you like it Peter ? Give it time.

I thought I would lose projection but there is better integration of mid/bass & tweeters- I don’t have to listen for details etc- it’s just there with greater quality/quantity. The sound stage is more open and invites you in- very engaging

Jolly good Peter I am glad it has done something you like. I can relate to what you are hearing.

You would probably find it sounds even better if you mount your tweeters in a little sphere about 12cm diameter. Make sure that the whole thing is as smooth as possible especially what is behind the faceplate you removed and where the tweeter body meets the cut out in the sphere.

The effects are far from subtle, I think you will agree. It's good to have someone else try it and confirm my findings. I feel like an idiot for not paying diffraction much attention but I guess I was busy sorting bigger issues. The Internet is full of people banging on about how important it is to do a rebate for drivers and roundover cabinet edges. Now I have experienced a taste of what paying attention to it can bring I am on a mission to wring every last drop of extra detail, imaging, soundstaging, smoothness and enjoyment I can.

I keep thinking about grilles (as you do ) and I wish I didn't have to put any on. I am trying to think of a way to do it with mesh or fabric which does not ruin the good work as regards diffraction.

Just be careful Perer that the disc with the dome and voice coil attached can not move about in the magnet gap. As (like me) you have removed the faceplate and screws that clamp it down it is free to move which might not be good. I stuck mine down but made sure it is easily removable.

I look at most enclosures now (especially square edged monkey coffins) and can't help but think they have missed a trick. Diffraction is my new obsession. Paying attention to it reaps big rewards ime and it is something we can do without affecting the core principles of the design .

[karatestu]

Hmmm
https://www.ebay.co.uk/itm/Bang-Olufsen ... 890.l49286

1970's B&O tweeter cubes They should have made it a sphere They did some interesting and controversial designs which bring ridicule from the armchair speaker experts sat looking at their graphs.

Bids are up to £86 and rising

[karatestu]

My son has a persistent cough and eight kids in his class are off school with a cough I am taking him to Selby for a test. All four of us will be isolating now at least until the result comes back. Hifi time

School absences due to covid are up a third in a week.

[karatestu]

The sound stage is more open and invites you in- very engaging.

That sounds like how I used to feel walking past the take away back from the pub to my wife's (then girlfriends) house in York. It had a big sign in the window saying "welcome".

[karatestu]

One more thing I have noticed after removing the faceplates and improving diffraction is that sibilants are less pronounced. Not that they were a problem before but they sound more natural now. Some Stevie Wonder recordings emphasise sibilants and they are more rounded now.

[karatestu]

Smooth from dome to edge of faceplate and nicely rounded over. This sort of thing could be done and blend in with the curve of the spherical enclosure. Like a donut cut in half.




Just don't know what will happen unless I tried it. How would dispersion be affected ?? I like how it is sounding now with no faceplate and all the dome visible from the side.

[CycleCoach]

Can't see the pic Stu.

[CycleCoach]

Can't see the pic Stu.

Very odd, I could see it in chrome but not bing. It was a copy image address from diyaudio. Imgur would not upload it for a while but I have managed to upload it there now and replace the address. You should be able to see it in my last post now.

[karatestu]

Gone off that idea as it is bound to affect the dispersion and act as a sort of waveguide. Probably ok if you were making a point and squirt controlled directivity speaker. That's not what I am doing here

I am trying to do it in a way that means I can do away with the face plate altogether. My B&W P4 tweeters screw in to a plastic housing. That would be ideal but probably beyond the realm of my ability and the acrylic spheres would be too thin and their shape doesn't help.

As the tweeters are in a housing of their own I don't need to make it air tight and there will be no internal pressure to move the tweeters. For those reasons I think I might be able to use 0.6mm wood veneer as a faceplate of sorts. Might look good and at that thickness won't be much of a problem with the edges and diffraction. It only needs to stick out 5mm all around the tweeter.

Other options are being considered as well I don't want to end up making something I can't get the tweeters out of without damaging something.