Doc modding Marantz imperial 7

[karatestu]

A bit more on the first design with 50 mm dowel legs. Here is a plan view. So I think I will go with the top and bottom baffles showing the plywood ply's - I think it will act like a frame all the way around. The bottom baffle will have to be square obviously but I have two options with the top baffle.

I can either let the legs with quadrant missing come all the way up and be flush with the top of the baffle or I could use the baffle to cover the top of the legs. That will mean the top baffle is a funny shape - a square with little bubbles in each corner.

Like this. It's to scale



And this is the same top baffle with the 6.5" mid bass position shown. I can't get it central because I want to keep the tweeters behind it.



And here is that with the tweeter pod added. It overlaps the mid bass slightly but only about 1 cm which is the width of the mid bass' mounting flange.



This is the foam dice shaped thing I was trying to use. I have cut all the magnet cut out holes but not tried it yet.


I just love the shape. If it doesn't work then I will have to get some wooden ones made with lovely rounded corners.

[Ordinaryman]

Maybe then use some marine/ aircraft epoxy. Neither fail very often? and are a sensible price?

[TheMadMick]

Why not put the legs THROUGH the bottom baffle and rest on the top baffle. Should be easy to secure to both the top baffle and the sides? The only problem would be getting the holes accurately drilled in the bottom baffle. It might also be fractionally less stable.

[karatestu]

Hi Madmick,

Thanks for the suggestion. I had thought of that but as you say, the stability is compromised. With two kids of primary school age I have to take that into account. Initially I was going to make the stands heavy and lower the centre of gravity. Now I am going light then I think I need to keep the footprint as big as I can (within reason).

[Firebug1]

A bit more on the first design with 50 mm dowel legs. Here is a plan view. So I think I will go with the top and bottom baffles showing the plywood ply's - I think it will act like a frame all the way around. The bottom baffle will have to be square obviously but I have two options with the top baffle.

I can either let the legs with quadrant missing come all the way up and be flush with the top of the baffle or I could use the baffle to cover the top of the legs. That will mean the top baffle is a funny shape - a square with little bubbles in each corner.

Like this. It's to scale



And this is the same top baffle with the 6.5" mid bass position shown. I can't get it central because I want to keep the tweeters behind it.



And here is that with the tweeter pod added. It overlaps the mid bass slightly but only about 1 cm which is the width of the mid bass' mounting flange.



This is the foam dice shaped thing I was trying to use. I have cut all the magnet cut out holes but not tried it yet.


I just love the shape. If it doesn't work then I will have to get some wooden ones made with lovely rounded corners.

I think that the "Mickey Mouse" top plate would look lovely.

[Firebug1]

Mickey Mouse, brrilliant Why didn't I see that.

[karatestu]

Some tweeter "pod" developments. I have put four tweeters in one of them so far.

Some blurry pics

[Ordinaryman]

I got the other tweeter pod done a while back and I have been playing albums since.

I am almost lost for words (you wish ). There seems to be a number of things slowly coming together lately which have really propelled the experience I am having whilst listening to these speakers. I hope it's not just me listening more attentively Sometimes when you tweak something that you think will only affect one frequency band you end up homing in on that band.

I did at first and paid more attention to the high frequency but the music just took over and it is evident that what I have just changed has altered things top to bottom. Listening to Fleetwood Mac Rumours I became aware of something in Dreams. I can clearly hear now how tight Mick Fleetwood is clamping his hi hats together throughout the song. He doesn't keep the pressure down with his foot the same. It is constantly changing very slightly which gives an up and down kind of feeling and it is very cleverly done. I can also tell now that he is altering where on the hat he is making contact with the tip of the stick. Now , this wasn't entirely obvious tome before but it is startlingly clear now

These little revelations happened throughout Rumours and the other two albums I have played (The Police Synchronicity & Kate Bush The Whole Story). It comes across as extra detail and I suppose that's what it is but at the same time there is an increased level of composure, the band's choice of instruments and sounds makes so much more sense and their level of genius is elevated in my mind.

[Ordinaryman]

Would absolutely Love to hear them . What a journey, could you not step back awhile and just enjoy? Aesthetics are imo important but not more so than the sound. enjoy ,relax and just make sure if you can, you emulate what you have built now, as close as possible when you produce the finished version, if that ever happens . I'm sure you'll find something to "tweak" no matter what

[karatestu]

So what accounts for this improvement ? I am putting it down as an improvement not a difference.

The little wooden cubes I had the four teeters in before were put together in a hurry out of rough scraps of chipboard. None of the edges were rounded over and they were just plonked on top of a piece of cardboard with the same footprint.

So I think the rounded over shape of the dice shaped pod is having an effect with regards to less diffraction. But the material the tweeter pod is made of has changed as well so I am clutching at straws but from what I know about speakers they seem to be the obvious reasons. The pod is in exactly the same place that it was before.

So is the foam having a good effect ? Don't know. All I know is the improvement it has made as a whole. It could be the foam transferring less vibration to the tweeters. Also the up firing mid bass might not be reflecting off it as much and some of the bass can travel through the foam of the tweeter pod. I was worried before doing this that the foam dice would not be rigid enough and that the tweeters would be able to move. I don't think that this is happening, there isn't any smearing. It has in fact tightened things up

I had cut the hole for the tweeters a while ago with a hole saw which was slightly too small in diameter. When I pushed the tweeters in they stayed where they were because the foam was gripping around them. I didn't even have to cut a notch out for the lead out terminals

They still haven't moved but I am thinking of some way of having hollow wooden connecting rods between the two opposing tweeters and screwing into them at both sides. The top and front tweeters would need either connecting rods to screw in to that connect to wooden discs on the opposing side or some way of attaching them to the rods that connect the two side firing tweeters.

I am very happy with the way things have worked out so far with these foam dice shaped tweeter pods. I kind of like the contrast between the black of the tweeter and the white of the dice. I will probably end up making it all black though as to not draw too much attention to it. then need to think of some way to stop little fingers pushing the fabric domes in