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Re: Doc modding Marantz imperial 7
Posted: Fri Jan 03, 2020 8:04 pm
by karatestu
Latteman wrote: ↑Fri Jan 03, 2020 7:48 pm
It never ends as then the listening and tinkering starts
I know you are right but i want a finished pair of speakers which look and sound good, hopefully before the end of the decade
I have problems with diy deadlines because there is always something else to try and it niggles away at me
Re: Doc modding Marantz imperial 7
Posted: Sun Jan 05, 2020 2:01 pm
by karatestu
Found this which has a few similarities to the design i am playing with. It is a JBL Aquarius 4, which i had never heard of until now. This has a port
and does not have a driver firing upwards in the top enclosure. It is slot loaded where the down firing and up firing drivers meet.
I am not sure my design would be referred to as slot loaded as mine will be open on all four sides rather than just one side. EDIT - the JBL is open on all sides as well
Also i am not sure that there is a driver firing down wards from the top enclosure
My bad. It is described as a loading plug with stuffed trap ????? Looks like a diffuser.
http://www.audioheritage.org/html/pr ... s.htm
Re: Doc modding Marantz imperial 7
Posted: Tue Jan 07, 2020 5:13 pm
by karatestu
Re: Doc modding Marantz imperial 7
Posted: Tue Jan 07, 2020 5:21 pm
by karatestu
I notice the Linn Isobarik had the mid and tweeter mounted the opposite way around to mine. Linn had the tweeter at the back of the top panel where as i have it at the front.
Not sure what difference it will make ???? I could rotate the top panel and try it both ways (if i can be arsed).
Re: Doc modding Marantz imperial 7
Posted: Tue Jan 07, 2020 6:34 pm
by karatestu
Found a different sealant to use when mounting drivers etc. It's gutter sealant in a tube to be applied by a gun. It doesn't go completely hard and it's black
I don't need it to be an adhesive as i use screws so is just the job. With all the removing of drivers and panels that i do when experimenting it should make things easier. Decorator's caulk is ok but it does adhere things together ( not as bad as silicone sealant though).
Re: Doc modding Marantz imperial 7
Posted: Wed Jan 08, 2020 12:07 am
by Latteman
I use black silicon sealant for fixing drivers, have used gasket sealant too but that is much more permanent.
The ‘roof’ of my speaker is a very heavy ceramic and granite tile mix that couples to the rest of the speaker with draft excluder so easy access if needed
Re: Doc modding Marantz imperial 7
Posted: Wed Jan 08, 2020 5:37 pm
by karatestu
Decided to mask off the surround of the new 5" drivers. I remember Doc saying that it did not matter if dope went on the surround but i am paranoid after reading on classic speaker pages that it has an effect on resonant frequency.
Look like little flowers
Idecided to give them a couple of coats of plastidip to start with and then have a listen. Some dust caps have melted after being doped with bison kit so i thought it would be wise to put a layer of plastidip between them. Paranoid ? Maybe.
After the plastidip was applied
Going to have a quick listen tomorrow and then apply some bison kit
Re: Doc modding Marantz imperial 7
Posted: Wed Jan 08, 2020 5:46 pm
by karatestu
I needed to get the 5" drivers and tweeters out of my little semi omni cuboids in preparation for mounting them in the new enclosures. When i mounted them originally i used silicone sealant. The buggers are very hard to get out in one piece. Way back i had to remove one of the 5 inchers to sort a buzz that was caused by one of the lead out wires touching the cone. I remember i had to jack it out with a bottle jack.
So, i went and got the jack
There was a disconcerting noise as i jacked it up which was the sealant stretching before letting go. No drivers were damaged in this procedure. I learned a while back not to use silicone for mounting drivers again
I couldn't jack the tweeters out so found a length of 3x3 wood (longer than the cabinet depth) and arranged it with one end on the concrete floor and the other on the back off the tweeter magnet. Pushed down on the little cab and hey presto the tweeter was free. Turned out a lot easier than getting the 5 inchers out.
Stay tuned for the next episode
Re: Doc modding Marantz imperial 7
Posted: Wed Jan 08, 2020 6:17 pm
by karatestu
Needed some tunes whilst my little cabs are out of operation. So taped this crappy full ranger in that i liberated from a knackered portable cd player.
Sounds good enough for the time being whilst i get the new enclosure done. It has highlighted one thing though. Point & squirt sucks
The volume is quite a bit louder now so this little full ranger must be a bit more efficient than the doped 5 inchers. When i get the new enclosure finished with two 5 inchers in it i will gain some efficiency there
I just plugged the back of the old cuboid with some foam and put a bit on the top to cover the old cut out for the 5 incher.
Don't it look glorious
Tomasz will love this one
It's just to see me through til the other cab is done. I am enjoying the distortion . It's not half bad actually.
Re: Doc modding Marantz imperial 7
Posted: Thu Jan 09, 2020 11:29 am
by karatestu