Doc modding Marantz imperial 7

[karatestu]

More fffing about with speakers here.

I wanted to hear what the 12" and tweeters would sound like on their own with no 5" mid. 12" down firing and tweeters front firing with 12R padding resistors back in.

It does not sound as bad as i thought it would, in fact it sounds ok There is not a big hole in the middle like i thought there might be. Also i am finding out just how much bass these isobaric 12 inchers are putting out and how much mid range both the tweeter and bass drivers are putting out.

Obviously the bass drivers are delivering frequencies right up to their natural roll off all be it attenuated by the doping. The tweeters with their simple first order electrical high pass filter are passing a fair bit of mid range due to the shallow roll off slope that a first order filter brings.

I am quite enjoying this, in some ways it is better than with the 5" in the mix More to come later when i have listened to more music.

[Latteman]

Have u messed with passive radiators yet

[karatestu]

Have u messed with passive radiators yet

No. Did think about it once but then read about RD's dislike of them so didn't consider them again.

[karatestu]

Put the 5" mids back in. I now realise how much weight in the mid band was missing without them. It was a valuable thing to do however. 5" will be staying.

Next up is trying them all in point & squirt as i never tried it with all three drivers.

[Latteman]

Im point n squirt at the moment as the up firing 12” wasn’t working with my room but now I think it may have been as it was wired in serial - current configuration is parallel and bass is better defined and punchy

[karatestu]

Well here we go round in circles again

Decided to go back to front firing bass drivers again. Down firing is out of favour with me again. Going back to front firing and the lower frequencies are definitely clearer. I promise i am not going back to down firing again

Have my little cuboids on their sides with 5" drivers both firing in and tweeters front firing. I have set up the big bass cubes so they are not toed in at all. That should keep any beaming out of line of the listening position. With them being at floor level they would be firing at my shins anyway. Also the little cabs are not toed in either so i can see the 5" drivers a little.

Interesting experiment, i am not sure i ever did this ??? I am wondering if i prefer to be seated off axis from the tweeter.

[karatestu]

Im point n squirt at the moment as the up firing 12” wasn’t working with my room but now I think it may have been as it was wired in serial - current configuration is parallel and bass is better defined and punchy

So you had yours with bass and mid/bass wired in series and you now prefer it in parallel ? Doc preferred series wiring and DQ also does. I preferred parallel when i tried wiring the two isobaric 12 inchers in parallel but that is not quite the same as with bass and mid.

How are you liking the P&S ?

[karatestu]

I have been reading about BMR drivers (balanced mode radiator). They have been around a while are sort of a cross between a pistonic cone speaker and panel. They are completely flat like a panel but still use the voice coil and magnet arrangement of a conventional cone speaker.

They are supposed to have a very wide dispersion angle so the frequency response is the same off axis as it is on axis. That got me thinking The 5" mid bass that Doc doped for me are filled with dope right up to the surrounds so almost flat.

So have i got something like a BMR with very wide dispersion ? Answers on the back of a postcard please.

[karatestu]

5" drivers back up firing on top of bass cube with 12" firing forwards.

It has to be said this is the best combination in my situation and that i have tried so far. Can't do up firing 12" and 5" without having the small cuboid at the side of the big bass cube. To do point & squirt i need to remove the 5" mid from it's cab and swap it to the other hole below the the tweeter which has an aluminum blanking plate in it.

[montechristo358]

Stu box positioning challenges aside, are you rating front firing 12" as better than up firing