Doc modding Marantz imperial 7

[karatestu]

You're welcome Dave.

Some more interesting omnidirectional speakers (if that is the right term) are the Design acoustics D-12 from the 70's (of course).





A pentagonal dodecahedron (12 faces) with one down firing 10" bass, one up firing 5" mid (sounds familiar ), nine tweeters and the twelfth side accommodating a port.

I kind of like it but would have to get rid of the port and the xover .

[Alfi]

Some interesting and frustrating DIY woodwork required there Stu if you want a sealed unit!!

I like them - good luck to you!

Alfi

[karatestu]

Hey Alfi. I don't think i will attempt to build anything like that. I know the limits of my wood work ability and that is definitely past it

[Simon Hickie]

Stu, have you considered a fully active approach to your speakers? I realise that the active approach is anathema to many but I do see certain benefits and it is indeed the path I am currently following.

[karatestu]

Hey Simon,

I did think about it a long time ago (before i joined here). I think i am too far down the path of Mr Richard Dunn (and less is more) now to consider it.

I don't have an electrical xover just a 3.3uf cap on the tweeter. I did think about putting a high pass filter in the input stage of the tweeter amp's (just a resistor and capacitor)and removing the caps but then i thought about all the horror stories of tweeter's blowing with nothing between them and the amp.

[Daniel Quinn]

All crossovers are bad (passive or electronic) my current hypothesis is splitting the electrical signal in to frequenciey bands robs the musical signal of something fundamental.

[karatestu]

All crossovers are bad (passive or electronic) my current hypothesis is splitting the electrical signal in to frequenciey bands robs the musical signal of something fundamental.

I agree. Are you going to take it to the extreme then and use a full range driver like Stevetheshadow ?

[Daniel Quinn]

Don't know, I'm not convinced you get a better sound. After all, the doc used tweeters.

[karatestu]

Don't know, I'm not convinced you get a better sound. After all, the doc used tweeters.

I think you would need to suck it & see. Doc said he thought Steve's speakers were very good.

I think full rangers need to be point & squirt as the high frequency is directional. Saying that the Shahinian omni's seem to have sloped baffles that fire at the ceiling but not at 90 degrees to the floor (45 degrees ?).

[SteveTheShadow]

All crossovers are bad (passive or electronic) my current hypothesis is splitting the electrical signal in to frequenciey bands robs the musical signal of something fundamental.

I agree. Are you going to take it to the extreme then and use a full range driver like Stevetheshadow ?

Nothing wrong with full range drivers, provided you take steps to deal with the uptilted response trend. Full range drivers are anathema in the mainstream, and on most forums, with plenty of ill informed bollocks on show about why they cannot possibly work.

The first problem we have to deal with is the prejudice against grilles. Most FR drivers need grilles, and not just any old grille; they need properly engineered ones that provide progressive attenuation of upper mids outwards from the centre to the edge.
This is because FR drivers will shout in the upper midrange unless something is done to stop it, and it is this ‘un’ dealt with issue that gives them the screechy quality that rules them out for most people.

They can be doped but if you do that, then all the speed and transient attack goes. What also happens is that you then need a tweeter because you’ve killed the treble, so then, you might as well have saved your money and gone for a common or garden mid/woofer and a tweeter with crossover.

No....FR drivers IME need grilles to control their response. IME eq’ing them flat in software robs them of life.

Below is my own engineered grille solution for my Fane 12” full range drivers:


6th octave pink noise analysis, 10deg off-axis frequency response in-room:

6AACA857-C111-49B9-8A36-4600B11762EA.png (245.97 KiB) Viewed 2297 times

They sound great, without shout or screech, giving a fast, detailed sound, with good bass in their 100L sealed cabs.