HiFi Subjectivist ¦ Audio Forum ¦ NVA User Group

Just a quick note about imaging and sound staging. If you value those aspects of music reproduction above all else then you would not like my speakers very much. Pin point imaging has been sacrificed in the quest for something else - but what is that something else ? Do i actually know what it is i am chasing ?

EVERY speaker is a compromise where certain characteristics are favoured over others. Some chase phase coherence, imaging, sound staging, directivity, omni directional, single point source, cross over less, flat frequency response, high sensitivity, low bass f3 blah blah blah recurring.

So lets take the starting point of this project. A 3 way 1970's ported speaker with 12 " woofer. Why did i chose the Marantz imperial 7 ? They were cheap and they had a 12 inch woooofer I wanted bass man and good bass at that. Turns out the marantz drivers were mostly shagged although they could have been repaired if i really wanted to (which i didn't). I did try doping the marantz 12 inchers with not much success, i just don't think they were suited.

The project quickly changed to a semi omni thing because i tried it and loved it straight away. So i always new there was going to be a degree of omni direction to it. I just didn't realise then how far it would go with tweeters firing in all directions. There is something in the way it interacts with the room which i prefer and adding more and more tweeters on different baffles has only enhanced this (even though the output from a tweeter seems trivial compared to that of a woofer).

What i was not expecting was the lowering of distortion as more and more drivers are added. Easy to do with tweeters as they are closed back and the box doesn't have to get any bigger. The clarity of the music is leagues ahead of just one mid bass and one tweeter. No, really. The trade off is in my opinion is less pin point imaging. Not content with that i had to add another 5" mid bass to see what effect that had. Much the same as with the tweeters but this one is down firing. I had oversized the enclosure anyway knowing that this was going to happen.

Initially i wired the extra 5" in series with the other which meant that the work was shared between them and detail and clarity increased hugely. The other day after completing my last two nva based monoblocs i decided to wire the two 5 inchers in parallel instead of series giving an approx 4 ohm load rather than 16 ohms. I new what was going to happen (no really). The volume of the speakers as a whole has increased a fair bit. Well of course this has changed the balance of them over the frequency ranges. With too big a cap on the tweeters the music was a bit hot around the crossover region. This parallel wiring and lowered load on the amp has changed this.

It is not perfect by any means but the gains in volume are more than welcome. The moan about doped semi omni designs being too insensitive can largely be ignored now. Adding more drivers has addressed it It just so happens that with them on different baffles the omni directional aspect is taken further also. I am aware i have lost some of the added detail and clarity because now the drivers are moving more (the extra volume). IGNORE THIS LAST SENTENCE IT'S BOLLOX. I HAVE MORE VOLUME SO DRIVERS ARE MOVING MORE. IF I BACKED THE VOLUME DOWN TO WHERE IT WAS BEFORE THEN THE DRIVERS WOULD AGAIN BE MOVING LESS. JUST GOES TO SHOW HOW DISTORTION CAN INCREASE WITH VOLUME. So i need to add more 5 inchers to share the work out again and bring that lost clarity back (i may even gain further improvements). I reckon another two 5" drivers will do the trick. They can be wired in series parallel for an overall load on the amp of approx. 8 ohms. See how well that balances things out.

A speaker with a mid bass and tweeter on all four vertical baffles. Do any manufactured ones exist ??

Yes, from the 1970's (it had to be the 70's ) the EPI tower speakers from America. This model is the 1000 and probably as tall as me (6ft.) Edit - it's actually 6.5 ft









They measured flat apparently and had a huge, spacious sound that had many fans (and detractors). These are the first speakers that i have come across that have a set of drivers on the four sides of the cabinet. Well really they should have stuck a set on the up firing enclosure panel as well So it can be done and made to sound good.

Phase problems with this type of design ? Not that i have detected (i am sure there is somebody who would say the concept is crap) although currently i only have tweeters firing up, forwards, backwards and to each side. I wonder what it would sound like with 5.25" mid bass on all four vertical sides Couldn't do an up firing 5" if the 12" isobaric pair are firing up.

How about this positioning of your speakers. The soundstage will be a walk through experience These are smaller models but have mid bass and tweeter on all four sides.

Wo, what about these. Big brother of my Marantz imperial 7, the Imperial 9's. Lots of drivers going on here but all on the same baffle.

The 8" mid bass drivers in the EPI 1000 tower speakers are run fully open. The only crossover component in them is a single 10 uf cap on the tweeters. Remind you of any other speakers ?

http://www.humanspeakers.com/e/epi1000.htm

Having reading a fair bit about these EPI speakers i decided to rearrange my speaker positioning a bit. Mine were flat to the wall with no toe in at all. Apparently the 1000 tower speakers sounded best with one of each cab's corners toed in and directly pointing at the listener (if that makes sense ).

There are some differences between those speakers and mine of course - i don't have mid bass on the four vertical panels, my tweeters are all different and two in each speaker are total junk). This surely will make a difference. I am listening to it now. Not sure what to think about it yet.

Have you considered concrete horns, Stu?

No way. I would need a small extension on my house (well two actually )

I assume the owners of all those speakers are single, or soon will be?

slinger wrote: ↑Mon Feb 17, 2020 4:15 pm I assume the owners of all those speakers are single, or soon will be?

Should start a new thread entitled "Speakers that will get you divorced" I could start that one off very nicely