Nearfield ribbon?

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
I am very interested in using a ribbon in a near field setup. Everyone I have talked too tells me not to do this. My question is why can you not implement this correctly. I am not a novice by any means but I am fresh to ribbon technology. It seems that everyone has an impression that it has to play to 20hz and has to play loud on another forum I visit. This is OK for car but in a home easy listening and moderate volume should work OK.

For example if the midbass I use has a 1-watt SPL of 90 and the ribbon has a 1-watt of 96, could an LPAD of – 9 db be enough to tame the ribbon?

The availability of ribbon headphones makes me question the fact that ribbons are not good for near field.

Drivers I will use are
Usher 8945A in each cabinet bass reflex
I will design the crossover around the drivers and test to tweak for better sound.

I would like to use one of the three. And I am leaning more on the Fountek NeoCD3.oms
.
Fountek NeoCD3.oms. I like the look of the driver and it appears to fit my needs.
http://www.madisound.com/catalog/pro...3d2d03384d1897

HIVI RT2-PRO I like this driver and I think it would fit my build. It looks great. The price may put this out of my budget. But I may swing the extra cost if needed.
http://www.partsexpress.com/pe/showd...number=297-404

HIVI RT8-II I love the way this driver looks but I think it may be a little much for my needs
http://www.partsexpress.com/pe/showd...number=297-413
 
The availability of ribbon headphones makes me question the fact that ribbons are not good for near field.

The fact that there has been numerous successful speaker designs through the years that utilized ribbons, in one form or another, in 2 and 3 way speakers makes me question this claim. Infinity with the EMIT, and ESS with the HEIL (ya I know, not really a ribbon) to name just 2. I have heard countless commercial, as well as diy speakers that have used ribbons in smallish listening rooms..they all sounded good to varying degrees. I even set up a pair of Apogee hybrids in a room 8' x 10' at my bosses request just to show customers it could be done.

For example if the midbass I use has a 1-watt SPL of 90 and the ribbon has a 1-watt of 96, could an LPAD of – 9 db be enough to tame the ribbon?

Yep.

I would be curious to know what you were told that would preclude their use in a home environment.

Casey
 
A well known raw driver store "not parts express" told me that it was not possible to create a good 2 way with a ribbon and 7. I will not name the company because I do not want to flame them. They told me that the ribbons are to directional. And Nearfield will not yield a good image.

Here is my theory. I purchased the HiVi RT8-II because it is a mid/tweeter. Recomended cross point is 1700 on the HIVI. I figured I could do a 18 DB 1800 slope on the tweeter and 6 db 1800 slope on the mid and have a useable speaker with no more than 30 watts per side. I will Lpad around -1 / -3 of the actual Mid sensitivity. This will change with testing and time I am sure.

I went ahead and purchased the Fountek Neo 3's for a 3 way tower. I may try them out on the 2 way also. The slope will be closer to 2500 or higher with these drivers.

The 3 way will use the Fountek Neo 3, Peerless 4 inch mid's "Have nice flat use out to 5000", and an undetermined sub. This project will be a fiew months out.
 
All drivers are directional at some frequency, but you probably know that... for ribbons it depends on the length of the ribbon. The longer, the more directional at HF. In nearfield, reflections are less important, you hear more of the direct wave, so you may hear funky stuff while moving your head. (that doesn't happen with headphones since they move with your head). I listened to some ribbons and the sound definitely changes when you get up from the seat. But yeah, it sounded good !

> I will Lpad around -1 / -3 of the actual Mid sensitivity.

Come on, grab a few LM3886 and make those babies active ;)
The cost of an active XO channel (opamps + caps + LM3886) compares favourably to a few good quality passive XO parts (like big air core coils, big caps, etc). For a 2 way it's OK, but for a 3 way the woofer XO parts start to get a bit too massive...

> Recomended cross point is 1700 on the HIVI

Try a distortion analysis first... I'm totally hand-waving, but "know your drivers" is the word ; some ribbons distort a lot at LF.
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.