You're correct, merlinx76, and I apologize. I read the Maximum Excursion (11 mm) instead of Xmax (6.5 mm). Still your statement that a single 18W/8747 is nearly as capable as a pair of 18W/8531s is more than just a bit of an overstatement.
Paul
Paul
If you model the 2 systems in a sealed box with the same QTC, the 18W has an Fsc nearly 10hz lower which means it reaches Xmax quite a bit sooner. If I model them to Xmax, I get exactly the same db output from a single 18wu vs 2x18w except of course 10hz less low end extension.
I don't know how well that translates to real world. How does a little woofer sound playing 800hz while moving around by 9mm even if the motor is very linear? I assume there would be some downsides to the loss in cone area.
Actually if you realise what is happening in a real vented woofer system, you might realise this, if properly done, the excursion peaks at a higher bass frequency. The work of low bass frequency is actually done by the port. Those woofers that actually see goes nuts are those that that has bass far below the port tuning frequency. That is when the woofer goes berserk, worst still it has no output. Example rumble from record player. If you can filter out the bass 5-10 Hz below your port tuning frequency, I doubt you will run out of steam...
Oon
Oon
Sorry, I think I kissed out a point. I meant at the preamp line level, a bit tough to do it at the speaker level.
Are you aware of the SPL reached when a 7" woofer does 9mm one way at 800Hz? 😀
On low-cut BR systems: Applying a highpass on a vented system is pretty normal in PA. And for us audio fans it also has it's use, either as low end extension or as safety measure for smaller systems playing on the edge. Can be done with dsp easily and just as easily with an active op amp circuit. No news though here. The latter goes back almost 4 decades. FWIM search for D.B. Keele.
oon_the_kid - I was talking about a sealed box which is how I intend to use them.
markbakk - The speaker is not only playing an 800hz tone. It is moving around by as much as 9mm (down to 60hz) while also playing up to 800hz.
markbakk - The speaker is not only playing an 800hz tone. It is moving around by as much as 9mm (down to 60hz) while also playing up to 800hz.
Hallo Line Sourece
As I can see, you are very familiar with SB drivers. I am loking to build some 3 way floorstanders (TW29R+MW16P+ 8",10", 12") Do you have some developed projects/ sugestions?
Bestg Regards
Hi EmuMannen, I intereseted this Project Speakers, which final Crossover on 3 picture scheme XO ?
I ended up using a fully passive XO (the active and semi-active versions is slightly better but fully passive is more flexible for me amp rolling my vintage amps). I recommend extending bass down to 30 Hz with a LT or similar filter (even with a fully passive XO). Attached is the schema for the passive XO:
That is correct, it is a sealed enclosure compared to Troels ported 3WC. Easier to get somewhat right and easy to extend bass with a LT. I am still satisfied with my pair and use them on a daily basis (right now paired with a Quad 34 + 405-2).
in : The 3-Way Retro Part 5 link, I found of DSP tools, what for that? actually its pasive speakers or active speakers? Have you picture rear side of speakers?
I have built them as active, semi-active and passive (it is all described in different blog posts). I ended up with the fully passive version but you can build them semi-active or fully active if you want. They look the same from the back in any configuration since the active versions was driven from external amps (including any active XO).
If I want to build
If I want to built a full passive version of the speaker, is this xo scheme suitable/ideal?
Can the new version of the sb acoustic speaker with the norex code be used on the xo, or does the design have to be adjusted again
The XO is good and doesn’t require as many components as a higher order, but is it ideal? That is a matter of definition. I have no experience with the norex version so I can not say.
@EmuMannen
What is the advantage of your crossover design vs a more classic design (with appropriate component value changes) like this?
What is the advantage of your crossover design vs a more classic design (with appropriate component value changes) like this?
Attachments
I am not sure it does and “a more classic” is a matter of definition. I started out with the active and semi-active version of the speaker. The first XO board had to take care of the mid and high element. I therefor splitter the incoming signal at the lowest XO point with an active filter. I then added a separate board for the low element, just replaced the active filter with a passive block, when I made the fully passive version. I kept these branches and XO blocks separate to be able to switch between semi-active and fully passive and I wanted to modify the already made boards as little as possible. I hope it explains why the schematics ended up the way they did.
Phase integration of mid and tweeter can turn out better with the tweeter behind the mid cap.