The purpose is to turn a closed box into a pseudo reflex 3th or 4th order HP, but without ports or ABRs and their associated issues. This example shown by Rese 66 is one of the most succesful applications of the series capacitor concept (Geschlossene Hoch Pass: GHP/ Closed High Pass in German). There has been a brief discussion about this concept in one of the other loudspeaker threads. Do not recall which one...
Right, the caps are very large, with 8 ohm woofers typically between 400 and 1000 µF. With 4 ohm woofers twice as big. We have done this quite often with electrolytic caps and never had any problems. The larger tolerances almost don't matter, because the influence is only very slight at this point.
If you were to use foil caps at this point, they would cost as much or even more than the woofer - that makes no sense.
With this method you not only push the bass, you can also reduce the volume compared to a closed box with a Qtc of 0.7. Because the cap works most effectively with a Qtc of around 1.
If you were to use foil caps at this point, they would cost as much or even more than the woofer - that makes no sense.
With this method you not only push the bass, you can also reduce the volume compared to a closed box with a Qtc of 0.7. Because the cap works most effectively with a Qtc of around 1.
Given that you are going active with DSP you can just EQ it to the desired response
I read the above about the product and it says it adds delay to lower frequencies but in reality the bass has plenty enough delay...and adding delay to mids and highs would align then with the lows....
Found my answer
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One of the last published papers by the late A.N. Thiele was dealing with the practical dimensioning of this topology:
AES Journal Forum >> Closed-Box Loudspeaker with a Series Capacitor
Regards
Charles
How to model the GHP?
Take a proper simulator, preferably with an Optimizer function such as e.g. Vituixcad or Lspcad ,SoundEasy, Calsod, Leap. Take the closed box function, use in-box impedance and Nearfield SPL measurement files and start with a 1000 uF capacitor as x/o. Take a realistic target curve and start the capacitor value optimization process.
In case you use XSim or the likes thereof, it is a strictly trial and error process.
Most likely you will not reach such a near ideal solution as Rese66.
Funny how these age-old tricks reappear every 10 years or so.
Take a proper simulator, preferably with an Optimizer function such as e.g. Vituixcad or Lspcad ,SoundEasy, Calsod, Leap. Take the closed box function, use in-box impedance and Nearfield SPL measurement files and start with a 1000 uF capacitor as x/o. Take a realistic target curve and start the capacitor value optimization process.
In case you use XSim or the likes thereof, it is a strictly trial and error process.
Most likely you will not reach such a near ideal solution as Rese66.
Funny how these age-old tricks reappear every 10 years or so.
Of course, this does not work optimally with every woofer. Most drivers that are also suitable for closed boxes can be tuned well with it.
In Germany the simulation programs AJHorn and Boxsim are quite common and provide very practical results. But it should also work with other programs.
This trick has been used in our group for years, see for example:
Italian Pony
Silent Runner
Little Yellow Cab
Big Yellow Taxi
The last one goes well with the theme here too.
In Germany the simulation programs AJHorn and Boxsim are quite common and provide very practical results. But it should also work with other programs.
This trick has been used in our group for years, see for example:
Italian Pony
Silent Runner
Little Yellow Cab
Big Yellow Taxi
The last one goes well with the theme here too.
So all of my jbl products that are considered to be 2" are actually 1- 7/8ths......while the Axi is a whole 2"..it kind of left me jaded to even try my other horns due to this technical aspect. Whats the deal with that?
I finally came across a paint scheme that impressed me....I 'm accomplished at texture rolling poly enhanced cement only to realize that no matter what...after the cement sets and gets painted....it tends to look like a rock (the goal) anyway....and flat and smooth looks pretty appeasing....guess I'll texture lightly...
(sorry for the bad pic quality, actually the same model in both pics, lighting is closer to reality in the second pic, not sure why they didn't transfer as high res...)
I finally came across a paint scheme that impressed me....I 'm accomplished at texture rolling poly enhanced cement only to realize that no matter what...after the cement sets and gets painted....it tends to look like a rock (the goal) anyway....and flat and smooth looks pretty appeasing....guess I'll texture lightly...
(sorry for the bad pic quality, actually the same model in both pics, lighting is closer to reality in the second pic, not sure why they didn't transfer as high res...)
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The JBL's are supposed to be 49mm, 1-15/16", you must have some counterfeit products
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It is my understanding that the original question was regarding 2-way with a full frequency response ?. I uses a 'Response' CW2190 4 inch driver, and a 25mm Tweeter (CT2007). The tweeter is driven via a 3.3uF capacitor only. The 4 inch driver is mounted in a ported enclosure with a volume of 9.5 litres. The port is 4.2mm cm diameter and 16cm long. The frequency response of the system is broad and even.
I guess you didn't read the title properly: It also includes high SPL and low distortion. While I guess your speaker sounds nice and undistorted things would surley change as soon as high SPL comes into play .....
Regards
Charles
Edit: I was a little slow with posting. My response is refering to Is it possible to cover the whole spectrum, high spl, low distortion with a 2-way?
Regards
Charles
Edit: I was a little slow with posting. My response is refering to Is it possible to cover the whole spectrum, high spl, low distortion with a 2-way?
I think the custom horns designed, is the end goal, I was super interested in fabricating it myself but I started to doubt...I knew it would “be a while” so I had to purchase something to fill in the void, as well as an example of fine craftsmanship. So after receiving my e-tractrix from Germany I am not shy to pay a wood worker lol. I’ve seen some promising 3D prints but I’m second guessing...cnc and wood seem to be more precise but I digress... these are my first horns ever, so before you attempt the end goal I figured I’d get my feet wet?
Docali and Don k helped me come to a point. Don k finished a particular horn that I chose from their selection....During that time I revamped and raised the crossover goals to accommodate a smaller horn with better dispersion up top, one that still falls within, too narrow for some... so the developed horn profile needs to be adjusted to a tuning some where around 300hz (my guess is 320hz)...my e-tractrix is suppose to be 350hz Tuning but I think that’s conservative...likely 320hz...or Autotechs tunings are generous and the 350hz horns in their sight is more like 370hz...anyway... there’s that.
Tuning note vs dispersion at top register vs nearfield goal
Having about 15 degrees plus/minus beam width at the top, is familiar territory for tuning around 350ish from what I see.
Ok here’s where it gets more complicated...Docali kept making advancements in design theory and design and produced several other horns since then and I’m like a kid in a candy store so I’m wanting to move forward with whatever the latest and greatest approach is... Docali got tied up, Don K finished the one horn but the scale needs to be adjusted and roll over reapplied...as well consideration of the newer profiles Docali generated looked promising so not to downplay them just because of the previous design
The place where I got the tractrix from does custom fabrication but conversation is needed between me Docali and Don K in particular before handing over horn models developed not by myself
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