If you're trying to mate a HF horn with a 15" driver, you also need to take into consideration the z-offset (the difference between the acoustic centers for the drivers, relative to the listener's position) and also the directivity of the 15" driver and the horn at the chosen x-over point. And of course the type of horn you're using. A CD horn like the APT150 WILL require some sort of bypass cap or other EQ to address the HF rolloff, but can otherwise sound fine. For my Blastorama builds, I used them coupled to Pyle Pro PDS222 drivers (if you want to see inconsistent drivers, try those - I had to buy four and choose the two that matched the closest, and still they're not as close a match as the two APTs I purchased).
I swear the more I get into this hobby the less I know. Bypass caps... Did some reading. The theory (and many do not subscribe to) is that a small high quality cap placed in series of a larger less quality cap with reduce ESR and allow higher frequency content to pass faster? Might be something to fool with for a few bucks. I suppose it might even help the old EV's. I guess ROT is 10% of existing cap? Or am I off entirely?
Also open for other driver ideas.
Thanks for playing along!
Also open for other driver ideas.
Thanks for playing along!
That's a different type of "bypass cap"
With respect to CD horns, a "bypass cap" is something else. Look into "RC contour filters" for more details. Basically it contours the signal fed to the horn to compensate for the drooping response at higher frequencies.
Zwiller,
Parallel "bypass caps" will not correct the 4-5 dB VHF drop the APT150 constant directivity horn exhibits.
By "bypass cap" I was referring to using a smaller value capacitor that allows the VHF to bypass the attenuation resistors normally used to pad down the tweeter, effectively "boosting" the VHF range. If you are not attenuating the tweeter, that cannot be done, though a "tank circuit" can be employed to boost the VHF by reducing the VHF impedance, allowing more power to be delivered up high.
Art
Thanks guys. I think these filters are a bit out my reach without the measurement gear etc... Going active is looking better every day
So I threw a hard copy of the Parts Express catalog in my cart with last order and sat down with the morning coffee and I see 2 pages of super tweeters... Not sure why but I don't remember seeing that many options online... As of now, I am thinking of reaching out to PE and working a swap with the APT80 horn but I have to admit this JBL ST200 looks enticing. Selenium ST200 Super Tweeter 105db sensitivity meshes well with my setup and $5 cheaper too.
So I threw a hard copy of the Parts Express catalog in my cart with last order and sat down with the morning coffee and I see 2 pages of super tweeters... Not sure why but I don't remember seeing that many options online... As of now, I am thinking of reaching out to PE and working a swap with the APT80 horn but I have to admit this JBL ST200 looks enticing. Selenium ST200 Super Tweeter 105db sensitivity meshes well with my setup and $5 cheaper too.
I was apprehensive about adding inductors to LP the bass horns but I installed them this weekend and am somewhat startled how much it affected SQ. Very happy camper. Also dragged out my "measurement gear", old Audio Technica 4041 and EMU 404, sadly, I cannot get it to run REW but I can get True Audio to run. I might just cave and grab the USB measurement mic and go for it after a refund of the APT150s. According to my ears and True Audio, the T35's just have 2-3 db more beyond 10k even when EQing. That said, I think the APTs actually are more musical sounding. I think this is a personal preference type of thing.
Resisting all temptation to hook my Keystone along side of this setup
Resisting all temptation to hook my Keystone along side of this setup
Thanks gents. Spent more time digging and think I found the model of the horn. I think PC264 maybe. https://www.google.com/url?sa=t&rct...n=3f23590e_4&usg=AOvVaw3l_za4GE6FHz2KemMml2L2
The conical expansion PC264 is a flat front horn (circa 1999), the horns depicted in post #67 are radial semi-exponential horns with a round front edge.
The radial horns were used for the mid or the top end of the "Leviathon" series from the 1970's, as seen on the left and right in this photo:
Due to "full range" flat front cabinets, the pro sound industry largely departed from using horns with round fronts in the early 1980's, though they obviously are still "around" ;^).
Art
The radial horns were used for the mid or the top end of the "Leviathon" series from the 1970's, as seen on the left and right in this photo:
Due to "full range" flat front cabinets, the pro sound industry largely departed from using horns with round fronts in the early 1980's, though they obviously are still "around" ;^).
Art
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