I did not build them, but photos sure looks like biscuits are used.
More photos in other thread:
Simple Passive Harsch XO Using PTT6.5 and RS28F in a Waveguide
More photos in other thread:
Simple Passive Harsch XO Using PTT6.5 and RS28F in a Waveguide
Why not? It still has the highest linear Xmax of any quality 6/5" driver that I'm aware of. The midrange performance allows for for crossover slope flexibility too.
Similar SPL sensitivity to PTT6.5 and low distortion is the Scan Speak 10F. It could go to 16kHz+ even. I have been meaning to try it out with the PTT6.5 as a FAST. But, you certainly could cross over to a dome or ribbon above 2k etc for a 3 way if you want those airy shimmering bat ear frequencies.
Speaking of ribbons, while waiting for my revised TL cabinets with mitered lock joints to get built, I might play with the in baffle measurements of the PTT6.5 with the RAAL 70-20xr. That will let me get started on a XO. My guess is it’s a simple 3.5kHz LR4. One cap and one resistor to the RAAL. About the same filter used on woofer.
Speaking of ribbons, while waiting for my revised TL cabinets with mitered lock joints to get built, I might play with the in baffle measurements of the PTT6.5 with the RAAL 70-20xr. That will let me get started on a XO. My guess is it’s a simple 3.5kHz LR4. One cap and one resistor to the RAAL. About the same filter used on woofer.
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26" Apogee ribbon. It's centaur minor which is basically a superb ribbon with a shonky box glued* on for the woofer, but I like them. Room isn't big enough to do what I would like and convert the bass to OB so kicking tyres on other options. They will always be compromised with the ribbon to cone transition but at least it's well into the modal region of my little living room.
*I know they are glued on as one of mine fell off after a year in storage!
I await your crossover but how do you get around the 1.8kHz one built into to 70-20xr?
Bill, more than once in this thread I have advised against using the PTT6.5 as 'just' a woofer because its midrange performance is so far beyond the normal state of the art. As someone who still mourns the commercial demise of Apogee in your case I say go for it. I am using a ribbon and I have come to believe the PTT6.5's exceptional performance specifically helps with the "always be compromised with the ribbon to cone transition".
And there was me hoping people would try and talk me out of it
It would require some planning but I did get wife approval in principle, mainly as I tried to find another speaker that she would accept and £8k B&Os were the only thing that tickled her fancy .I've attached a rear shot of the centaurs so you can see what I am dealing with. Its 1" MDF wrapped around 4 sides and glued with what looks like bitumin then recessed at the back to glue the back panel in. The Vinyl wrap is structural! Zero bracing inside. Efficient to make for sure.
Attachments
Yes, I am waiting for the revised TL cabinets to come back so that I can do the full listening impressions again. One thing to use is expanding adhesive like PL Premium on the internal channels. Normal wood working glue like Titebond is great for furniture, but not speakers where an airtight seal is needed.
I may just use the earlier (leaky) cabinets to get a better sense of the bass and baffle step for designing the crossovers. Originally sent those back to my cabinet maker for rework. But he decided to make new ones from scratch. They are still useful for bass down to about 50Hz, but TL was designed for low to mid 30Hz extension (when not leaky).
I may just use the earlier (leaky) cabinets to get a better sense of the bass and baffle step for designing the crossovers. Originally sent those back to my cabinet maker for rework. But he decided to make new ones from scratch. They are still useful for bass down to about 50Hz, but TL was designed for low to mid 30Hz extension (when not leaky).
I have designed 2 speakers using the Purifi PTT6.5W04 and the Purifi PTT6.5PR passive radiator.
A 2-way monitor using one Purifi PTT6.5W04 and two Purifi PTT6.5PR in a passive radiator system. The two passive radiators placed on the side walls.
And a 2.5-way floor standing speaker using two Purifi PTT6.5W04 in a basreflex system.
The two designs are complete described on my website www.vcllabs.com with mechanical drawings, x-over schematics, some calculations and simulation results. The designs may be used for building for free. Can be found in the “concepts” chapter on the website.
The building of the monitor has been started by somebody and will be ready soon for the first listening tests.
There is also an idea to design a 3 way floor standing speaker using two Purifi PTT6.5W08 with each two Purifi PTT6.5PR passive radiators, all mounted on both side walls for a good force cancelling. The midrange and the tweeter on the front wall. That speaker probably will be built also.
The Purifi active and passive driver combination is a very interesting concept to realize a low F3 in a small cabinet. With 15 L internal cabinet volume F3 = 38 Hz.
With the large maximum linear excursion of +/- 10 mm for the woofer, the SPL at maximum excursion is 98 dB at 1m, full space, 38 - 20000 Hz for the 2 way monitor. And not to forget, with an incredible low HD.
A 2-way monitor using one Purifi PTT6.5W04 and two Purifi PTT6.5PR in a passive radiator system. The two passive radiators placed on the side walls.
And a 2.5-way floor standing speaker using two Purifi PTT6.5W04 in a basreflex system.
The two designs are complete described on my website www.vcllabs.com with mechanical drawings, x-over schematics, some calculations and simulation results. The designs may be used for building for free. Can be found in the “concepts” chapter on the website.
The building of the monitor has been started by somebody and will be ready soon for the first listening tests.
There is also an idea to design a 3 way floor standing speaker using two Purifi PTT6.5W08 with each two Purifi PTT6.5PR passive radiators, all mounted on both side walls for a good force cancelling. The midrange and the tweeter on the front wall. That speaker probably will be built also.
The Purifi active and passive driver combination is a very interesting concept to realize a low F3 in a small cabinet. With 15 L internal cabinet volume F3 = 38 Hz.
With the large maximum linear excursion of +/- 10 mm for the woofer, the SPL at maximum excursion is 98 dB at 1m, full space, 38 - 20000 Hz for the 2 way monitor. And not to forget, with an incredible low HD.
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