I’ve just built some PAP Duet clones (well, as close as I can without forking out on the Voxativ full-ranges!) using Tang Band TB-1808 (good up to 20khz) and Eminence Alpha 15A drivers (crossed at around 500Hz)
While they’re settling in very well indeed, and dispelling any myths that 300b tubes don’t ‘do’ open baffle, I’m itching to see what the inclusion of a proper tweeter might do. I managed to get hold of a pair of Scanspeak Illuminator (example here https://www.hificollective.co.uk/co...t=The compact size is one,Ratio fs/Qts 558 Hz)
My intention is to mount the tweeters facing upwards and attenuate them by ear so that they don’t interfere with the point source I’m getting from the Tang Bands. I’m also intending to filter them to start coming on song around 3kHz and leave them to do their own thing up to top end of 30kHz, leaving the front-facing TB’s to do their thing up to 20kHz
Does anyone have experience of this type of endeavour, and can you help a bit of a noob understand the pitfalls in where I’m attempting to go here please?
I've attached the existing XO design if that helps anyone to provide advice
Cheers!
While they’re settling in very well indeed, and dispelling any myths that 300b tubes don’t ‘do’ open baffle, I’m itching to see what the inclusion of a proper tweeter might do. I managed to get hold of a pair of Scanspeak Illuminator (example here https://www.hificollective.co.uk/co...t=The compact size is one,Ratio fs/Qts 558 Hz)
My intention is to mount the tweeters facing upwards and attenuate them by ear so that they don’t interfere with the point source I’m getting from the Tang Bands. I’m also intending to filter them to start coming on song around 3kHz and leave them to do their own thing up to top end of 30kHz, leaving the front-facing TB’s to do their thing up to 20kHz
Does anyone have experience of this type of endeavour, and can you help a bit of a noob understand the pitfalls in where I’m attempting to go here please?
I've attached the existing XO design if that helps anyone to provide advice
Cheers!
Essentially you're widening the treble dispersion. How would you describe your treble now?
Hi Allen, I'd describe it as all being there up to a certain point (i'm imagining that's 20khz, but without the ability to measure I'm guessing!), but that there's a missing top end sparkle which I'm accustomed to. The difference between my streamer/DAC and TT in my Living Voice speakers is significant, and in the top end. With these baffles the presentation is very similar indeed, which leads me to believe that there are certain top-end frequencies missing from the baffles. In all other areas these baffles trounce my LV's, which is saying something!!!
You can increase the treble by equalising it, such as by using a tone control. You can increase the treble by adding more angles. They will sound different.
I guess what I'm saying is that in your shoes, I'd like to know how it sounds with the treble turned up to the needed level so I can fairly compare to any added tweeter.
I guess what I'm saying is that in your shoes, I'd like to know how it sounds with the treble turned up to the needed level so I can fairly compare to any added tweeter.
I'm not keen on adding more to the signal path of the existing circuit to EQ the existing drivers, and by exploring the required 'voicing' resistor (2.2 / 2.7 / 3.3 ohm options) on the TB1808, the outcome is not how much further extended up the treble frequencies one can achieve, but how loud the natural frequencies of the TB1808's mids and treble are. My experience is that with the 2.2ohm, the mids/treble are just too 'shouty' - ie they are quite a bit louder than the bass, and with the 3.3ohm, they're just right. This is what leads me to believe that the issue lies in the fact that the frequency extension of the TB1808 does not go beyond 20khz
My observation with my PAP Trio 15 being the same that the very top end sparkles are indeed missing or muffled when compared to my Klipsch Forte IIIs. I am not sure if we can get it into the PAP with the W1808 but would like to see your experiments on the resistance.
Thanks and by the way the baffles are looking very good.
What we hear beyond 20kHz is not very important. More important is the levels of the treble below 20kHz.
Some fullrange drivers may have breakup issues in the lower treble which might explain the shoutiness. Sometimes you can notch these out, sometimes you can listen off-axis where they are more balanced. You can even cross them to exclude the issue altogether. Yes, I realise this is not the point of fullrange drivers and these are some of the things to consider when selecting one.