Hi all,
This is a bit more of a thought at the moment than anything.
I have a pair of alpair 12pw woofers lying around which were originally going to be used in a WaW set-up, but for a few reasons I don't think that'll be happening anymore.
I am curious about true ribbon tweeters and I'd like to see what they can do. I am concerned with using them in a two-way as I understand they don't usually reach too low.
The alpair 12pw can reach high with no issues, but I'm concerned about directivity if crossing about 3k+
I was wondering what everyone's opinion would be on this? The 12pw measures about 13cm from edge to edge, measuring from the edge of the surround. It's quite a flat profile cone, but there is no directivity data unfortunately.
My budget is only around £100 per tweeter so I was originally considering the fountek neo cd3.0 as I understand it's quite a popular unit
So in summary, I would like some opinions on the following:
1) Would crossing at 3-4khz cause noticable issues with directivity?
2) Are there any ribbons that can reach lower than typical?
3) I am also concerned about time alignment of the drivers and I don't know if I'd be able to do this passively. Any input on this is welcome
4) Any honest opinions welcome as this would be my first ever speaker/xover design. I don't mind some trial and error, as long as the driver selection is a good on paper and it has the potential to be a good speaker
Thanks
This is a bit more of a thought at the moment than anything.
I have a pair of alpair 12pw woofers lying around which were originally going to be used in a WaW set-up, but for a few reasons I don't think that'll be happening anymore.
I am curious about true ribbon tweeters and I'd like to see what they can do. I am concerned with using them in a two-way as I understand they don't usually reach too low.
The alpair 12pw can reach high with no issues, but I'm concerned about directivity if crossing about 3k+
I was wondering what everyone's opinion would be on this? The 12pw measures about 13cm from edge to edge, measuring from the edge of the surround. It's quite a flat profile cone, but there is no directivity data unfortunately.
My budget is only around £100 per tweeter so I was originally considering the fountek neo cd3.0 as I understand it's quite a popular unit
So in summary, I would like some opinions on the following:
1) Would crossing at 3-4khz cause noticable issues with directivity?
2) Are there any ribbons that can reach lower than typical?
3) I am also concerned about time alignment of the drivers and I don't know if I'd be able to do this passively. Any input on this is welcome
4) Any honest opinions welcome as this would be my first ever speaker/xover design. I don't mind some trial and error, as long as the driver selection is a good on paper and it has the potential to be a good speaker
Thanks
Just a thought. What about a planar ribbon tweeter instead of a true ribbon? For example the Radian LT2 + it's waveguide. Recently I compared the bigger LT3 to the Viawave GRT-145 true ribbon and the planar ribbon sounded cleaner (and better) to my ears, although both measures and sounds very good down to 2kHz or even lower (they was EQ-ed to the same response).
The LT2 measures really good too (can be crossed about 2kHz), and the small waveguide is a good match directivity wise to a small midwoofer like the Alpair 12PW. Moreover the flatter impedance of the planar ribbon helps the passive filtering.
https://radianaudio.com/products/lt2-planar-ribbon?variant=20538618216510
https://audioxpress.com/article/tes...r-and-waveguide-from-radian-audio-engineering
The LT2 measures really good too (can be crossed about 2kHz), and the small waveguide is a good match directivity wise to a small midwoofer like the Alpair 12PW. Moreover the flatter impedance of the planar ribbon helps the passive filtering.
https://radianaudio.com/products/lt2-planar-ribbon?variant=20538618216510
https://audioxpress.com/article/tes...r-and-waveguide-from-radian-audio-engineering
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I haven't heard the Fountek ribbons, but how about the horn loaded one, the 3.5H? The horn will control the horizontal directivity (although its mouth is quite small, so you'd still need to cross quite high, to avoid losing the directivity pattern).
I am using the Fountek FP-2. 14 pieces per side in a line array...Theysound remarkably well and I am actually playing them either with a 12db bessel or even 6db xover ...you will be surprises how well this goes. There have been some nice measurements on using them with only a 6db xover from a DIY hardcore speaker build in denmark, who was surprised how well distortion etc react if only one cap is already involved and i can echo that. Just try...
That looks like a nice suggestion, thanks. I am happy to consider other types of tweeters too, these do look interesting. Is there any reason why you suggest the lt2 instead of the lt3? It looks like the lt3 can reach a little lower but does cost a little more.
Thanks for the suggestion. I have seen the 3.5H, it may be a better option than the cd3.0
I didn't realise the neoX range are bigger, I'm a bit confused by founteks naming scheme and their prices are up and down, for example the cd2 costs more than the cd3, but the cd1 is the cheapest. I'll take a look at the x range
I couldn't find the FP-2 either, curious to see what it is
Yes, the naming is confusing! The Fountek datasheets have the ribbon dimensions. The neoX series seem to have 12mm wide elements, which is 50% wider than the neoCD series.
Be aware that the sound of the Fountek series do vary. I prefer the old series, but before investing big time, compare the sound between those...but once you found your drug, its hard to go back to any normal dome tweeters...just too slow and not natural enough.
The LT3 seems to have a strange FR dip around 3kHz that don't show up on the datasheet, although I measured only without the waveguide. The LT2 have a reasonably FR (as we can see in the audioxpress measurement) that don't necessarily needs DSP EQ. Also I think the LT2 is more than enough for a small midwoofer like the Alpair 12PW.
https://www.diyaudio.com/community/threads/radian-lt3-measurements.385832/post-7039334
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This is the site I meant...you need to navigate a bit around, there are more tests of ribbons...thisis just an entry point:
http://www.troelsgravesen.dk/Tweeters_dist-test.htm
http://www.troelsgravesen.dk/Tweeters_dist-test.htm
Greets!
Ideally need to be within a 1/4 WL of the XO point to sum 'close enough' in the near-field and at worst at 1.0 diameter, so 34400/4/(2.6+10.35) = ~664 Hz, 34400/pi/(2.6+10.35) = 845.5 Hz, so in your 'mind's eye' these have to ideally shrink to the calc'd relatively tiny 3-4 kHz spacings.
TD wise, at these long listening distances one can usually just vertically align the driver's VCs and at worst use whichever the tweeter's polarity sounds best if not having a DSP in the budget to digitally XO/align them; otherwise, for more accuracy calculate the number of XO degrees offset behind this point to find the total offset for the tweeter to be in phase.
Hi GM, thanks for your input.
I know it's basically impossible to get the C-C spacing 1/4 of the XO frequency in a two way (unless using something like a full range). At 3khz the drivers would need to be about 3cm apart so I imagine it's basically impossible due to the size of the ribbons
I was basically considering forgetting about this constraint and just placing them as close together as possible. Unfortunately as I think about this, I think the 12pw basket is about 7" which pushes the distance even further than one wavelength at 3000hz.
With this being said I have a cheap pair of 8" monitors that cross to a tweeter at 2000 hz and they sound okay so I'm not sure where that leaves me
And btw...my biggest concern would not be cross iver frequencies or placements...it is having a low mass, fast driver next below the ribbons which can come near to their impulse response/way of producing tones...which brings you down to 4gr to mac 10gr. Devices. I use 4gr 4" hexacone midrangers...18 of them in a line array...these guys integrate reasonably...for a dappolitto the 5" eton hexacone woukd work as well...but a 8" with a ribbon ? Thats a stretch.
... But the Alpair 12PW is only an 8" if you go by the diameter of the (very wide) surround. Its Sd is 147cm2 - more like a typical 6". Mass is 11.7g - not as low as your hexacones, but not too bad.
No, that is not bad, I agree...there are as well some very nice paper cone drivers with very low mass, which I love as well because of their nice natural sound...and match well with ribbons...at the higHENd in Munich i loved the demo of soundkaos.com...which combine excatly that.
If it helps, here are some interesting material.
Fountek and Viawave are true ribbon tweeters, aka a metal foil suspended at the ends and held in place in a magnetic field, while Radian is a fully sealed Planar Magnetic Quasi Foil type - the later is better which is explained in the video bellow 🙂
https://audioxpress.com/article/thin-film-high-frequency-transducers-part-1-the-advantages
https://audioxpress.com/article/thi...sducers-part-1-the-lt2-lt6-ribbon-transducers
Fountek and Viawave are true ribbon tweeters, aka a metal foil suspended at the ends and held in place in a magnetic field, while Radian is a fully sealed Planar Magnetic Quasi Foil type - the later is better which is explained in the video bellow 🙂
https://audioxpress.com/article/thin-film-high-frequency-transducers-part-1-the-advantages
https://audioxpress.com/article/thi...sducers-part-1-the-lt2-lt6-ribbon-transducers
Thanks for sharing those articles and the video, very interesting to see. I have not really heard much about these planar ribbon tweeters until I started this thread but definitely worth looking into it seems
Fair enough. I just noticed the lt3 can go lower which was the benefit in my mind. The freq response does look all over the place and probably not ideal for a beginner like me. The lt2 doesn't seem too bad freq response wise. It's one to consider if I can figure out a good crossover point, I still need study this area a bit more
The reason I dropped in was to check peoples opinion on the LR2, AudioXpress measurement is looking really good... and compared to some very expensive Beryllium and Diamond dome tweeters, the LR2 looks like a champ. Especially in the transient department. The LM8K looks alright as well, so those two drivers in combination with SB Audience ROSSO-6MW150D 6" midwoofer in an Open Baffle U-frame Line-Array is very appealing.