I have a pair of BMS 4552NDs that I'll sell cheap. Bought them off of Ivan over at Danley Sound Labs, via eBay, quite a while ago.
Lovely compression driver, but the Eminence N151M is nearly a clone and costs a lot less.
https://www.diyaudio.com/community/threads/improved-saw-lens.350889/post-6122375
N151M on the venerable QSC waveguide is still the best measuring waveguide I've ever seen, better than anything I've been able to come up with. Main reason I don't run them myself is because I still love me some Unity horns.
If anyone is interested in any of this stuff, I'm doing a bunch of spring cleaning and I'd happily part with them.
Obviously yes, but some people seem to believe that there's very little or no discernible difference between compression drivers.
The horn/waveguide alone (+ the crossover) can make or break the driver, that's true, but I've also heard a very different sound (signature) from the same driver with the same horn in an active PA cab versus a (passive) hi-fi speaker powered by a tube amp.
Then there is the measurement-driven brigade who seem to be listening through the screen displaying the response graphs and who sometimes seem to believe that THD doesn't matter as long as it remains below certain threshold(s).
However, it's the distortion signature that determines whether the reproduction is perceived as natural (real).
In another thread I came across a post in which someone apparently requested (strict) criteria for the correct low pass in relation to (cone) breakup...
Well... if these existed we'd probably be living in an AI simulation instead of a natural simulation (illusion).
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No, not in particular, because I referred to 'the chain' (+ intended use etc.) in the context of coherence/interplay.
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There are exceptions in some cases.
Radian 475BE is less clean then the alu. Diaphragm version.
Faital HF 1440 and ND3N/NSD3N top end, are both as well behaved or better then some of the large diaphragm BE drivers.
Might be worth trying something like T34B, M74B /M142B.
Or one of the Pioneer exclusive /TAD Polymer Graphite cone woofers/midranges, Tad TM-1201 fx.
It's as close as you would come in characteristics of materials.
Ease of manufacturing, price, availability, and of course profit margins, as 90% of all parts are made in China these days. Regardles of where assembly is done.🙃
And in 100 years of R&D, the basic structures of transducers are very similar to what they were 50 or 100 years ago, compression drivers are a good example in general. Not counting the latest coaxial cds, axi2050 etc.
Audio R&D is still in the stone age, compared to most technology advances the last 100 years so.
Most popular material in CD's today is Titanium and polymers that did not exist in drivers 100 years ago.
And i don't argue that a pulp cones has some good qualities, again most are today mixed with different materials.
Also might me much less detrimental to performance as the pulp can be mixed from different sources with less negative effects.
Still don't know of any mfg. Except Pioneer/TAD owning they're own pulp plantations for consistency🙃
While a metal diaphragm needs precise and consistent material properties and heat treatment procedures, that must be exactly replicated for each batch to give the same result.
Agree with most of your findings/statements.
Radian drivers are interesting, especially the 7-series, but QC appears to be lacking compared to the big brands.
A 7-series neo driver is also used in this relatively simple Supravox 3-way, which quite a few people seemed to like at Munich High-End:
The HF1440 has been highly anticipated, although many people generally seem to prefer the HF108 > I've seen a lot of used HF1440s for sale over the years.
ND3N/NSD3N are without a doubt among the best drivers.
Imo (from experience) the best (sounding) woofers are often the budget/basic models of renowned manufacturers.
New 'technology' rarely translates to better (sound) > more often to cost reduction.
Yes, you can design a driver with a DNA-helix-inspired phase plug that measures well, but does it sound noticeably better than a traditional entry level driver? I wouldn't be surprised that Crowe's subjective findings are primarily caused by the phase plug. There's a lot science related to spiral/vortex acoustics, but next to none of this has to do with audio.
Radian drivers are interesting, especially the 7-series, but QC appears to be lacking compared to the big brands.
A 7-series neo driver is also used in this relatively simple Supravox 3-way, which quite a few people seemed to like at Munich High-End:
The HF1440 has been highly anticipated, although many people generally seem to prefer the HF108 > I've seen a lot of used HF1440s for sale over the years.
ND3N/NSD3N are without a doubt among the best drivers.
Imo (from experience) the best (sounding) woofers are often the budget/basic models of renowned manufacturers.
New 'technology' rarely translates to better (sound) > more often to cost reduction.
Yes, you can design a driver with a DNA-helix-inspired phase plug that measures well, but does it sound noticeably better than a traditional entry level driver? I wouldn't be surprised that Crowe's subjective findings are primarily caused by the phase plug. There's a lot science related to spiral/vortex acoustics, but next to none of this has to do with audio.
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Yeah i have seen a few too many examples of bad internals and issues with Radians to want to use my own money on them.
Also seen some horrendous 950 measurements, as they have clearly used not matching 'throat adapters' in some of them (being a 951 1,4" with adapter).
The 745 looks like one of the better options they have indeed.
Yeah the HF1440 has a smooth and well behaved top end, BUT just as the HF10AK it has a hole in it's response between 1-2khz, which makes it problematic with a passive XO, straight in the most sensitive area. Not really what i would advice most to buy.
The HF108 is easy to use and goes low for a 1", has some slight resonances around 5k, and in the top octave. But not really offensive in any way.
Hard to argue about that.
Very often the addition of demodulation, shorting rings, massive baskets, optimization for high excursion etc. is implemented in a way that leaves a lot to be desired.
Copper sleeves are hard to find sadly, as they require more expenses in magnets, but rarely have much negative effects.
Yes your absolutely correct in that too, a example would be JBL's direction for the last 20+ years.
Those new DH drivers also has some downright nasty looking impedance traces, showing strong resonances and breakup.
That is enough for me to not wanna explore them, especially when there are several good options for decent prices.
Although it is typical @B&C compression drivers.
As for the vortex phase plug geometry itself, that is outside the realm of what i feel adequately knowledgeable to have a opinion about🙂
Great post!
A couple of observations:
- Gedlee Summas were the first time I bought a speaker that cost a lot of money. Basically I was working for a software company that did an IPO and I got a windfall of money when the company went public. I spent most of the money on something practical (bought a house) but I set aside some money to buy something "impractical and fun." That's how I went from using $300 JBLs as my reference, to the Gedlee Summas. I really like the Summas a lot, and they image like you wouldn't believe, but they always felt like massive overkill in my house. The woofer in the Summas is capable of producing something like 127dB of output. I ended up selling them because my wife didn't like how big they were. The woofer in the Summas is NOT cheap, it's basically the kind of thing you might use for a nightclub where it's belting out 120dB for hours at a time, every day of the week. Years after I sold the Summas, I bought a pair of Yamaha DXR12s on Craigslist. Completely on a whim; they were $400 each and I figured they might give me a "fraction" of what the Summas can do. Astoundingly enough, they are really REALLY nice. No, they're not competitive with well engineered $5000 speakers, but for $800? They're ridiculously good. I've never heard an Econowave, but the DXR12 reminds me a lot of it. A great waveguide combined with an affordable compression driver and possibly the cheapest woofer you've ever seen. If you open up the DXR12, it's using a woofer that basically looks like a Chinese knockoff of an Eminence Alpha 12. It is NOT fancy. My hunch, is that the DXR12s aren't even breaking a sweat when they're playing at 100dB. So, yeah, the components are cheap, but there's so much headroom, you likely will never know in a home setting. It's true that shorting rings and dual gap motors can reduce distortion, but another way to reduce distortion is to just use a woofer that's big enough that you don't need to give it more than 5-10 watts of power to get loud.
- I've made some threads about DIY compression drivers, and I've created dozens of phase plugs for dozens of tweeters. I can't quite figure out why this is, but there's something about a phase plug that seems to make music sound a bit dull even when the response is flat. This was especially apparent when I made phase plugs for the SB Acoustics 1" aluminum tweeter. (SB26?) In March of 2023 I published a thread about a Unity horn that I made, and that speaker just had something "off" about it that I struggle to describe. I haven't been doing a lot of stuff with audio because my current job is way too much work, but if I were, I think I'd probably lean towards using a ring radiator compression driver if I were going to make a waveguide in 2024. The Yamaha DXR12 uses literally the cheapest compression driver that Celestion sells, and it sounds exceptional. Again, I don't want people to run out and buy a pair and then get mad at me if they don't like them. The Yamahas aren't the greatest ever, they're just really good for $800. A quick peek at eBay shows that they're currently selling for about $1400, so the value proposition isn't quite as good these days.
Another question: is there a 3D plan for a 8" ~90° horn out there that you could download and 3D print? I just ordered another 1" compression driver to test and need a horn to couple it to, but don't want to buy one if I don't have to.
I'm hoping the group buy here of Peerless Tymphany DFM-2535R00-08 will do the job.
I'll let you know in ~February.
Until then I have to rough it with BMS4550 or Vitavox S2 drivers.
I'm quite tempted by the BMS4552ND and the Eminence N314T (1.4"), but must resist.
How many pairs of compression drivers does a guy need?🙂
I'll let you know in ~February.
Until then I have to rough it with BMS4550 or Vitavox S2 drivers.
I'm quite tempted by the BMS4552ND and the Eminence N314T (1.4"), but must resist.
How many pairs of compression drivers does a guy need?🙂
Thanks. I can print up to 25cm corner length with my Bambu P1S; but I guess I can cut off half a cm on each side without it screwing up the acoustic properties too much.
By any chance, did you have the opportunity to take polar measurements?
Do you know where I can find this data re: SB26ADC?