@Draki; thanks, I had misunderstood. I thought the rear facing drivers were in the same vertical line as the forward facing ones but they are off to the side, hence the offset 🙄.
Apologies CharliLaub for dragging your thread OT. I’m looking forward to the article too. I’m interested because I also want my planned speakers to be the end game for me.
Apologies CharliLaub for dragging your thread OT. I’m looking forward to the article too. I’m interested because I also want my planned speakers to be the end game for me.
If you go high end. Then the scan speak 32w/4878t00 has lowest low bass distortion i have seen any tests. And it is good to have high xmax at open baffle use.
Cheap solution would be twin ciare hs251. You can connect voice coils series to get high qts. Also woofer has low low bass distortion and high xmax.
Cheap solution would be twin ciare hs251. You can connect voice coils series to get high qts. Also woofer has low low bass distortion and high xmax.
Yes indeed. The 32W/4878T00 looked very impressive in the VoiceCoil review from 2013 . The motor is amazing. I assumed that the 32W/4878T11 has a similar motor but with flux focused in a narrower gap but I have not seen Klippel tests that would verify that. They both cost almost US$700, so much more expensive than the Seas L26RO4Y but also 12" vs 10".
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Gap is the same, the voicecoil is shorter.
I've used many T00, they are a stunning driver. The copper ring in the gap is huge.
I've used many T00, they are a stunning driver. The copper ring in the gap is huge.
For a woofer It has nice and extended response past 1KHz.
I'm haven't seen any real stress tests. ie. measurements purely focused on performance in the bottom octave.
Voice Coil test bench (2013) measured @94dB @1m from 50Hz and up
Klang and Ton measured @95dB @1m again, from 50Hz and up.
But 50Hz and up, and at those SPLs, well it’s relatively gentle (<10W), its hard to separate from other good 12" subwoofers.
Only Hobby Hifi measured @20hz and up (90dB@1m) and in that one it didn't really distinguish itself.
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Did you consider the Peerless NE315? No go if Tymphany would not to do a production run, but since it's for publication in a design, I'd not be surprised if they would.
I wonder if they ever were in the business. Vifa started as OEM supplier. I think it’s only because a German company brought the brand to the DIY scene that we may enjoy them for close to 40 years now.
A great book;
Or coffee table book for loudspeaker nerds:
https://audioxpress.com/article/the-danish-loudspeaker-100-year-anniversary-book
In my view; Peerless ceased to be a Danish manufacturer the day an American group of investors bought out Danish Sound Technology; (a holding company of Scan-Speak, Vifa and Peerless) and renamed it Tymphany:
This was almost 2 decades ago-
http://www.zaphaudio.com/tymphany.html
Some Vifa employees left and respawned as Wavecor. Some Peerless employees left, formed other compnanies and are now at Purifi. Some Scan-Speak employees left and eventually bought back the tooling/rights for Scan-Speak drivers. Some Scan-Speak employees formed Gamut (loudspeaker manufacturers) or ScAR (Scandinavian Audio Research) or Danesian Audio. The latter formed a partnership with Sinar Baja Electric and became SB Acoustics.
It’s all very complicated because the Denmark has a rich history and heritage as one of the pioneers of the dynamic loudspeaker with voice coil. In fact Vifa was formed out of some disagreements of SEAS, and Dynaudio, Scan-Speak and AudioTechnology were all founded by the fellow company.
Up until the late 20th century loudspeakers was Denmark’s third biggest export by revenue.
Or coffee table book for loudspeaker nerds:
https://audioxpress.com/article/the-danish-loudspeaker-100-year-anniversary-book
In my view; Peerless ceased to be a Danish manufacturer the day an American group of investors bought out Danish Sound Technology; (a holding company of Scan-Speak, Vifa and Peerless) and renamed it Tymphany:
This was almost 2 decades ago-
http://www.zaphaudio.com/tymphany.html
Some Vifa employees left and respawned as Wavecor. Some Peerless employees left, formed other compnanies and are now at Purifi. Some Scan-Speak employees left and eventually bought back the tooling/rights for Scan-Speak drivers. Some Scan-Speak employees formed Gamut (loudspeaker manufacturers) or ScAR (Scandinavian Audio Research) or Danesian Audio. The latter formed a partnership with Sinar Baja Electric and became SB Acoustics.
It’s all very complicated because the Denmark has a rich history and heritage as one of the pioneers of the dynamic loudspeaker with voice coil. In fact Vifa was formed out of some disagreements of SEAS, and Dynaudio, Scan-Speak and AudioTechnology were all founded by the fellow company.
Up until the late 20th century loudspeakers was Denmark’s third biggest export by revenue.
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@tktran303 Thanks for mentioned the book. It's a free PDF download that you can access at the audioXpress link above. I never realized how many amazing audio companies originated in Denmark!
Interesting project CharlieLaub. I have experience with 2 of the drivers mentioned. I have used the 2layer voice coil variant of the Seas L26ROY. This Seas has tons of excursion and also low 2nd harmonic distortion in the 30-40hz range. This helps out in the real world as most domestic rooms with a 8-9 ft ceilings have room modes in the 60-80hz range. However to be honest, I do not like the upper bass from the Seas it has a distorted metallic edge to it.
Multiple Purifi 8" or waiting till the 10" is available would probably be my choice for your project. Dipole bass is very demanding of the driver and the Purifi remains clean at high drive levels. I have compared the IMD of the Purifi 8" to the Seas 10" and the Purifi is cleaner in all tests. I don't foresee the 4 layer Seas to do better in IMD as according to Seas the 2 layer variant has lower distortion. https://www.diyaudio.com/community/...lation-distortion-testing.387690/post-7249113
I don't have experience with the LO12 but I have used the AE IB15HT in dipole and the AE SBP12a in a sealed box. To give an idea of the demands of a dipole system 2 15" woofers about equal a single monopole 12". Attached is the 30 and 72hz IMD test of a pair of AE IB15HT woofers compared to a single AE SBP12a in a 85 liter sealed box. I have used the trick that Steinway uses to reduce even order distortion and one of the 15" drivers is reversed mounted with polarity flipped. You see in the graph that the 2nd harmonic distortion of 30hz(60hz) is almost lost in the noise for the dipole. The IMD3 at 132hz is about the same about -35db in all test. I'm not sure about using an underhung topology in a dipole, Mr. Linkwitz dismissed it many years ago: https://www.diyaudio.com/community/...st-bass-i-have-ever-heard.163914/post-2209229
I have no experience with ScanSpeak drivers but comparing the ScanSpeak 32W/8878T11 to the Purifi 8" on HifiCompass the Purifi has lower IMD levels.
Multiple Purifi 8" or waiting till the 10" is available would probably be my choice for your project. Dipole bass is very demanding of the driver and the Purifi remains clean at high drive levels. I have compared the IMD of the Purifi 8" to the Seas 10" and the Purifi is cleaner in all tests. I don't foresee the 4 layer Seas to do better in IMD as according to Seas the 2 layer variant has lower distortion. https://www.diyaudio.com/community/...lation-distortion-testing.387690/post-7249113
I don't have experience with the LO12 but I have used the AE IB15HT in dipole and the AE SBP12a in a sealed box. To give an idea of the demands of a dipole system 2 15" woofers about equal a single monopole 12". Attached is the 30 and 72hz IMD test of a pair of AE IB15HT woofers compared to a single AE SBP12a in a 85 liter sealed box. I have used the trick that Steinway uses to reduce even order distortion and one of the 15" drivers is reversed mounted with polarity flipped. You see in the graph that the 2nd harmonic distortion of 30hz(60hz) is almost lost in the noise for the dipole. The IMD3 at 132hz is about the same about -35db in all test. I'm not sure about using an underhung topology in a dipole, Mr. Linkwitz dismissed it many years ago: https://www.diyaudio.com/community/...st-bass-i-have-ever-heard.163914/post-2209229
I have no experience with ScanSpeak drivers but comparing the ScanSpeak 32W/8878T11 to the Purifi 8" on HifiCompass the Purifi has lower IMD levels.
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When considering the AE LO series, be aware of one thing.
They do not like being overdriven, short underhung coils, so the THD goes up very quickly after a certain amount of excursion.
And it might be noticeable in some cases. That was the conclusion from Nick Mckinney (the designer) in a thread i read recently, just can't remember where.
I assume this might have been the older measurements your referenced to with the 15LO?
What i mentioned is quite visible in the Xmax measurements, as THD% if you compare the TD15 LO and X there.
https://sites.google.com/site/drivervault/driver-measurements/15
The upper end looks good, but it has the traditional cone/surround/frame dip as the other TD driver exhibits, just less prominent.
Not so different from the TD15M with it's quoted 6mm xmax, as shown at databass and a few other measurements, the suspension is not linear at those excursions. And the original spec of 3,3 mm from Lambda is more in it's comfort zone.
They do not like being overdriven, short underhung coils, so the THD goes up very quickly after a certain amount of excursion.
And it might be noticeable in some cases. That was the conclusion from Nick Mckinney (the designer) in a thread i read recently, just can't remember where.
I assume this might have been the older measurements your referenced to with the 15LO?
What i mentioned is quite visible in the Xmax measurements, as THD% if you compare the TD15 LO and X there.
https://sites.google.com/site/drivervault/driver-measurements/15
The upper end looks good, but it has the traditional cone/surround/frame dip as the other TD driver exhibits, just less prominent.
Not so different from the TD15M with it's quoted 6mm xmax, as shown at databass and a few other measurements, the suspension is not linear at those excursions. And the original spec of 3,3 mm from Lambda is more in it's comfort zone.
Studley, good question. Asymetric nonlinearity, such as having more motor force when going out versus going in is one of the causes or even order distortion. If you flip one driver and reverse the polarity, one driver is moving in while the other is moving out. Any asymmetries can therefore be cancelled to a certain degree. This causes causes a reduction of even order distortion.
OK thanks for that. Has this type of asymmetric behaviour been measured in many drivers and is it considered to be a significant source of distortion? I use the word significant in the sense of worthy of addressing.
I confess I thought the Model B arrangement was purely to allow a more compact construction.
I confess I thought the Model B arrangement was purely to allow a more compact construction.
Studley, yes you can see it here https://audioxpress.com/article/test-bench-the-sdx10-home-audio-woofer-from-css-audio in figure 5 in a klippel test there is more motor strength BL going out then in. Look for high 2nd harmonic distortion in figure 11. The Seas l26roy is much more symmetrical in BL and KMS and has lower 2nd order distortion. https://audioxpress.com/article/test-bench-the-l26roy-10-subwoofer-from-seas
Compare also to SEAS L16ROY https://audioxpress.com/article/test-bench-the-l26roy-10-subwoofer-from-seas
I can't see connection of Bl symmetry and H2/H3 relation, comparing CSS and SEAS. But SEAS has generally much lower distortion.
I can't see connection of Bl symmetry and H2/H3 relation, comparing CSS and SEAS. But SEAS has generally much lower distortion.
Juhazi,
Maybe page 29 will help?
https://www.klippel.de/fileadmin/_m...linearities–Causes_Parameters_Symptoms_01.pdf
Maybe page 29 will help?
https://www.klippel.de/fileadmin/_m...linearities–Causes_Parameters_Symptoms_01.pdf
What was it about the pro drivers you tried that didn't work so well? I've been thinking about a similar OB woofer project. I haven't bought drivers yet, but I'd been thinking that pro drivers were the obvious way to go!