Can someone tell me how these guys manage to achieve 91dB (4ohm) sensitivity and 114dB max SPL (24dB/octave high pass at 200Hz) with a pair of 2in fullrange drivers in a tiny sealed enclosure? The crossed angle drivers is interesting if it really makes a smooth and wide polar like they show.
Hydra - High Performance Passive-Installation Speaker
– Alderwood Speakers
The mystery drivers apparently can handle 100w rms, have 5.5mm come excursion, Xmax(or Xpp), butyl rubber surround, 1.2g moving mass, 1.2T Nd magnet.
I have looked and cannot find any 2in COTS driver that can do this, assuming two 8ohm in parallel.
Almost all 2in or 2.5in drivers are 82dB sensitive. The ones that are 85dB don’t go below 250Hz and are maybe 10w power handling. The closest thing would be a 3FE22-8 but that’s a 3.5in driver.
Maybe it’s a bespoke driver, hence the $2100 (AUSD) price tag?
I did see the Dayton PC68-8, but that’s really an 83dB sensitive driver if you look at the response graph. Also can’t handle 100w and not Nd motor and Xmax is not high enough.
Hydra - High Performance Passive-Installation Speaker
– Alderwood Speakers
The mystery drivers apparently can handle 100w rms, have 5.5mm come excursion, Xmax(or Xpp), butyl rubber surround, 1.2g moving mass, 1.2T Nd magnet.
I have looked and cannot find any 2in COTS driver that can do this, assuming two 8ohm in parallel.
Almost all 2in or 2.5in drivers are 82dB sensitive. The ones that are 85dB don’t go below 250Hz and are maybe 10w power handling. The closest thing would be a 3FE22-8 but that’s a 3.5in driver.
Maybe it’s a bespoke driver, hence the $2100 (AUSD) price tag?
I did see the Dayton PC68-8, but that’s really an 83dB sensitive driver if you look at the response graph. Also can’t handle 100w and not Nd motor and Xmax is not high enough.
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Hi X,
My 2 cents. Actually what you need is only 8ohm 85db driver. 2 of that will give 91db. I guess the pro drivers is more likely the case. The 5mm excursion might be more x-mech.
Maybe something like this....
Eminence Alpha 2-8 speaker. The Eminence Alpha 2-8 is a 2" 8 ohm fullrange speaker. Alpha-2-8 is a 20 watt RMS 2" full range speaker.
If I were to do something like this I would have used 4x3Fe22 16 ohm to achieve sensitivity of 100db/watt.
My 2 cents.
Oon
My 2 cents. Actually what you need is only 8ohm 85db driver. 2 of that will give 91db. I guess the pro drivers is more likely the case. The 5mm excursion might be more x-mech.
Maybe something like this....
Eminence Alpha 2-8 speaker. The Eminence Alpha 2-8 is a 2" 8 ohm fullrange speaker. Alpha-2-8 is a 20 watt RMS 2" full range speaker.
If I were to do something like this I would have used 4x3Fe22 16 ohm to achieve sensitivity of 100db/watt.
My 2 cents.
Oon
Eros Pro - High Power Satellite Speaker
– Alderwood Speakers
There is the single driver version.
Note the free air response. Obviously this doesn't have baffle step compensation but this mirrors what oon says above. It's really an ~85dB driver @ 8 ohm.
It isn't trying to do bass, which is important, loads of 2" drivers are optimised more around trying to give as much bass as possible and sacrifice sensitivity. The frequency response measurement shows that this only goes down to 200Hz and this is without the recommended 200Hz high-pass.
Now most 2" drivers I've seen are 80-85dB @ 4ohm. Some will work well with passive radiators and give you 60-80Hz extension. They will not go loud loud but they will fill a room. The sealed box versions only give ~150Hz extension but also don't go loud.
Optimise the parameters around 200Hz extension and 8 ohms and I can see an 85dB driver being possible.
It could hit peak SPLs of 114dB with a pair, 108dB for a single. They don't claim sustained. But the 50 and 100 watt RMS power ratings are obviously bogus. Where's all the heat going to escape from? These are sealed wooden boxes where are you going to push 49 watts of heat out of it? Let alone get 49 watts of heat out of the tiny driver. Getting that amount of heat out of a computer processor requires forced air, lots of fins and a physical design that lends itself to heat conduction. A 2" driver is the opposite of this.
The 2 driver version is called the Hydra. The only fire that's going to be breathing is it's own when it catches on fire if you try and run 100 watts RMS through it.
– Alderwood Speakers
There is the single driver version.
Note the free air response. Obviously this doesn't have baffle step compensation but this mirrors what oon says above. It's really an ~85dB driver @ 8 ohm.
It isn't trying to do bass, which is important, loads of 2" drivers are optimised more around trying to give as much bass as possible and sacrifice sensitivity. The frequency response measurement shows that this only goes down to 200Hz and this is without the recommended 200Hz high-pass.
Now most 2" drivers I've seen are 80-85dB @ 4ohm. Some will work well with passive radiators and give you 60-80Hz extension. They will not go loud loud but they will fill a room. The sealed box versions only give ~150Hz extension but also don't go loud.
Optimise the parameters around 200Hz extension and 8 ohms and I can see an 85dB driver being possible.
It could hit peak SPLs of 114dB with a pair, 108dB for a single. They don't claim sustained. But the 50 and 100 watt RMS power ratings are obviously bogus. Where's all the heat going to escape from? These are sealed wooden boxes where are you going to push 49 watts of heat out of it? Let alone get 49 watts of heat out of the tiny driver. Getting that amount of heat out of a computer processor requires forced air, lots of fins and a physical design that lends itself to heat conduction. A 2" driver is the opposite of this.
The 2 driver version is called the Hydra. The only fire that's going to be breathing is it's own when it catches on fire if you try and run 100 watts RMS through it.
Thanks, Oon. I was looking for 85dB at 2.83v 2in drivers and did not find any. The ones you linked are really 82dB if you look at the curve as most of the higher SPLs are above 4kHz.
I suppose there might be an example somewhere. However, 5thElement makes a good point, where is all that heat going to go?
I made a 4x series paralllel speaker using 3FE22-8's (97dB) and put that in a horn (+10dB) and it was loud and clear.
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Well, the 91db is just the marketing dept talking. Looking at the graph they provided, it only touches 91db at the 3kHz or so. Most of it is really 85 to 90db.
At 100W it is 50W a driver, I believe it is only meant for 10s, marketing dept talking. No way you can dissipate that much heat at this size.
I believe there are other ways of achieving more 100db at 4ohm sensitivity. I remember you messing around with a 5 inch PRV driver in that sensitivity range. Putting 2 × 8 ohms would be something to the tune of 106db sensitivity. Running them with a simple 12V battery on BTL amp would have been crazy loud...
Oon
At 100W it is 50W a driver, I believe it is only meant for 10s, marketing dept talking. No way you can dissipate that much heat at this size.
I believe there are other ways of achieving more 100db at 4ohm sensitivity. I remember you messing around with a 5 inch PRV driver in that sensitivity range. Putting 2 × 8 ohms would be something to the tune of 106db sensitivity. Running them with a simple 12V battery on BTL amp would have been crazy loud...
Oon
Hi X,
The now, I think, discontinued Tangband W2 800SL is a 2" driver that could exceed the "normal" SPL expectations of a 2" driver, for 200Hz up.
The now, I think, discontinued Tangband W2 800SL is a 2" driver that could exceed the "normal" SPL expectations of a 2" driver, for 200Hz up.
Well, the single version is 50W, 88dB, 8 Ohms.
Indeed, there must be at least one number in there that is a marketing ploy.
They mention "audio-filling" in large venues...
Used as stage monitors? Hmm, I don't think so.
It seems that the laws of physics differ down under, where a little 2" driver can sound loud and amazing over a wide space.
Well, there's only one way to find out!
They offer a demonstration if you book it online. Anyone from Australia willing to book a demo?
Indeed, there must be at least one number in there that is a marketing ploy.
They mention "audio-filling" in large venues...
Used as stage monitors? Hmm, I don't think so.
It seems that the laws of physics differ down under, where a little 2" driver can sound loud and amazing over a wide space.
Well, there's only one way to find out!
They offer a demonstration if you book it online. Anyone from Australia willing to book a demo?
Here is the early version of the eros
Scroll through the pictures and on the rear panel of the speaker it says 20wRMS and 4 ohms, and the driver looks like the SB65WBAC25-4
Eros Cube Speaker | Alderwood Speakers
Scroll through the pictures and on the rear panel of the speaker it says 20wRMS and 4 ohms, and the driver looks like the SB65WBAC25-4
Eros Cube Speaker | Alderwood Speakers
The driver in the old version is exactly the SB65.
As you can see, they do have a tendency to apply "marketing speak" to their products.
The SB65 is rated at 83.5dB, but on the site, they said 87dB.
The SB65 is about $40... add a tiny little wooden box around it and charge $650?
But now, the newer version with a single driver is 8 Ohms, and the Hydra either wired in series or parallel is 4 or 16 Ohms.
So, they must have changed the driver... but keep going with the "marketing speak" !
Hence the upgraded price of $950 for the single driver unit. Geez....
I hope they used some dowels with all those layers of ply. Otherwise one sharp knock and you've got yourself a lovely pair of agogos.
The old version with the visible cone is definitely an SB65. I also see that there is a very small aperiodic vent in the back.
I don’t fault them for charging whatever they want but the specs need to be realistic and honest. Speakers for professional architectural applications are usually expensive. Depending on how many one needs installed, price may or may not be an issue. I feel like these are aimed at niche applications where they need unobtrusive speakers that look like accent lighting cubes.
I don’t fault them for charging whatever they want but the specs need to be realistic and honest. Speakers for professional architectural applications are usually expensive. Depending on how many one needs installed, price may or may not be an issue. I feel like these are aimed at niche applications where they need unobtrusive speakers that look like accent lighting cubes.
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It works for me too. If it did not, speaker design for multi ways would have real problems.
Nice work Pelanj! I was going to make the same thing but seems you have beat me to it - can you share the CAD files?
I would just 3D print it in 3 pieces. Each cube housing and the V holder. Volume is small so probably an aperiodic vent might allow a little deeper extension down to 200Hz.
Another option that would increase the volume is to make it a single block with two 120deg angled faces. They would have a shared volume but that’s fine. Could allow increase to maybe 0.4L combined? Print as one big structure with internal bracing via high porosity infill to act as a “foam”.
Btw,
Has anyone tried this PC68-8 driver? Looks pretty good on paper and reviews all positive. Fiberglass cone is nice.
Dayton Audio PC68-8 2-1/2" Full-Range Poly Cone Driver
I would just 3D print it in 3 pieces. Each cube housing and the V holder. Volume is small so probably an aperiodic vent might allow a little deeper extension down to 200Hz.
Another option that would increase the volume is to make it a single block with two 120deg angled faces. They would have a shared volume but that’s fine. Could allow increase to maybe 0.4L combined? Print as one big structure with internal bracing via high porosity infill to act as a “foam”.
Btw,
Has anyone tried this PC68-8 driver? Looks pretty good on paper and reviews all positive. Fiberglass cone is nice.
Dayton Audio PC68-8 2-1/2" Full-Range Poly Cone Driver
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Here is the F360 export and also STEP file. I hope it is understandable🙂 I added a driver recess to the front. Also, it is made for 15 mm plywood construction, but anyone can modify to his own liking.
Thank you, Pelanj!
I think the 3FE22 is the perfect driver for this application rather than a smallish 2in.
I think the 3FE22 is the perfect driver for this application rather than a smallish 2in.