What is the advantage of that compared to a high quality small cone? Surely breakup isn't usually the driver, rather the beaming, and 2.5k isn't special.
The datasheet here looks OK - and its certainly not expensive - but to me that looks like a 5" midwoofer with a big dustcap, Dynaudio style.
Sadly no off axis plots, which I'm generally suspicious of.
Why is that in and of itself useful? The datasheet is not suggesting anything more than a competant 5" midwoofer. Fs isn't remakable, nor the on-axis frequency response, nor efficiency, and we have no off-axis or distortion data.
It looks reasonable value. Is it better than the SBAcoustics drivers of similar size and cost - why?
I have a question (its actually that) related to the frequency ranges quoted and used for domes. I'm not trying to troll.
If we look at the way ATC, Volt, Bliesma midranges are used - then the lower end seems to correlate to Fs, and the crossover is using the natural rolloff as part of the deal.
OK but - for a cone midrange I'd normally see a recommended crossover at 2x or 3x Fs. Maybe even 4x, where we're looking at 75 to 300 or so.
I can understand why this is given that typically when we see actual distortion data, it increases quite rapidly below 2x Fs.
I have not seen distortion measurements for 'good domes'. Possibly this is because they are older and such measurements are a more modern take and easier to do.
Why is it OK to use a dome midrange with XO at Fs but not a cone?
If we look at the way ATC, Volt, Bliesma midranges are used - then the lower end seems to correlate to Fs, and the crossover is using the natural rolloff as part of the deal.
OK but - for a cone midrange I'd normally see a recommended crossover at 2x or 3x Fs. Maybe even 4x, where we're looking at 75 to 300 or so.
I can understand why this is given that typically when we see actual distortion data, it increases quite rapidly below 2x Fs.
I have not seen distortion measurements for 'good domes'. Possibly this is because they are older and such measurements are a more modern take and easier to do.
Why is it OK to use a dome midrange with XO at Fs but not a cone?
You're right - I didn't notice that, just that there was a lead time from US stock. Well, now we know what the distributor costs are like. :-(
I don't have your answer, but fwiw, the Bliesma T74B has an Fs of 440 Hz, while the distortion data looks quite good down to almost 200 Hz. But since I haven't seen any builds with this driver yet I don't know how well it is really behaving in practice. I would agree if you were to say that most 3-way designs seek to put the lower crossover in the 150-300 Hz range (for a variety of different reasons), so a 440 Hz Fs seems to put the T74 (and other large domes?) in a kind of different use case. (linked to table at 6V input, worse at 8 V of course)
https://hificompass.com/en/speakers/measurements/bliesma/bliesma-m74b-6
Point is it’s not just a large dust cap on a small coil. So the dome over the coil acts as a mid and it has a low Xmas for transient resp. You have to give it listen forget just looking at the data
A cross border over at 300 is beneficial from some points of view, but doesn't mean that 400hz plus plus is bad. You can't find on type of middrange that beats all others in every parameter. Large midd dome is just one way to make a wonderful speaker. They can for example be plenty efficient, but have their limits in that regard. If you need more you just just choose something different.
Cheers!
Cheers!
All of us use cones down to their Fs! It's called bass driver ;-)
When yo have a look at the data I posted or from HiFiCompass - the 2x Fs "rule" simply isn't true. At least for modern drivers. Look at the THD of T25B and the resonance frequency - you kill the driver before it reaches 1% THD in the 2-4kHz range. And THD stays down even in the Fs area. Or B&C DE360 - completely different driver, also stays clean very close to the resonance frequency. M74 actually goes up in THD when you come in the Fs area, but over all THD is so incredible low ... it's still in the area of 2 High End 12".
You cross over a cone midrange at it's frequency cause it can't do more Xmax. Through the compareable heavy membrane Fs is low but it doesn't help, it's just what the spring/mass relation dictates.
Sorry guys for not being caught up on this thread. My health acted up a bit again and I'm having to prioritize being low on energy.
I'll try to look at everyone's posts soon and reply.
I'll try to look at everyone's posts soon and reply.
@IamJF Yes, cone drivers and others with a double suspension can deal with operating around Fs, just not much below it in conjunction with a ported or OB enclosure. Distortion goes up fast under Fs depending on suspension linearity.
The problem with CDs is their transient response and decay behavior compared to direct radiating mids. CDs have a greater tendency to overshoot in non linear ways around their multiple resonance modes. Its also very WG dependant. Direct radiating domes have tighter control not having all that coupled air to jerk around as CDs do.
The beauty of any driver which can be dissasembled is the opportunity to improve things like rear chamber dampening. Alot of mids have inaccessible, sealed rear cavities which don't allow for adapting rear dampening to the application intended. By far the biggest issue with CDs is overshoot and dampening close to their low end rolloff point. This is very audible and for me its the most offending audie behavior compared to most other problems in the FR. Being able to change dampening and rolloff can have big benefits. Sometimes you can gain something, but its usually minimal on higher end, well designed drivers.
The SS D7608 is one of those more affordable mid domes when considering price to performance ratio and the average cost of other decent 75mm+ domes which have better dome breakup performance.
As I've said before countless times turning blue in the face, the D7608 needs alot of care concerning back chamber dampening. The Qtc needs to be lowered down far enough to keep the moving mass from overshooting and losing control. Anything over 0.9 will cause problems even at reasonably lower HP freq and SPLs, raising 3rd order HD excessively. This behavior takes over quickly at higher SPL transients down low. This driver is by far the most sensitive mid I've used in terms of rear chamber construction.
Those who think the D7608 can be used with a first order HP filter and no back chamber (quasi OB) will be severely disappointed. Thats also because what comes out of the back of the motor isn't very linear or flattering. That vented motor has likely misguided many before having attempted to use it without a chamber, looking at most of the feedback people have given who already tried.
You can be experimental with various chamber configurations on the D7608, but not using one at all will yield very disappointing results. If you don't apply enough flow restriction right behind the motor, it will negatively impact resolution virtually across the otherwise entire useful midrange passband. It will sound alot like a big cone driver with high Fs / Qms and flimsy, low Mms cone pushed too low and hard... alot like the typical puny magnet guitar speaker (with very short VC and bad cone breakup) used in most low buck combo amps. You'd want breakup on those, but in moderation and good taste.
I've gotten ahold of some new Merino wool felt to try on the D7608. It looks promising and I'll hopefully have measurements soon. I've tried designing a 3D printed back chamber in the past, but haven't quite got it to perform as well as some other chamber designs.
The problem with CDs is their transient response and decay behavior compared to direct radiating mids. CDs have a greater tendency to overshoot in non linear ways around their multiple resonance modes. Its also very WG dependant. Direct radiating domes have tighter control not having all that coupled air to jerk around as CDs do.
The beauty of any driver which can be dissasembled is the opportunity to improve things like rear chamber dampening. Alot of mids have inaccessible, sealed rear cavities which don't allow for adapting rear dampening to the application intended. By far the biggest issue with CDs is overshoot and dampening close to their low end rolloff point. This is very audible and for me its the most offending audie behavior compared to most other problems in the FR. Being able to change dampening and rolloff can have big benefits. Sometimes you can gain something, but its usually minimal on higher end, well designed drivers.
The SS D7608 is one of those more affordable mid domes when considering price to performance ratio and the average cost of other decent 75mm+ domes which have better dome breakup performance.
As I've said before countless times turning blue in the face, the D7608 needs alot of care concerning back chamber dampening. The Qtc needs to be lowered down far enough to keep the moving mass from overshooting and losing control. Anything over 0.9 will cause problems even at reasonably lower HP freq and SPLs, raising 3rd order HD excessively. This behavior takes over quickly at higher SPL transients down low. This driver is by far the most sensitive mid I've used in terms of rear chamber construction.
Those who think the D7608 can be used with a first order HP filter and no back chamber (quasi OB) will be severely disappointed. Thats also because what comes out of the back of the motor isn't very linear or flattering. That vented motor has likely misguided many before having attempted to use it without a chamber, looking at most of the feedback people have given who already tried.
You can be experimental with various chamber configurations on the D7608, but not using one at all will yield very disappointing results. If you don't apply enough flow restriction right behind the motor, it will negatively impact resolution virtually across the otherwise entire useful midrange passband. It will sound alot like a big cone driver with high Fs / Qms and flimsy, low Mms cone pushed too low and hard... alot like the typical puny magnet guitar speaker (with very short VC and bad cone breakup) used in most low buck combo amps. You'd want breakup on those, but in moderation and good taste.
I've gotten ahold of some new Merino wool felt to try on the D7608. It looks promising and I'll hopefully have measurements soon. I've tried designing a 3D printed back chamber in the past, but haven't quite got it to perform as well as some other chamber designs.
Appears to be 'boxer' branded, only reference I could find was here, a 10cm dome
https://audio-database.com/BOXER/speaker/t2.html
https://mjq.co.uk/equipment/boxer-t5-monitoring-system-for-sale/
Boxer T5
https://audio-database.com/BOXER/speaker/t2.html
https://mjq.co.uk/equipment/boxer-t5-monitoring-system-for-sale/
Boxer T5
They sell these for 10k? The whole set? That's an absolute bargain I would say ...