Robh3606 said:
Hehe. Reminds of my first "proper" speaker project (i.e., measured and designed with Speaker Workshop). I took great care to equalise a strange bump in the woofer's response. Some time later I learnt about baffle step/edge diffraction....
fb said:
I've just ordered some TD15M apollo, and a TD18H - how safe is it to run these to Xsus?
🙂
One of my testing parameters was to try to break the suspension at full xmax, these are designed to be abused. They will audibly tell you when you have hit the suspension limit, and unless you add still another notch on the volume control it shouldn't hurt the driver.
tinitus said:I wouldnt rate AE woofers as pro woofers
Maybe pro studio woofers, in line with ATC, Altec etc
You could rate them as pro woofers in regards to the long term heat power handling. The main difference with pro drivers is the ability to play at loud levels with compressed music for hours upon hours without the coil burning up.
Sure
TD18H I would say is a pure PRO woofer
But not IB15 or the Dipoles
RCF have woofers with 3000watt rating, which seem to push the limits
Seems like the unofficial "new standard" for big woofers is 1000watt rating, minimum
But ofcourse using multiple woofers will change a lot
Danley even makes subs with small cheap Tangband woofers
TD18H I would say is a pure PRO woofer
But not IB15 or the Dipoles
RCF have woofers with 3000watt rating, which seem to push the limits
Seems like the unofficial "new standard" for big woofers is 1000watt rating, minimum
But ofcourse using multiple woofers will change a lot
Danley even makes subs with small cheap Tangband woofers
Dennis, you and Brandon beat me to a pulp over the past couple of years 😀
Thy did get my feet wet though by convincing me to dive head first and Im still happy with those results.
Now Im hooked and learning daily. Finished the loudspeaker design book but it will take a couple more reads to get it all to sink in.....Im sure by my 10th DIY build it will all actually click.
You should be filling in those questions with answers to help a dumb guy out 😉
In my earlier post, I didn't mean to discount measurements. Certainly the measurements and numbers are critically important. I merely meant that they are not everything, that we also need to use our ears for guides as well.
As to using professional drivers, I don't think there is any valid reason why many of them can't be used for home hi-fi. I saw someone mention earlier about using the Eminence 6" professional midrange and the Eminence APT50 horn tweeter. I like the idea and may eventually try them for my home setup. Haven't decided on which woofer yet..............I'll have to look at the numbers 😀 on a few of the affordable ones.
As to using professional drivers, I don't think there is any valid reason why many of them can't be used for home hi-fi. I saw someone mention earlier about using the Eminence 6" professional midrange and the Eminence APT50 horn tweeter. I like the idea and may eventually try them for my home setup. Haven't decided on which woofer yet..............I'll have to look at the numbers 😀 on a few of the affordable ones.
Andre Visser said:
F=force, M=mass, A=Acceleration (directly related to sound pressure level)
F=M*A, therefore A=F/M
A higher mass driver simply requires more force than a lower mass driver to achieve the desired acceleration (SPL). It doesn't necessarily have a poorer transient response.
Inductance is a much better quantifier for impulse response than mass
augerpro said:SPL is an acceleration?
I believe it is directly related to acceleration. For example, a 50hz tone and a 10khz tone reproduced at the same level (assuming equal surface area between drivers) will possess the same acceleration, but very different velocities.
augerpro said:
thadman said:
The precise statement is:
At low frequencies (wavelengths large compared to radiating surface) the pressure generated by the source is proportional to its volume acceleration.
Another way of stating that is that the radiation impedance seen by the driver looks like a mass at LF. However, outside of the LF assumption this isn't true. At HF the radiation impedance looks more like a resistor, so (on-axis) pressure is proportional to volume velocity instead of volume acceleration.
thadman said:
OK, my view, to get a stronger motor, you need a stronger magnetic field and a larger/heavier voicecoil, somewhere you should get an optimum point that will vary depending on intended use.
Most if not all of the driver and loudspeaker manufacturer will emphasize how much measurement AND listening hours went into the development of their products, why would they have those expensive high tech listening room for if it was not important.
Even though they know the system will not sound the same in your homes they still want to know what measurement matters the most, there is no other way I know of to check what effect the result of ANY measurement has on the sound but listening.
Even though they know the system will not sound the same in your homes they still want to know what measurement matters the most, there is no other way I know of to check what effect the result of ANY measurement has on the sound but listening.
There are many more pro drivers than home audio drivers that approach maximum conversion efficiency, which often translates into less energy available to support resonances and colorations, as well as having less thermal compression for a given SPL. Also, even if all the midband efficiency is not needed, it can be equalized out readily enough in the xover. My favorite is doing so with a high quality passive xover, because a little math shows how the voltage divider action will give some of the advantages of transconductance amplification through the mid band including even less thermal compression and the reduction of certain magnetic circuit eddy current, hysteresis and voice coil inductance nonlinearities.
So a well chosen 102db/w/m midband 15" driver could be equalized to 96db in a properly tuned BR alignment giving essentially flat real world response down to ~30hz with excellent thermal compression and driver resonance characteristics along with SPL capability and magnetic circuit performance that a 'hi fi' driver couldn't touch, especially if it was a remagnetized and reconed alnico type which is regarded as ultra boutique magnetic circuit technology on the new driver market nowadays.
So a well chosen 102db/w/m midband 15" driver could be equalized to 96db in a properly tuned BR alignment giving essentially flat real world response down to ~30hz with excellent thermal compression and driver resonance characteristics along with SPL capability and magnetic circuit performance that a 'hi fi' driver couldn't touch, especially if it was a remagnetized and reconed alnico type which is regarded as ultra boutique magnetic circuit technology on the new driver market nowadays.
Tom Danley said:
This is a very good analysis and I share this view.
My goal is to have very low distortion (because I simply hate it, ok? 🙂 ), therefore having extra headroom of 20+db plays to my favour.
When you look at distortion graphs, they are quite different from 80 to 90db. Go figure how they are at 110db.
I was telling a friend a couple days ago that my woofers dont move 1mm and they play loud. it's because they were developed to handle high power and high excursions.
Ehh, a woofer doesnt move less just because it has high sensitivity
How much a woofer moves is solely determined by music, size, SPL, and how deep it goes, determined by design, right?
In that respect the terms are the same for hifi and PRO woofers, apart from powerhandling
I have found that distortion at high SPL is largely determined by crossover design
Or should i say absense of acoustic anormalities
Large Xmax hifi subs that go really deep may be different, of which I dont know much
About PRO woofers, it seem to me like the usual woofers are going up in low end
In short, Fs is bit by bit being raised to reach the higher demands for high SPL without being overloaded, and maybe achieved with less drivers
At the same time we see more of the new breed of specialised expencive PRO subs coming, with larger Xmax and lower Fs
Though Im not sure whether the PRO speaker "people" wants anything of whats below below 30hz, which could be exstremely demanding
It also seems like the 15" woofers are used more like low midrange drivers
So their Fs have also been raised bit by bit
Its how it looks to me, I may be wrong though
How much a woofer moves is solely determined by music, size, SPL, and how deep it goes, determined by design, right?
In that respect the terms are the same for hifi and PRO woofers, apart from powerhandling
I have found that distortion at high SPL is largely determined by crossover design
Or should i say absense of acoustic anormalities
Large Xmax hifi subs that go really deep may be different, of which I dont know much
About PRO woofers, it seem to me like the usual woofers are going up in low end
In short, Fs is bit by bit being raised to reach the higher demands for high SPL without being overloaded, and maybe achieved with less drivers
At the same time we see more of the new breed of specialised expencive PRO subs coming, with larger Xmax and lower Fs
Though Im not sure whether the PRO speaker "people" wants anything of whats below below 30hz, which could be exstremely demanding
It also seems like the 15" woofers are used more like low midrange drivers
So their Fs have also been raised bit by bit
Its how it looks to me, I may be wrong though
tinitus said:
You are correct about size determining the required excursion for a given output level at a given frequency, but it seems that pro drivers tend to be larger than their hifi counterparts for a given bandwidth. I believe that is general perception of lower excursion comes from.
As you noted yourself, often pro drivers in the 10"-15" range are used for midrange duty that would typically be the role of a substantially smaller hifi lineup. At least, that's what I've generally seen.
Some drivers fit in between eg the old Audax Pro series drivers I have a pair of the 2040 10 inch bass units and 215 horn loaded soft domes.I doubt if anyone would use them in a PA system but they are usefull for domestic useage.
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