Dear friends,
During the past decade I collected a lot of loudspeaker drivers, some of them for my particular projects, some just to feed my curiosity.
I made duly measurements for all of them which I decided to share in a dedicated web page as well as some of my loudspeaker system projects.
I am starting with eight-inch fullrange drivers, some of them measured in a specially constructed "Universal" Horn.
I hope this information will be useful for many audio DIY-ers.
Here it is:
Loudspeaker Raw Driver Measurements
I've started with the followed drivers:
Coral Beta 8
Fostex FE-208 Sigma
Fostex FP-203
Lorenz S-888
Pioneer PIM-8L
Tang Band W8-1772
More measurements will come soon...
Any comments and suggestions are welcome!
During the past decade I collected a lot of loudspeaker drivers, some of them for my particular projects, some just to feed my curiosity.
I made duly measurements for all of them which I decided to share in a dedicated web page as well as some of my loudspeaker system projects.
I am starting with eight-inch fullrange drivers, some of them measured in a specially constructed "Universal" Horn.
I hope this information will be useful for many audio DIY-ers.
Here it is:
Loudspeaker Raw Driver Measurements
I've started with the followed drivers:
Coral Beta 8
Fostex FE-208 Sigma
Fostex FP-203
Lorenz S-888
Pioneer PIM-8L
Tang Band W8-1772
More measurements will come soon...
Any comments and suggestions are welcome!
... Rutcho very beautiful and interesting website thanks for sharing here.
WOW, look at Lorenz S-888 nice response ! Why there are no 8" full range driver nice as that available today ?
Opposite, Coral Beta 8 looks terrible, yuck !
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Bob Brines as general observation good argument warts accepted, though with technical eyes they ain't pretty.
Looking particular these two plots it looks like tweaking red blu or green axis on Lorenz S-888 that the more uniformity will do that other two axis will benefit too a certain level, maybe this is some of what Elias like.
At Coral Beta 8 red blue and green axis looks more like three different drivers measured and that tweaking response of one of the axis never will benefit the two others. If having visitors in listening room some will have their seat in the red axis.
Looking particular these two plots it looks like tweaking red blu or green axis on Lorenz S-888 that the more uniformity will do that other two axis will benefit too a certain level, maybe this is some of what Elias like.
At Coral Beta 8 red blue and green axis looks more like three different drivers measured and that tweaking response of one of the axis never will benefit the two others. If having visitors in listening room some will have their seat in the red axis.
I enjoy full rangers warts and all. I used to get hung up on FR charts but not anymore. I just find the drivers I like, toe them in how I like and enjoy. Some are bright others dull but IMO they do more right with the music than multi way systems. I think it depends on how and what you listen for.
Although I publish crossover networks for some drives I do prefer the unfiltered sound of the full ranges too.
Here are some updates:
University Diffusicone Eight
Tang Band W8-1808
It's meaningless how the magnitude response looks like at a specific angle. We listen to speakers in rooms and with two ears mounted in a movable head some inches apart.
Important is how the response changes within the listening window and how the power response affects the spectrum of the indirect sound field within a specific listening room.
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Thanks a lot for these! It shows that price and performance are only loosely related
How did you measure (mic distance, gating time, etc.)?
Did you also measure other angles? It would be highly interesting to have measurements in 5° steps within the listening window and 10° for all other angles.
WOW, look at Lorenz S-888 nice response ! Why there are no 8" full range driver nice as that available today ?
I agree. Exactly what I'm looking for. I don't know any current 8" full range driver with such great off-axis frequency response.
Time to start a Kickstarter project to bring back that design?
The SPL and BD measurements were made at 1m distance.
The time window is 4 ms.
The measurement room is acoustically treated, but this is not an anechoic chamber, so the correct measurements start from 250Hz.
The THD measurements were made at 25cm distance.
Unfortunately I don't have a measurement turntable, that's why it will take a lot of time to make full off-axis diagram and I am afraid it won't be accurate enough.
I think you will find the trebles of the S-888 a bit muted even on axis. If you want a wide listening window I recommend a supertweeter.
Thanks.
I have markers on the floor and turn by hand. It's good enough. The important information is how much the response changes with angle. Some drivers change a lot some don't. Only lots of snapshots will reveal such behavior.
I wouldn't use any full range driver without EQ anyway. It's easy and inexpensive to do these days.
The 888 seems to have a rather smooth off axis behavior so equalization will most likely improve the overall response not only for a certain angle but for all angles. Most other full range driver don't behave that way.
Yes it would be interesting to find out the method to achieve similar performance.
I think the whizzer cone design may be the key here.
As rutcho says:
"...bright red color of its whizzer cone which is due to the substance with which it has been soaked for more rigidness."
Now, how rigid really is the whizzer ?
Approach could be, take a cheap 8" full range with whizzer, perform a technique to increase rigidness of the whizzer, measure if off axis response has improved.
Possible test bed: Visaton BG20
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But maybe this driver is cheating a bit since it's a sort of 'coaxial' 
Alternative Monacor SP-200X though cost/Xmax points to BG20.
More arrow up regarding Lorenz S-888, at rutcho website in the brochure pdf file published in High Fidelity Magazine 1959 it says "For stereo or monoaural - singly or in matched pairs" that's good old days though doesn't say if it's the sound parameter that are matched but then probably the colour of whizzer cone
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