The no offset with measurement at woofer axis is correct. Nice right triangle no pre-ring because the “offset” is provided by fact that tweeter is below woofer so the delay is built into the triangle.
If you offset the tweeter, mic needs to be on tweeter axis. The prering you see is the woofer arriving early because of too much delay.
If you physically offset the tweeter then it needs to go on top of the woofer. Another way is to have a waveguide with 2.4in offset. This will improve polar dispersion as well as preventing diffraction from the hard edge at the step.
But whatever sounds best to your ears is fine. But technically, this is the correct transient perfect response:
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The speaker already sounds kind of coherent/ smooth without the offset, already without the offset it is a good speaker to my ears. But when I read that XRK mentioned, that there should be about 3in delay to the Scan Speak - correctly speaking - , I thought I really have to do that and try it out. Outdoors without any (almost any) reflections you really kind of dramatically hear the difference. Without offset there is a smearing and limit of transparency, with the offset it sounds on the spot, perfect like 3D of the recorded space (classical music and Jazz). I had one friend who described it as "the overtones gear into each other/ intertwine". I like that expression, I imagine that the two drivers really go hand in hand over the more the less broad bandwidth they both play.
With all the reflections indoors the difference is not THAT big to hear (still big), when you go outdoors it is not very hard to find the very point/ sweet spot.
With the offset the heights more sound like a real tweeter, they are sparkling. Still I miss the tweeter, as some qualities of a tweeter still are missing (I cannot name them), but the resolution is quite impressive though. That goes hand in hand with my friend's description.
Still I am very surprised, that that what the ears tell you, does not go hand in hand with the measurements, which are worse with the offset. I am wondering if anybody could explain this to me.
I have to say, that I have an idea, and this is, that (as more energy is in the bass) - without offset the drivers are perhaps more synchronal in the bass and it therefor measures better, but the "overtones"/ heights are not coherent. With the delay the mids and heights are perfect, but the bass is not (?). Oudoors you can only judge the mids and heights, you hardly hear bass (due to the relatively small driver and the missing reflections). - I do not understand a lot of measurements and filtering/ crossovers (phase shift,...) and the knowledge one needed to explain what I have experienced, but this is a creative idea (...). Still one has to accept, that my offset measures worse.
With all the reflections indoors the difference is not THAT big to hear (still big), when you go outdoors it is not very hard to find the very point/ sweet spot.
With the offset the heights more sound like a real tweeter, they are sparkling. Still I miss the tweeter, as some qualities of a tweeter still are missing (I cannot name them), but the resolution is quite impressive though. That goes hand in hand with my friend's description.
Still I am very surprised, that that what the ears tell you, does not go hand in hand with the measurements, which are worse with the offset. I am wondering if anybody could explain this to me.
I have to say, that I have an idea, and this is, that (as more energy is in the bass) - without offset the drivers are perhaps more synchronal in the bass and it therefor measures better, but the "overtones"/ heights are not coherent. With the delay the mids and heights are perfect, but the bass is not (?). Oudoors you can only judge the mids and heights, you hardly hear bass (due to the relatively small driver and the missing reflections). - I do not understand a lot of measurements and filtering/ crossovers (phase shift,...) and the knowledge one needed to explain what I have experienced, but this is a creative idea (...). Still one has to accept, that my offset measures worse.
XRK:
Why? With what aim?
What I did is, that I measured and listened between woofer and tweeter center, in order to be independent of the distance, in order to be really able to judge the offset settings, and as it makes somehow also sense/ is not stupid, when you have the speaker right in front of you/ in the middle in front of you.
XRK, please, you should really try the thing with the offset...! Perhaps this thread will take an interesting direction then. It really does sound better, at least this is what I have experienced.
Why? With what aim?
What I did is, that I measured and listened between woofer and tweeter center, in order to be independent of the distance, in order to be really able to judge the offset settings, and as it makes somehow also sense/ is not stupid, when you have the speaker right in front of you/ in the middle in front of you.
XRK, please, you should really try the thing with the offset...! Perhaps this thread will take an interesting direction then. It really does sound better, at least this is what I have experienced.
If you offset AND listen on axis with the woofer, you lose the transient perfect that X mentioned, and you go too far to the other side.
That's what you can see in the results not being as smooth as the way X designed it.
If you offset the drivers, then you don't need to put your ears at the woofer level, so you can just flip up the speaker to have the FR on top, ear level... then you'll get the nice smooth Step, and might find it a tad brighter as well, since you will be on axis with the FR and less drop in the HF.
That's what you can see in the results not being as smooth as the way X designed it.
If you offset the drivers, then you don't need to put your ears at the woofer level, so you can just flip up the speaker to have the FR on top, ear level... then you'll get the nice smooth Step, and might find it a tad brighter as well, since you will be on axis with the FR and less drop in the HF.
I did not listen on woofer axis with offset.
6,1cm offset was listened to and measured in between the centers of the drivers. No offset = flat baffle was listened to and measured on woofer axis, and furthermore at an angle of about 45° on the woofer side, in order to get the same delay as if with the offset. Offset and this 45° setup measured similar, not transient perfect but sounding right.
6,1cm offset was listened to and measured in between the centers of the drivers. No offset = flat baffle was listened to and measured on woofer axis, and furthermore at an angle of about 45° on the woofer side, in order to get the same delay as if with the offset. Offset and this 45° setup measured similar, not transient perfect but sounding right.
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This driver is a good deal, but then I'd have to make a router jig to flush it......I'll just get the standard basket. Much easier
Correct on the measurements: electrically, it's the same driver.
Transmission Line Options.
I recently purchased 10 RS 225's for various projects.
1 pair used in 32 litre vented for MarkK's RS225/RS28 speaker
1 pair used in the Finalist t-line variant designed by Paul K
1 pair to be used in a set of new Travelers - will use the same setup as the Finalist
1 pair TBD (plenty of options available!)
1 pair for this 10F/8424 FAST system
I designed a T-line in hornresp with the following
system volume 43.37 litres
total line length 159.3com
S1 = 497 cm2
S2 = 375 cm2
S3 = 39 cm2
first segment is 58.4cm (driver offset)
second is 100.9 cm long
total length is 159.3cm or 62.7 inches
models very nicely
F3 about 28hz
I analyzed xrk's t-line posted a few pages and for me it is a bit too big
approx 229cm long or 90.1 inches
it is about 70 litres system volume (43 litres is better IMO)
F3 is about 25hz, a little more prone to excess cone movement
I have all the parts for this system but I am trying to get a little CNC done so as to have a 2.4" offset in a pretty cool fashion.
Will keep you posted once things start actually getting built.
I recently purchased 10 RS 225's for various projects.
1 pair used in 32 litre vented for MarkK's RS225/RS28 speaker
1 pair used in the Finalist t-line variant designed by Paul K
1 pair to be used in a set of new Travelers - will use the same setup as the Finalist
1 pair TBD (plenty of options available!)
1 pair for this 10F/8424 FAST system
I designed a T-line in hornresp with the following
system volume 43.37 litres
total line length 159.3com
S1 = 497 cm2
S2 = 375 cm2
S3 = 39 cm2
first segment is 58.4cm (driver offset)
second is 100.9 cm long
total length is 159.3cm or 62.7 inches
models very nicely
F3 about 28hz
I analyzed xrk's t-line posted a few pages and for me it is a bit too big
approx 229cm long or 90.1 inches
it is about 70 litres system volume (43 litres is better IMO)
F3 is about 25hz, a little more prone to excess cone movement
I have all the parts for this system but I am trying to get a little CNC done so as to have a 2.4" offset in a pretty cool fashion.
Will keep you posted once things start actually getting built.
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Hi OntarioMax,
Can you please show your TL simulation plots? I was trying to make it smaller but it did not have the flat extension I was looking for. A 43L version would be a good large standmount / or a floorstander with legs to get it up higher at ear level. How did you eventually fold it and where does the vent come out?
Cheers,
X
Can you please show your TL simulation plots? I was trying to make it smaller but it did not have the flat extension I was looking for. A 43L version would be a good large standmount / or a floorstander with legs to get it up higher at ear level. How did you eventually fold it and where does the vent come out?
Cheers,
X
This driver is a good deal, but then I'd have to make a router jig to flush it......I'll just get the standard basket. Much easier
Correct on the measurements: electrically, it's the same driver.
The 10F/8414 is also very close, round bezel and $70.
That's the one. I bought a pair and I waited too long to return them - seller had a 14 day return policy.