This is fascinating. If you were talking about this solution all the time, I didn't get it at all. This is ingenious.
Could you show just the windowed-IR responses, without the FDW? It seems pretty usable (with an active EQ).
How low do you think it can be used in a home setup? A single 4554 can be used down to ~600 Hz, so I would expect you should be able to get lower with this (to me, this would be the reason why to do it in the first place). The LF response alone doesn't seem very extended though - the midrange section is obviously not as much "horn loaded" here. It would be interesting to compare it when used with a regular 1.4" adapter.
Could you show just the windowed-IR responses, without the FDW? It seems pretty usable (with an active EQ).
How low do you think it can be used in a home setup? A single 4554 can be used down to ~600 Hz, so I would expect you should be able to get lower with this (to me, this would be the reason why to do it in the first place). The LF response alone doesn't seem very extended though - the midrange section is obviously not as much "horn loaded" here. It would be interesting to compare it when used with a regular 1.4" adapter.
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But maybe I still don't get it. What we're looking at here? - Are these the MEH entrances of the midrange into the horn or not?
Hi Marcel
well it was one of the approaches I was talking about 🤣. Sometimes it is difficult to explain an idea without drawings/pictures.
I have a second unmodded dcx. I will buy the standard 1.4 adapter and test against it. Also I will compare the bms on the same horn.
Regarding LF extension: I am not so happy with the result. But I am not sure if maybe 520mm horn would have been better in this regard????
You want windowed IR or spl? Can do this later...
well it was one of the approaches I was talking about 🤣. Sometimes it is difficult to explain an idea without drawings/pictures.
I have a second unmodded dcx. I will buy the standard 1.4 adapter and test against it. Also I will compare the bms on the same horn.
Regarding LF extension: I am not so happy with the result. But I am not sure if maybe 520mm horn would have been better in this regard????
You want windowed IR or spl? Can do this later...
This shows my printed insert IN the dcx. The original thorn is kept and this adapter modifies the outer geometry to fit your stuff. It morphes the cross section area according to your bms adapter. The ports you see here are the LF entrance ports in the dcx around 5mm away from the HF diaphragm.
The black thing is the insert. Between thorn and outer wall of the original driver. Understood? Not at home can do more pics later...
No. In this pic:
Top: back side of driver
Bottom: horn outlet
No 180* turn like on the bms. Diaphragm exit shows towards horn
Top: back side of driver
Bottom: horn outlet
No 180* turn like on the bms. Diaphragm exit shows towards horn
OK, now I get it! Thanks.
Then I would perhaps expect a better LF extension. Using A520G2 could add a few dB due to a bit narrower beamwidth below ~600 Hz, don't expect big difference.
Then I would perhaps expect a better LF extension. Using A520G2 could add a few dB due to a bit narrower beamwidth below ~600 Hz, don't expect big difference.
Originally the cross section area after the ports was much bigger. Maybe this is an issue for LF. I will compare later with my 520 Gen1 measurements I did some time ago.
As requested by Marcel the windowed responses without FDW. We measured with the mic in front of a acoustic foam. It reflected more than expected....so please ignore the constant waviness. No smoothing; only gated 12ms.
I tried the throat mic probe today, just a quick excercise to see what it does.
red = far-field response (4.5 ms)
blue = probe response (4.5 ms)
black = probe response (20 ms)
(red/blue levels are arbitrary)
I sure plan to spend more time with this (and will probably get rid of the needle to avoid a compensation),
but from the data I already have for the A460G2/4554, it seems to me that there's not much of early reflected sound from the mouth. At least I would think it would look differently. What's apparent though, is that the short 4.5 ms window is too short to fully describe the main resonance and I assume that this is the same for the far-field data. We really need to measure these devices in larger reflection-free spaces. Also the EQ must be done much more carefully to really compensate this resonance in its true shape.
- This is the raw IR at the mic probe position (in the wall roughly 20 mm in front of the driver front face):
red = far-field response (4.5 ms)
blue = probe response (4.5 ms)
black = probe response (20 ms)
(red/blue levels are arbitrary)
I sure plan to spend more time with this (and will probably get rid of the needle to avoid a compensation),
but from the data I already have for the A460G2/4554, it seems to me that there's not much of early reflected sound from the mouth. At least I would think it would look differently. What's apparent though, is that the short 4.5 ms window is too short to fully describe the main resonance and I assume that this is the same for the far-field data. We really need to measure these devices in larger reflection-free spaces. Also the EQ must be done much more carefully to really compensate this resonance in its true shape.
- This is the raw IR at the mic probe position (in the wall roughly 20 mm in front of the driver front face):
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Here the black curve is the FR measured ~10cm from the mouth, 16 ms gate (red = 4.5 ms).
And it doesn't change further with a longer window, this is for 25 ms (blue):
And it doesn't change further with a longer window, this is for 25 ms (blue):
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Even more difficult than a good measuring technique is to know what one's actually searching for. For example on this scale, are we even trying to find the small wiggles from the far-field measurement?
The probe measures pressure at a single point. What if the wiggles only build up in a field? Just within the bandwidth of the wiggles is the biggest sound pressure, maybe it's "too much".
But iff it does not result in distortion, we shouldn't be bothered. Maybe this is asking too much, leave it to future generations 😎
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The probe measures pressure at a single point. What if the wiggles only build up in a field? Just within the bandwidth of the wiggles is the biggest sound pressure, maybe it's "too much".
But iff it does not result in distortion, we shouldn't be bothered. Maybe this is asking too much, leave it to future generations 😎
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Reveals a strong mode at ~ 620 Hz
The idea is to measure all the three G2 bodies I have at hand and search for possible differences that would correlate with the far-field differences. If there won't be any noticeable differences, the far-field differences will be just mouth related.
Sure, that's the fundamental resonance of the added throat extension.
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I don't know how all of your 3D printed devices sound when you just hande them, all of mine have crazy loud resonances, easy to trigger with any vibration anywhere in the structure like handling them in your hands.
I haven't ever seen such graph mabat just posted, the throat mic, so I speculate the frequency response peaks ~600, ~1600, ~5kHz, 8.5kHz ... are structural resonances.
I haven't ever seen such graph mabat just posted, the throat mic, so I speculate the frequency response peaks ~600, ~1600, ~5kHz, 8.5kHz ... are structural resonances.
I'm pretty sure that those are mostly resonances of the needle probe. I guess I need to print a special adapter with a mic directly in the wall. Anyway, it should be possible to compensate for this.
I should have mentioned that the FRs measured anywhere outside the horn were taken with my regular mic, not the needle probe.