2019/09/19

MarkAudio "OM-MF519" Speaker assembly Part 7 - frequency characteristics

OM-MF519_DB_1.jpg

After painting, I played a lot of music with this speaker for sound aging.

My personal impression is that the bass sound is very loud despite the 8cm full range. This is probably due to the bass enhancement effect of the double bass reflex.

# frequency characteristics (distance 1m, Pink noise, measurement by RTA app "Audio Frequency Analyzer")
OM-MF519_DB_freq.png

However, looking at the frequency characteristics measurement above, it seems that the elasticity and tightness are retreating compared to a general bass reflex type, probably because 125-200Hz is slightly depressed. In a sense, 100Hz or less is too high.

Next, I adjusted the length of the second duct and examined how the frequency characteristics changed.

# Original duct (15cm)
duct-original.png

duct-original.jpg

I prepared a paper pipe with a slightly smaller diameter and measured it in units of 2cm.

The level of 100Hz decreased in the duct +2cm. It may be the effect that the duct area is slightly reduced.

# Duct +2cm
duct-2cm.png

duct-2cm.jpg

After that, the length of the duct was increased by 2cm, but no significant change was observed. It is also possible to pick up ambient noise.

# Duct +4cm
duct-4cm.png

duct-4cm.jpg

# Duct +6cm
duct-6cm.png

duct-6cm.jpg

# Duct +8cm
duct-8cm.png

duct-8cm.jpg

# Duct +10cm
duct-10cm.png

duct-10cm.jpg

# Duct +12cm
duct-12cm.png

duct-12cm.jpg

As a trial, I changed the length of the upper and lower ducts extremely. But, it did not be much different from closing the duct.

# Duct +2cm, +10cm
duct-10cm-2cm.png

duct-10cm-2cm.jpg

These results was not clear, so I have to try several times with different dates. I try listening with a duct length of + 4cm for a while.
posted by toons at 03:20 | Audio