UMIK-1 measurement mic

[captrajesh]

what we're really looking for is gas flow resistivity. The "gas" in this case is air, which is the medium that sound travels through.

I like your explanation, but I'm unsure about this.

I'm of the opinion that the sound is propagated across a medium by way of excitation of molecules. It would move even across different mediums by physical transfer of that energy.

The denser the material, the more difficult it is for air to travel through it.

ISTR once reading that water is a better conductor of sound than air.

AFAIK, denser the medium, quicker would be transfer of energy across the medium but higher would be the energy required to excite the molecules and thus dissipation would be higher. But hey, I'm talking out of my knowledge of High School physics. Would be glad to be proven wrong here at the cost of gaining some gyan.

 

[sdurani]

For the density of the material you have, exceeding 4 inch (100mm) thickness starts to make bass absorption less effective, so I wouldn't go any thicker than that.

The other aspect of absorption, as you mentioned earlier, is surface area. You can make good bass traps with the rockwool you already have. Build wooden frames that are 4 inches deep, put 100mm of rockwool in the frame, cover with speaker grill cloth, and straddle the frame across corners of the room.

This will give you a large surface area with a big air gap behind the trap. Will likely be more effective than super-chunck style corner traps.

 

[manoj.p]

I'm of the opinion that the sound is propagated across a medium by was of excitation of molecules. It would move even across different mediums by physical transfer of that energy.






AFAIK, denser the medium, quicker would be transfer of energy across the medium but higher would be the energy required to excite the molecules and thus losses would be higher. But hey, I'm talking out of my knowledge of High School physics. Would be glad to be proven wrong here at the cost of gaining some gyan.

Yes. But there is also one more angle. As the medium gets denser, the sound energy will stop going through it and rather start reflecting back. At that point, the denser material starts to behave like a solid material. If we want to absorb, the aim is to penetrate the material further and not reflect back. That's the reason for degrading performance of denser materials with higher thickness.

 

[john_k_antony]

For the density of the material you have, exceeding 4 inch (100mm) thickness starts to make bass absorption less effective, so I wouldn't go any thicker than that.

The other aspect of absorption, as you mentioned earlier, is surface area. You can make good bass traps with the rockwool you already have. Build wooden frames that are 4 inches deep, put 100mm of rockwool in the frame, cover with speaker grill cloth, and straddle the frame across corners of the room.

This will give you a large surface area with a big air gap behind the trap. Will likely be more effective than super-chunck style corner traps.

I have done exactly what Sanjay (sdurani) suggested. Mine is 6" thick though. I have filled the panels with 50mm Anutone Synth PF. Bass traps did help to reduce the unwanted boom, but for me the best results came with proper placement of my Subs and adding an additional Sub. It was Sanjay who helped me with in the past with all these great recommendations . Thank you very much buddy.

BTW, I have also got the UMIK-1, but I am waiting for my Emotiva replacement power supply board to come, to start the measurements.

Thanks,
John.

 

[sdurani]

I'm of the opinion that the sound is propagated across a medium by was of excitation of molecules. It would move even across different mediums by physical transfer of that energy.

AFAIK, denser the medium, quicker would be transfer of energy across the medium but higher would be the energy required to excite the molecules and thus losses would be higher. But hey, I'm talking out of my knowledge of High School physics. Would be glad to be proven wrong here at the cost of gaining some gyan.

Again, we're talking about acoustics in a home listening room, where sound is moving through the air.

I don't understand why folks are bringing up sound traveling through water. Did I miss a post where we switched topics to home theatre under the sea?

 

[captrajesh]

I don't understand why folks are bringing up sound traveling through water. Did I miss a post where we switched topics to home theatre under the sea?

The point I'm making is of sound propagation across different mediums; in this case between air and the rock wool and vice versa.

I'm not Thad but guessing that even he also would've meant the same.

 

[Santy]

What I would do is a 2 or 4" thick verical wall panel, as wide as the diagonal that you want and straddle the wall with with it. Its a simple, rectangular, tall panel to build and does the job very easily.

The other aspect of absorption, as you mentioned earlier, is surface area. You can make good bass traps with the rockwool you already have. Build wooden frames that are 4 inches deep, put 100mm of rockwool in the frame, cover with speaker grill cloth, and straddle the frame across corners of the room.

This will give you a large surface area with a big air gap behind the trap. Will likely be more effective than super-chunck style corner traps.

I have a similar setup now, two 2x4 ft panels of 2 inch glasswool. It did not help much in the lower bass range but ofcourse, it is too less coverage of corners. Now will work on 4 inch panels as tall as possible on all 4 corners.

My setup has changed much since this photo was taken, but it shows how the said panels are placed and the problem of insufficient space on the sides.

 

[sdurani]

I have a similar setup now, two 2x4 ft panels of 2 inch glasswool. It did not help much in the lower bass range but ofcourse, it is too less coverage of corners. Now will work on 4 inch panels as tall as possible on all 4 corners.

Yup, those panels are already at the right location. Just replace them and add the same to the back corners.

 

[Thad E Ginathom]

What does water have to do with a discussion of density and low frequency absorption? Is your home theatre underwater?

Again, we're talking about acoustics in a home listening room, where sound is moving through the air.

I don't understand why folks are bringing up sound traveling through water. Did I miss a post where we switched topics to home theatre under the sea?

Forget the water! It is just a flubble-bubledruble-bubbub-duble

<Wait!>

OK, drained the house...

Forget the water, it just an example of another material.



hyeah:

The point I'm making is of sound propagation across different mediums; in this case between air and the rock wool and vice versa.

I'm not Thad but guessing that even he also would've meant the same.

Exactly. Just because sound passes through air from speaker to ear, does not mean that it stays in air when it enters a "solid" material. eg it gets to the next room by making the brickwork vibrate, not just the airgaps.

Children prove that string conducts sound with tin-can telephone experiment.

I seem to have a knack of introducing irrelevancies --- even when I'm not actually trying to!

 

[captrajesh]

As the medium gets denser, the sound energy will stop going through it and rather start reflecting back. At that point, the denser material starts to behave like a solid material. If we want to absorb, the aim is to penetrate the material further and not reflect back. That's the reason for degrading performance of denser materials with higher thickness.

Hmm good point. Well said.

 

[Thad E Ginathom]

As the medium gets denser, the sound energy will stop going through it and rather start reflecting back

I've seen a diagram illustrating this very recently, but sadly I don't recall where. It was quite likely a link followed from HFV.

 

[Santy]

This is India Post

Usually this status (Custom Clearance) is updated once.
In this case, it is reflecting thrice. It is likely to be stuck there.

 

[Santy]

Got the delivery just now. :yahoo:

I am slapped with a duty of INR 3100. Don't know what calculation, but it is certainly high for USD 131 :sad:. But as long as these stuff are not detained, I am happy.

Incidentally the parcel came to Mumbai and after clearance, it was sent to Delhi by mistake and then it found its way back. That explains the same status seen thrice.

 

[Santy]

Finally got some time to unpack it.

That's my little daughter experimenting the box before I could....

Came in a nice plastic box. The supplied USB cable is fairly long. We can use an extension cable too.

Calibrated by Cross Spectrum Laboratories. Cal files were provided in a pen drive.

Mini tripod mic stand (supplied)

On a bigger tripod

Yet to configure / calibrate REW... Appears that I have to do lot of learning.

 

[ememm]

I am reading up on measurement microphones, and I stumbled on this thread. It was a very interesting read, but what happened finally? Where is the rest of the story?
Was Santy able to use it with REW? Was his LF problem fixed? Did the mic get passed around? What is his impression about the UMIK?

Waiting eagerly ....

 

[Santy]

I am reading up on measurement microphones, and I stumbled on this thread. It was a very interesting read, but what happened finally? Where is the rest of the story?
Was Santy able to use it with REW? Was his LF problem fixed? Did the mic get passed around? What is his impression about the UMIK?

Waiting eagerly ....

Thanks... I am also waiting for some free time to set it up.
The LF issues were taken care to a great extent after I installed some corner bass traps. So my desperation for calibration got watered down.

REW seems to have a steep learning curve, just as I feared. Or it could be only me who is stuck at a specific stage in the measurement process.

The official REW guide says, under SPL calibration section, that I must use an "SPL meter" and adjust the SPL figure on REW to match the reading on the SPL meter. This is where I got zapped. Does it mean I should buy an SPL meter also? I tried to use android SPL meter but I had difficulty in matching the levels.

Now that the thread is up I am looking for some expert help here.

How does MiniDSP UMIK-1 compares with Dayton UMM-6?

Is this all thats needed to measure any speakers, I mean be it HF or Mid or LF, so as to asses acoustic performance of an individual speaker?

Waterfall graphs, can they be measured using this same hardware?

I think both are equally good. However, cross spectrum lab mentions that UMM6 has relatively higher noise floor which means there could be some distortions in measuring quiet sources.

Yes this is all that would be needed, besides a PC (and probably an SPL meter too which I am not sure about) to do some great measurements. The advantage of getting a USB mic is that you dont need a phantom power supply or a sound card interface.

 

[sdurani]

The official REW guide says, under SPL calibration section, that I must use an "SPL meter" and adjust the SPL figure on REW to match the reading on the SPL meter. This is where I got zapped. Does it mean I should buy an SPL meter also?

The UMIK-1 should come with a calibration file that includes sensitivity, so REW will know how loud a sound is without you having to match its scale to a SPL meter.

 

[sound_cycle]

The LF issues were taken care to a great extent after I installed some corner bass traps. So my desperation for calibration got watered down.

I think I am in a similar state of mind.

I was convinced that that I needed DRC (and therefore followed this and related threads keenly) but stayed out only for cost. Okay that and lack of understanding too.

In the meanwhile I got rockwool panel room treatment, side, ceiling cloud etyadi. It all sounds good ***to me***.

I know it can be (much ?) better post measurement and DRC but (at least for now) I am happy with what the Dalis, positioning and treatment got me and enjoying my music.

Truth be told I think I have met *my* goals and expectations. Gadget lust and desire for hearing more may some day surface, who knows

ciao
gr

 

[keith_correa]

The official REW guide says, under SPL calibration section, that I must use an "SPL meter" and adjust the SPL figure on REW to match the reading on the SPL meter. This is where I got zapped. Does it mean I should buy an SPL meter also? I tried to use android SPL meter but I had difficulty in matching the levels.

Seems easy peasy.

 

[sound_cycle]

I was convinced that that I needed DRC (and therefore followed this and related threads keenly) but stayed out only for cost. Okay that and lack of understanding too.
<snip>Gadget lust and desire for hearing more may some day surface, who knows

And it does surface

After the rockwool, added a better PC, a better DAC and to my mind the what next is DRC

The LF issues were taken care to a great extent after I installed some corner bass traps. So my desperation for calibration got watered down.

REW seems to have a steep learning curve, just as I feared. Or it could be only me who is stuck at a specific stage in the measurement process.

Before I go pull the trigger on the umik and launch towards what seems to be a difficult task, thought i would ask you how your DSP experiment worked out ? how much impprovement/ difference ? and just how steep, is it for the fainthearted

ciao
gr