Idea to use Noise Cancellation to hear 1st crack better

Can someone try my idea to hear 1st crack better? I’m not ready to roast for a week or two.
You need: Android Device and Active Noise Cancellation headphones (I have a set of those made by Bose).
Using an android device, install “Sound Amplifier” (made by google, no ads).

Put the android device right next to the bullet with the app working. Listen through the headphones, and adjust the app settings. I think this should greatly reduce the Bullet’s fan and the exhaust fan noise.


Very interesting. This is a cool idea. I have an iPhone, but I will look for a similar type of app and perhaps try this out. I like the concept; I am assuming the app you refer to actively cancels white noise on its own (I was lazy and did not carefully read the entire description). If that is the case, the combo of that and Bose headphones should make the cracks very obvious.

I guess I should mention, though, that first crack has been very easy to hear on the Bullet compared to the gene cafe I used for the last 14 years. So this seems like a mostly academic exercise (albeit super fun).

Yeah, the app does active noise cancellation, and plays it through the headphone port. Google had it listed under the accessibility section to help people with hearing trouble. Maybe iPhone has something similar. Later I saw people were looking at bird song identification apps, but I think those only record, not play live.

1C has been very difficult compared to the Behmor 1600+ I was using before.


Very interesting. I’ve been using a medical stethoscope with the membrane removed, placed over the bean chute. This seems more convenient and comfortable. No stethoscope earpieces jammed into your ears!

Are your headphones bluetooth or plugged into your phone? Also, how do you know which noises to reduce or eliminate?

I tried this out today. The Bose ANC headphones (wired, not bluetooth since someone asked) were great through preheating, and up to about 1C. The Sound Amplifier app brought back a lot of the fan noise, and I couldn’t narrow in on the cracking noise. I’m going to try another app.

They were wired. The Sound Amplifier app was pretty bad. I’m going to try another app. I saw some people talking about apps designed for listening to bird calls.

Good approach since it maintains exhaust fan flow.


Interesting info! Have you tried placing the stethoscope elsewhere? Does it work on the glass window at all? I’m on the fence of buying one and curious to know if we can pickup 1C without having to remove the bean chute cover or the tryer.

I’ve been using Airpods Max while roasting (no software or music playing, just have them on my ears in noise-cancelling mode). This helps me hear the cracks much better over the noise of my vent hood. Probably any noise cancelling headphones would work similarly.


I will have to try this with my Airpod Pros this week when I roast. Great idea!

I whole heartedly agree with this. 1C and 2C was easy to hear on my Behmor 1600. The Bullet is a little more challenging. Overall, I’m liking the Bullet better than the Behmor, though.


Hello! How’d it go with the AirPods Pros?

All that thermal mass has a price! :slight_smile:

It’s a good idea… I have active noise cancelling headphones, I’ll try those out on the next roast.

I’ve also noticed that batches larger than about 400g are significantly easier to hear the cracks for. (Though I do wonder if I’m hearing the start, or just a larger first peak)

It’s probably good for my hearing to wear something that minimizes the noise, even if it doesn’t make it any easier to hear 1C!

Here’s a simple homemade stethoscope that has been working quite well for me;

Wire hanger with the hook removed, fish tank silicone tubing, tape, spare earbuds and a little funnel.

Close up of the funnel

Close up of the earbud (attached to the tube)

Hope this helps, cheers!

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Old thread but where on the bullet do you place the funnel?

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Place the funnel either over the tryer (with the tryer removed) or remove the rubber cover and use the bean chute. Opening the bean chute affects airflow thru the exhaust fan since that fan creates a low pressure to draw air thru the drum, so it’s probably best to alternate between listening and covering.


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As @bab mentioned or just on the glass part.

After using the bullet for a while I have started to clearly hear/recognize the first crack and no longer need the “device” so I’m glad I McGuyvered one instead of purchasing :smiley:

Hope it helps, Cheers!

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