Saturday, August 5, 2017


Been busy between school and work, but that goes without saying, doesn't it? Working part time and covering (at least summarily) thermodynamics, geometric optics, special relativity, and quantum mechanics in five weeks will do that.

Anyway, recently I've been having fun looking at flashlights so I figured I'd post some of my findings and interests here.
This will basically be a short list of  my favourite lights and comments for my future reference as well as anyone that finds it useful.

Listing roughly from least to most powerful, but don't skip directly to the end of the list, each of these has it's own niche.

160 lumen water resistant USB rechargeable keychain light. ~$40. Point of interest is primarily the option of white, red or UV light from one light. Most other multi-output lights are much larger

240 lumen USB rechargeable keychain light. ~$35. High CRI is the main attraction here, as well as decent output. If higher output is more important than colour rendering, there is a non-CRI version as well ($30). I personally prefer the versions before 2017, but the base functionality remains.

Convoy S2(+)

This light is available in a number of different configurations. If you have any interest in customizing your light, this is a good place to start. (Too many varieties to link, but I got mine from
Basic 18650 tube light, typical max 395-853 lumens, depending on driver configuration.
Primary attractions for this light are its low price (Usually approx. $20) with decent quality and customizability. The warm tint options and price are the things I really like about this light. 
Not waterproof, but somewhat water resistant. What do I mean by that? I mean that when put in water, it fills up with water but keeps working.

Nitecore P12/MH12
Lumping these together because they're essentially the same flashlight with or without USB charging.
1000 lumen 18650 tube light. 4 modes + disco modes (strobe, SOS, beacon)
There's not really that much to say about these, they're nice lights that do a good job. One thing I do appreciate about my MH12 is the thermal regulation and heatsinking.. I can set it to high and not worry about it burning me if I touch it. I can even wrap my hand around the head even after it has been on a significant amount of time without discomfort.
The MH12 has USB recharging built into the flashlight, but with reduced waterproofing.
MH12 ($85)        P12 ($60)

The next two models are listed in order more by continuous output than peak.

Emisar D14 Quad
(Image from

This is a neat little hotrod light. 3000-4000 lumens peak, with some selection of  Nichia or Cree LED's, as well as multiple finishes. I think the most notable feature on this light is its custom open source firmware, and the most innovative feature of that software being the configurable thermal ceiling. The ramping brightness is nice too. ($40)

Manker E14 II
This is fairly similar to the previous light, but with USB charging. Other points of difference are the firmware (which is pretty good, but without thermal configuration or battery check) and slightly lower peak output. These lights are really neat, but generate a lot of heat and step down to approx. 1000 lumen range after about 30-60 seconds. ($65)

Convoy C8. 

There are enough models that I'm not going to link to any particular models. Approx. 1000 lumens, 1x18650. Cheap but decent light with lots of throw. Can be configured with warm or cold tint LED's or anywhere in between. ($20)

{Nitecore EC models}
These have dual batteries, so good runtime, and a one-piece body for good thermal dissipation.
There are various models here as well, so no link. ($50-$150)

This flashlight looks to be a very handy multipurpose light when something a little larger is an option. White, red, green, blue, and UV in one light.
Dual 18650 design, still a handy size. Approx. 2000 lumens (white)

(Different enough I figured I'd give them their own section)

Wowtac A2/A2S
If you need a cheap headlamp that's actually probably pretty good, look here. For the price of the dim plastic ones you can get at Home Depot you can actually get a right angle metal light with a USB rechargeable 18650 battery. 550 lumens for the A2, and about double that for the A2S
A2 ($20)        A2S ($30)

1000 lumen headlamp a cut above the wowtac. The primary attraction for me is the warm tint option.
Approx. $55.

End notes, I am not affiliated in any way with anything mentioned above other than that I own some of these lights and have ordered from some of these companies.

Monday, January 18, 2016


While on break I've been tweaking my sound system, and while looking for RTA software came across REW. REW is a pretty awesome piece of software, it runs on windows, mac, and Linux and it's free!

My PA speakers are pretty good, but do need a fair bit of EQ. I've been tweaking by ear, and got decent results, but it was also rather subjective, and time consuming. With REW I can run a frequency sweep in a couple of seconds and get a frequency response graph, and the parametric filters needed to correct it to the target frequency response! Alternatively you can use the generator tool to play pink noise through the system and adjust your equalizer until the RTA shows flat. I usually use the second method because I have a nice 31 band EQ, but my main system processor only has 5 PEQ filters. I do have a separate PEQ with something like 20 filters, but it's Behringer and has had some reliability issues, so I try not to use it.

Red is the raw speaker response, green is after correction. I should add, this is indoors in a room comprised almost entirely of hard reflective surfaces, and these are PA speakers, so the graph above is quite decent. Above is with 1/3 octave smoothing, below is the raw measurement:

There's another cool smoothing option called var smoothing which I really like. See below:

Anyway, enough distractions. Moving on.
Here's an example of the auto EQ feature:

The red trace at the top is the measured frequency response, below is the corrected (predicted) frequency response. Blue filled above are the filters needed to correct the response.

Not bad, except for that weird dip around 125, but some of that is due to mic and speaker placement too, when I was moving around it came and went to a degree. Here's an example of the format for the exact filter requirements:

Equipment: I don't have a dedicated measurement microphone, so I thought I'd try using my H4N and its built-in microphones. I measured, and corrected, and it did not sound right. Muted and muffled. I realized I should probably check how flat the frequency response on the H4N mics, and while not terrible, there's enough to make a significant difference.

So I don't have a calibrated mic, but I do have it's frequency response, and REW accepts calibration files, so if I can figure out the calibration file format I could hypothetically make my own calibration file for the H4N! So I looked up the file format, and it's pretty straightforward, arbitrary frequencies, space(s) or tab(s), and dB from reference. Eyeballing the chart, this is what I came up with:

"Sens Factor =-??dB, SERIAL NO: 0021####"
Calibration file for Zoom H4N
Calibration points are eyeballed from the 
manufacturer's provided frequency response chart.
10 -6
30 -3
40 -2
50 0
60 0.75
70 1
80 1.5
90 1.5
100 2
200 2.5
300 2.5
400 2.25
500 2
600 2
700 2
800 2
900 2
1000 1.5
1500 0
2000 2
2500 3.5
3000 3.5
4000 6.5
5000 4.5
6000 6
6500 6.5
7000 6
8000 5
9000 2.5
10000 2
12500 4.5
15000 4.5
17500 6.5
20000 -2.5

Which gives the graph below.

Not perfect, but within a few dB, and now calibration sounds great. This was a good learning experience, and now my system sounds great :)

I do enough sound work I figured it would be worth it, and I had a gift card, so I went ahead and got a real calibrated measurement mic. Dayton EMM-6. Came with a hardshell case, clip, and windscreen.
Not bad for $40, and it's been doing a pretty good job.

Tuesday, November 10, 2015

Sound and moon

My blog appears to be just about dead, but I'm keeping it hanging on every once in a while. I'd like to post more, but college and work are keeping me really busy.

Anyway, just ran across this, and thought it was a pretty good demonstration of a speaker for those curious.

Also, combo post! Here's a photo I took of the moon eclipse a while back.

Monday, June 29, 2015


I know I haven't posted here in quite a while...

Here's a visual representation of compression. This can be applied to audio too.

View full size!

Raw source (not really, but close enough)

Dynamic range compressed. Blacks flattened, loss of detail.

Data compression. This is why I don't like listening to MP3's in general.

Wednesday, May 20, 2015

Speaker progress - Almost done!

Almost done!

My little sister wanted to draw...

Prepped to paint

The finish actually looks pretty good for just unprimed plywood and spraypaint.

Inside done!
Sounds good too.
Trust me, it looks better in person.

Tuesday, May 12, 2015


Here are things that I find interesting or helpful, or both: 

     Blender is a free, full-featured, open source 3D suite. It has some amazing tools, and with a little work, you can make some pretty neat things. (
    Ninite is a great website if you want to do a batch install of a selection of common programs.
    Sadly it only works on Windows now.
    Grooveshark is a great free music streaming site with good variety and quality.
Stay away from their HTML5 version though. Last I checked it was awful.
The flash version is pretty good though. Grooveshark finally shut down :(
    Fun website if you like building computers. Targeted at desktop users, but there's a little bit of server class hardware on there too. You can also see price trends for the items you choose.
    Nothing special about the website, but it's really nice having the store nearby.
They have the absolute best prices on CPU's, and their motherboard combos are really good too. They've also been expanding into the DIY market some, they carry Raspberry Pi's, Arduinos, and Intel boards. They even have a model rocket section!
    Not cheap, but if you can afford it they have some really nice aluminum channel for building. Servo mounts, gears, driveshafts, gear chains, etc. Erector set on steroids.
    FreeBSD based OS for file servers.
I wasn't able to figure out how to set all the user permissions like I wanted when I was using it, but it keeps improving, and for a home NAS it could work pretty nicely. ZFS filesystem too.
    Students: Free Microsoft software.
    Schematic and PCB design software. This is what I use. Nothing fancy, but it does the job and it's free.
    Nice light photo viewer.
    For the Canon camera owners, this is a really cool website. RAW video on a 5D MKII(I)! Lots of added functionality. And if you do the raw video this is a nice viewer/converter:
    Free video editor. It's serious about the minimum specs though. While not strictly required, you should have at least 16GB of RAM and a good GPU for this.
    A good place to look for a new laptop. Some of the best prices, and lots of options.
    Horn loaded speaker website. Some really good info on there about sound in general too. I have a pair of the DR 250 and Titan 48 speakers, and I'm pretty happy with them.

This may be updated as I come across / remember other things.

Saturday, April 18, 2015


Aaahh! It's April already! Time is moving so fast it's scary. College is really hard.
Why must the nicest weather of the year coincide with exam study time?
I wrote this up a while ago, and am just now posting it in between studying for exams. I've been doing nothing but math for the past 6 hours, and I need a brain break or I think my brain will break.
I realized the other day that I haven't really posted any pictures from college, so I'll make an attempt to rectify that from now on. First though, new computer setup!

Never seen that error before...

It's working pretty nicely. The main reason I'm running Windows is that the free version of Davinci Resolve (Davinci Resolve lite) only runs on Windows. From what I can tell, the paid version runs on Linux, but I don't have $1000 to spare, and since I'm a student, I get Windows for free, so...
I'm really excited for DaVinci Resolve 12, I'll probably move to that as my primary video editor. (except on Linux...) Resolve can even do real-time optical flow interpolation, which is the coolest thing I've seen in a while.

New system specs: (Subject to change fairly often)
CPU: 2.5 GHz Xeon x8
GPU: Nvidia GTX 590
1 TB 7200 RPM SATA drive (Windows 7)
256 GB SATA SSD (Linux Mint)

So now I've got a good setup for CG and video editing, if only I had time to use it... I'm hoping to put it to use for the CRU VMA's next year. There are some nice computers in the video editing department at GMU, (i7 3770 with 16GB RAM), but they're rather lacking in terms of the GPU. (At least the ones I've tried, the mac pro computers may be better)

Anyway, photos!
Spring is beautiful.


 These are all raw, completely unedited, and some of them were taken with my phone. I did see enough good photo opportunities I've started bringing my camera. The Canon PowerShot G series is a really great all-around camera. It's small enough to bring easily, and still gives me all the control I need, and good photos. The new ones have HD video too. I'm very happy with my G10. I've put it through a lot, and it still delivers. I need to clean the lens though, as you can see in the photos above.
That's all for now.

Friday, March 13, 2015

Me and VMA shooting

Getting started on VMA's early this year...

Mostly generic guitar shots that could be used on various projects. I didn't realize until this project how nice the full frame sensor is on the 5D. I should have put magic lantern on it for this project, I'll try to do that for next time. It makes video shooting so much better. We didn't check focus except on the built-in camera screen for the first round, so we had to shoot that all again. 
Note to self: bring HDMI monitor next time, even if it's only a 5" screen, almost anything is better for checking focus than the 2" camera monitor. Magic lantern's focus peaking would have been very helpful.

We also did some other shots, I'm not sure how many of these will be used, they were more specific, but it was a very interesting shoot. Without revealing too much;

That is snow in the background, and the stick was an essential piece of equipment :)[]

Thursday, March 12, 2015

Speaker Progress 07

Amazing what can happen when I get time to work on things... With (a lot of) luck I could have it finished this week...

To date:

Trying out fitting for the back brace... Lots of routing on this piece.

Most of the (wood) parts for the tweeter module

I let my little sister have some fun with part of my speaker that doesn't show and won't get painted...

Marked for nailing

There's a minor problem...


Is supposed to look like this.

Much better. Glad I hadn't glued anything yet. Tack nails only so far. That will change soon.

I know, I said I should put this in slideshow format, but maybe next time. Or maybe long posts aren't so bad. It's late, that's all for now.