Hand crafted SP with ONKYO "OM-OF101" vol.2 - assembly

Today is usually the last day of summer vacation for children.

Some areas have extended the summer vacation for COVID-19, so it will be hard for parents and teachers to take care of them.

I've been working on assembling the speakers since last weekend.

It's a simple bass-reflex structure, so it's easy to assemble in order, but there are a lot of difficulties due to the lack of precision in cutting by amateur.

The first step is to attach the auxiliary reinforcement plate and duct plate to the baffle plate.


The duct board is screwed so that it can be adjusted later.

Glued the diagonal side panels and side panels on both sides of the baffle board.


There is still a gap at the diagonal cut point. It may look like a straight cut, but it's probably slightly crooked. When the bond is dry, fill in the gaps with wood putty.


Install the back plate.


Lightly fill it with sound-absorbing material.


The back plate is made of the same size plate screwed together so that it can be adjusted later.


This is what it looks like when the back plate is attached.


Glue the top plate.


Due to poor cutting accuracy, the diagonal side panels and the top panel were out of alignment. If I get motivated later, I will try to adjust them by planing.

The box volume is about 10.5 liters, and the tuning frequency of the duct is calculated to be about 75Hz.

This is a little larger than the example and recommended box, and the duct frequency is lower, so I hope it will produce a relaxed bass sound.

After preparing the speaker terminals and the speaker unit, I found out that I didn't have any Faston 250 terminals in stock! Have to buy some.

As a result, this speaker craft will not be completed until after this weekend. So, I may try painting it with water-based varnish.
posted by toons at 13:06 | Audio


Hand crafted SP with ONKYO "OM-OF101" vol.1 - prologue

The long rains during the summer vacation are finally over. I was hoping that the weather would become a little more like autumn, but the heat of summer has returned once again.

I got the ONKYO "OM-OF101" speaker unit, so I designed the box image, did a rough calculation of the capacity and ducts, and managed to make a cutting diagram of the wood, but ... I didn't feel like cutting in this intense heat.


With the SDGs in mind, I tried to make effective use of leftover scrap wood as much as possible. I used leftover shelf boards for the bottom panel, OSB plywood left over from DIY for the baffle, and scrap MDF for the rest. The only thing was to get four pieces of MDF (300x300mm) for the backing board.

Just looking at the blueprints didn't help, so I made up my mind to start the cutting work!

Taking care not to disturb the neighbors with noise, I started work at 11:00. I finished all the cutting work in about two hours.

I took my time to cut the diagonal cut carefully, so I was able to get good accuracy. However, the last part of the work, drilling the square holes in the back plate (for adjusting the ducts and sound absorbing material) with a jigsaw, was a bit of a pain.


It looked squishy in the picture, and I felt like I've run out of energy here. I was sweaty at the limit of my strength. This was not a place to be seen, so I left it like this.

Finally, it is an image of the OM-OF101 mounted on the OSB plywood baffle.


After a while, I'd like to do the assembly in a cooler place.
posted by toons at 19:47 | Audio

New updated - "Audio Tone Generator - ATG" ver 6.0


"Audio Tone Generator - ATG" has been updated to ver 6.0 today.

"Audio Tone Generator - ATG" is a powerful reference Audio test signal generator app for iPhone.

It creates the reference audio test signals as Sine wave, Sweep signal, Chirp signal, White Noise and Pink Noise, and has a frequency accuracy of 0.1Hz.

In addition, it can generate octave band noise of 1/1 or 1/3 octave in NOISE mode. You can also use it for detailed analysis of specific frequency bands.

In the latest version, chirp signal generation and preset frequency customization functions have been newly added.

In the latest version, the UI design has been revamped, and the chirp signal generator and preset frequency customization are now available.

- Sine wave : 8000Hz

- Sweep signal : 20Hz - 20000Hz

- Chirp signal : 100Hz - 16000Hz

- White noise

In addition, it can generate octave band noise of 1/1 or 1/3 octave in NOISE mode. You can also use it for detailed analysis of specific frequency bands.

- Octave band noise : Pink noise , 1/3 octave band , center frequency 3150Hz

You can also customize the preset frequencies in sine wave and sweep signals. You can set buttons for frequently used frequencies.

- Preset frequency setting example (sine wave)
atg_sine_preset_2.png atg_sine_preset_2_v600.png

This app can be very useful for a variety of applications including:
- Testing for Loudspeakers and Headphones
- Burn-in for Audio equipment and Loudspeakers
- Testing and tuning for Audio amplifiers, Equalizers and many other Audio equipment.
- Acoustics testing
- Frequency response measurement for Audio systems using White noise and Pink noise
- Sound Masking
- Relaxation and Meditation
- Hearing Test
- Mosquito sound creation for teenagers

If you are interested in this app, please click the following link to display on the product information of App StoreTM.

posted by toons at 04:47 | News


Got ONKYO OM-OF101 full range speaker unit!


I got the ONTOMO mook No.12 magazine with ONKYO "OM-OF101", 10cm full range loudspeaker unit as a supplement.

It's a pity that it was released at a time when the summer vacation is almost over.


This unit uses a technology called biomimetics. According to the article by the speaker unit developer, they traced the wings of a dragonfly.

It looks a little weird in the picture, but it doesn't look that bad in the actual unit.


Comparing it to FOSTEX FE83 that was lying in the corner of the room, it shows the size of the unit diameter and magnet size. The weight of the unit was just under 800 grams, which seems to be a lot more than the 565 grams of FOSTEX FE103NV.


What kind of SP box should I build for this unit?

I'm going to try the orthodox bass reflex system, but looking at the units, I think a slightly larger sealed system might also work.
posted by toons at 12:28 | Audio


Animated clouds!


Huge rain cloud seen in the eastern sky from in front of Nijo Castle!

It looks like an animated cloud.


To my eyes, it looked like a big bird spreading its wings over the main cloud.

It was just a clear day in Kyoto, so I was very impressed by these fuzzy clouds.


When I checked the rain cloud radar, I found that it was a huge guerrilla cloud. The timing was about 15 minutes before the radar image, so it must have been moving north around Otsu City.

If its course had shifted even a little to the west, Kyoto City might have been hit by a heavy downpour.
posted by toons at 19:51 | diary