Enginerding with Weeb Labs

[Weeb Labs]

I recently stumbled upon a wonderful little plugin developed by Denise called Bass XL. It makes use of the phantom fundamental phenomenon to dramatically extend the perceived low frequency response of a speaker or headphone. Having used this plugin for the last week, it has become a permanent fixture within my SoundSource stack and I would highly recommend it. Expect it to make an appearance in the upcoming DRC video.

The Denise store is currently offering both Bass XL and Sub Generator (generates harmonics in the opposite direction) as a bundle for €23. Waves sells something similar, although be warned that their solution does not run under Equalizer APO.

Valve implemented a very similar algorithm for their Index headset speakers, which sparked my interest. Measuring the perceived result is quite challenging for me at the moment, so this has been very experimental and involved quite a lot of "adjustment to taste".

 

[buscon]

Another speaker review in progress! This time, it's the M-Audio BX4 D3. They retail for €110 per pair and the design is sane.

I am considering buying these speakers, but I would like to read your review first
Do you know when you are going to publish it?

Thanks!

 

[somebodyelse]

The Bass Enhancer in PulseEffects does something similar to Bass XL.

 

[Weeb Labs]

I am considering buying these speakers, but I would like to read your review first
Do you know when you are going to publish it?

Thanks!

It will likely be published either tomorrow or on Saturday. If you are located within the US, then the Neumi BS5Ps are a much better option.

 

[buscon]

It will likely be published either tomorrow or on Saturday. If you are located within the US, then the Neumi BS5Ps are a much better option.

good to know, thank you!

I am in Germany, I cannot find the Neumi BS5P.

As an alternative I was considering the Alesis Elevate 5 MKII - do you have an opinion about them?

 

[Weeb Labs]

good to know, thank you!

I am in Germany, I cannot find the Neumi BS5P.

As an alternative I was considering the Alesis Elevate 5 MKII - do you have an opinion about them?

There exists no measurement data for the Elevate 5 but if you are located in Germany, then I would highly recommend a pair of M-Audio BX5 D3s. They are available as B-stock from Thomann and I have previously reviewed them.

 

[buscon]

There exists no measurement data for the Elevate 5 but if you are located in Germany, then I would highly recommend a pair of M-Audio BX5 D3s. They are available as B-stock from Thomann and I have previously reviewed them.

yes, I read your review and I was considering those speakers too... the Thomann b-stock is definitively appealing!

 

[pkane]

I recently stumbled upon a wonderful little plugin developed by Denise called Bass XL. It makes use of the phantom fundamental phenomenon to dramatically extend the perceived low frequency response of a speaker or headphone. Having used this plugin for the last week, it has become a permanent fixture within my SoundSource stack and I would highly recommend it. Expect it to make an appearance in the upcoming DRC video.

The Denise store is currently offering both Bass XL and Sub Generator (generates harmonics in the opposite direction) as a bundle for €23. Waves sells something similar, although be warned that their solution does not run under Equalizer APO.

Valve implemented a very similar algorithm for their Index headset speakers, which sparked my interest. Measuring the perceived result is quite challenging for me at the moment, so this has been very experimental and involved quite a lot of "adjustment to taste".

Curious if this is similar to the sub-bass enhancement in DBX PA2, but with more controls. I measured the effect here (three tones fed in @ 30, 60, and 120Hz):

 

[Weeb Labs]

Curious if this is similar to the sub-bass enhancement in DBX PA2, but with more controls. I measured the effect here (three tones fed in @ 30, 60, and 120Hz):

If you are referring to the sub-harmonic synthesis function, then the working principle is quite different. It actually bears greater resemblance to Denise Sub Generator, which generates subharmonics below an audible fundamental in order to add sub-bass to content which was not originally present.

Bass XL works in the opposite direction, taking an existing fundamental which the driver can not audibly reproduce and generating harmonic content above it which results in perception of the phantom fundamental.

 

[pkane]

If you are referring to the sub-harmonic synthesis function, then the working principle is quite different. It actually bears greater resemblance to Denise Sub Generator, which generates subharmonics below an audible fundamental in order to add sub-bass to content which was not originally present.

Bass XL works in the opposite direction, taking an existing fundamental which the driver can not audibly reproduce and generating harmonic content above it which results in perception of the phantom fundamental.

Yes, DBX is generating "harmonics" below the fundamental, so it is different.

 

[Weeb Labs]

I have been experimenting with off-ear BMR headphones, both as a solution for VR audio on the Quest 2 (or other HMDs) and a standalone headphone.

The enclosures are 3D printed (model borrowed from Thingiverse for prototyping) and the drivers are Tectonic TEBM35C10-4s. They begin to roll off around 100Hz but exhibit a sensitivity of 80dB/W/M, which leaves an abundance of headroom for DSP at a distance of 1.5cm. At the moment, I have managed to achieve an f3 of 35Hz without the aid of psychoacoustic bass and at rather high listening levels.

The standalone headband is still being modelled but I look forward to testing that.

I have also been experimenting with the larger Tectonic BMRs, which has been interesting. Expect to see spins for all of them soon.

 

[Weeb Labs]

My next loudspeaker review will most likely be the JVC XS-D629BM, which are currently rather popular and available from Currys in the UK and Ireland for €100. They make use of the TPA3118D2, along with tone controls and Bluetooth. I will have to wait until I receive them to determine whether there is any DSP or crossover implemented.

 

[Weeb Labs]

Review spoilers: They're mediocre out of the box and here are some preliminary measurements.

In-room on-axis:

Holy shelving, Batman! That was the very first audible problem that I noticed prior to capturing measurements. It begins precisely in the middle of the sibilance band. Isn't that lovely? The specifications indicate a frequency response of "40-20,000Hz" without bothering to provide specific values but unless they consider -50dB at 40Hz to be "output", that is an outright lie. Out of the box, there is very little output below 70Hz.


Driver components:

If you were expecting an actual crossover, then I'm afraid that I must disappoint you. We have a singular protection capacitor on the tweeter and nothing else. Hence the cancellation at 4.6KHz.


How about the directivity? Well...

It's somewhat serviceable. The on-axis waveguide diffraction at 12KHz should be sufficiently high in frequency that it ceases to be an audible concern in most rooms. For near field use cases, this should also be fine.


Schmoo at 76dB.

Unremarkable but below the threshold of audibility where it matters the most. IMD may be another matter entirely.


On-axis response following correction:

Much better. We now have a more reasonable F3 of 57Hz and the ear-piercing shelving has been eliminated. It sounds perfectly fine in this room and I will include a relatively meaningless A/B comparison below.

TL;DR: Unless you intend to correct these, please don't even consider purchasing them. Frustratingly, the CS Bluetooth module found in these units that handles source switching includes ten bands of PEQ. Was the R&D budget really so small that a lone engineer couldn't have taken a prototype out into the nearest carpark with a UMIK-1, captured a single on-axis ground plane measurement and written the resulting filters to the CS? The result would have been a product with a far greater value proposition out of the box.

I will still be publishing a proper reviewing the coming days, complete with the usual CEA2034-A and other more detailed data.

 

[Weeb Labs]

Early ground plane results. With the bass tone control in the default position, I was initially convinced that there might be a problem with my measurement but no; it is simply a terribly implemented control.

Here you can see the effect of the bass tone control in the 0%, 25%, 50%, 75% and 100% positions.

 

[tomtoo]

I would be intersted what you could do out of the bx3 with a little love. Its a shame what they made with this chassis.

 

[Weeb Labs]

I picked up a pair of Cambridge Audio Minx MIN 22s this evening and they have been a rather pleasant surprise. Much like the MIN 12s, these are 2.25" BMR drivers with a claimed 180 degree directivity.

Note that despite appearances, the lower driver is not a BMR; it is simply a flat coned midwoofer selected to match the appearance of the BMR above it.


Here is a quick in-room measurement on my desk.

We have reflections around 600Hz and modes below that, both of which can be ignored. I paid EUR 90 for this pair and this is rather impressive performance. I will take these outside tomorrow and capture some anechoic measurements, which I anticipate will be rather flat.

Let's take a look at directivity. These measurements are quite low resolution but directivity looks rather good. It is smooth and off-axis response doesn't drop below -8dB until we are a whopping 90 degrees (cyan line) off axis! Not unexpected for a BMR driver.

Breakup doesn't set in until just above 16KHz, which encompasses the vast majority of the audible band.


Then we have distortion at 76dB/1M. First as a percentage.

And then relative to signal.

This is really quite impressive. We are reaching down to -60dB at 8KHz.

Finally, some nearfield driver measurements. Green is the midwoofer and orange is the BMR.

Capturing meaningful nearfield measurements of these drivers is quite tricky, as the BMR's directivity is extremely wide and it is in very close proximity to the midwoofer.

On the whole, I find these little speakers to be rather impressive. Paired with a cheap subwoofer and given appropriate correction, they would make a lovely little desktop monitor.

 

[restorer-john]

I paid EUR 90 for this pair and this is rather impressive performance.

Not so impressive is the price here. Between AU$319 and AU$399. Each!

 

[Weeb Labs]

Not so impressive is the price here. Between AU$319 and AU$399. Each!

That's a little bit outrageous! They're ordinarily available for about EUR 170 per pair here in Europe.

 

[thewas]

That's a little bit outrageous! They're ordinarily available for about EUR 170 per pair here in Europe.

On the other hand here ins Europe you can get often a pair of active JBL 305 for 200 € which probably beat them in most objective measurements.

 

[dannut]

little speakers to be rather impressive

Ditto. Some folks just can't have even a cute little Kef Egg in their system, then these come to the rescue. Requires funny system tricks to not get annoying sound from them (highpass >160Hz + multisub below, with main sub centered and elevated...)

Limited dynamics thou.