New DIY speaker model G8 :)

dcibel

This speaker, like many of mine, comprises of speakers obtained via classified ads, seconds hand etc to save a few bucks over retail new costs. I try to only buy items that I have a plan for, not just because it's a good deal. I had been using a pair of NHT Xds speakers at my computer since my recent relocation, and while they are a great speaker, they’re small and sealed so don’t have much for low end punch, even when I added some EQ. I wanted something a bit more substantial to enjoy while I work.

 Enter the Wavecor WF152BD04. I think I got these from Leon, don’t remember what I paid, but they’re worth every penny spent. This is a 4 ohms midwoofer with excellent specs allowing for a nice deep response in a small enclosure. It modelled out to a extend down to 40Hz in only 11 Litres. The response is smooth with mild breakup and the a clean low distortion sound. This is a top drawer midwoofer let me tell you!

 

 

The tweeter is a Motus UH25CT1, found on Canuck Audio Mart for I think CAD$100 for the pair. Completely unobtainable today, unfortunate as it is a great performer and somewhat unique. When it arrived I had forgot it was a neo driver due to the size, and was surprised to pick it up and it was very light weight. It turns out that Motus in their wisdom, instead of spending a lot of RND time designing cleverly shaped non-resonant chambers, solved the back wave problem by simply making the rear chamber very large. It has a larger than average face plate, and a thick plate that hides the screws on the rear side which gives this tweeter a unique and clean look. That is if you could ever keep it clean. The matte finish is like 400 grit sandpaper, breathing near it leaves a mark. But I had a plan, eh!

 

I had always wanted to try the Visaton WG148 waveguide, and this project was a good fit. The tweeter has a completely flat plate, so attaching the waveguide was easy. This dome is a bit small for the waveguide, as it’s a real 25mm dome, and the throat of the guide is more like 38mm, but the flange of the front plate meets up with it nicely, and the resulting response is perfectly usable. Visually the waveguide is a good pair for the woofer, very similarly sized at 148mm vs 152mm, and it also puts the acoustic offset between the drivers at near zero.

 

For the cabinet finish I used a Di-Noc faux wood “Bubinga” product. It’s not cheap, but application is quick and easy compared to real veneer. Just peel and stick and enjoy. It’s very thin so you do have to make sure the serface is very flat and clean, any spec left behind when you stick this stuff down will be a permenant bump in the gloss. As a gloss vynil its also somewhat fragile, easily scratched so handle with care.

 

 

The baffle and rear are finished with Rustoleum “Multitexture Aged Aron” textured spray paint. Nice stuff but a can doesn’t go very far, much less coverage than regular spray paint. The result is like sandpaper, so it was top coated with satin clear coat to take down the grit a bit making it easier to clean and more durable.

This cabinet is rear slot ported, the slot is the entire width of the cabinet and runs all the way to the top, 3/4” open at the bottom out the back, and 3/4” open at the top into the enclosure. Nice when the math works out like that.

 

 

There were numerous “happy accidents” made putting these together, but I won’t go into details on that so you’ll never know how bad I really am at cabinet construction. Yes, there is a cross brace between the midwoofer and tweeter, not shown above. The mitre cuts didn't take much longer to do that butt joints, and I think the assembly was a fair bit easier, if you notice how many clamps I didn't use.

 

Onto the design. I started out trying to use 2nd order slopes, because I am using a high end tweeter in a waveguide it should be able to handle it. It did, but in the end I was able to achieve a better response and sound with the classic 4th order L-R.

 

Here’s what I had to work with, raw driver measurements in-box.

 

And here’s the modelled response in my design.

 

Now that the speaker is complete and assembled, here’s the measured gated response overlaid on the simulated design.

 

 Not a bad match

 

A photo of my crossover assembly, this photo is missing an extra resistor that came late and makes the magic happen. I didn’t take a new photo after installing the last part.

 But how does it sound? Great! This has everything just right, and while the NHT Xds is a great speaker, they sound wimpy and thin next to this pair. The low end has authority and punch, and the midrange through the treble is effortless. There’s nothing missing or lacking or anything that stands out, just music as it should sound, and with the weight and tone that I prefer. Sometimes getting the tweeter dialed in just right can be tedious, but not this time. Maybe I’m just getting better at this

dcibel

Some photos of the finished product.

 

And a photo of them in their home at my desk. Not ideal with a big reflective desk under them, but I can easily apply EQ at the source to help that out a bit.. The crossover design was for overall flatness so I can use them where ever I want, it wasn’t purpose designed for this near field desk location, in my mind that sort of thing is what EQ is for.

dcibel

Oh I forgot the normalized polar plot. A little dip in the directivity at 5-6kHz, otherwise looking pretty good

BrannigansLaw

Great work! I have a set of the Rival 120ACBs that look suspiciously like these, and am quite impressed with their low end performance as well. And your cabinetry puts mine to shame

6thplanet

Hell yeah! Those look great.

Tom_S

I love that baffle color against the (fake) wood tones. Great job with the little extra touches too, like the chamfer on the back panel.

DanP

Awesome.  Can't say enough good things about Wavecor drivers.  Nice clean look on the cabs and it looks like you nailed the xo.

squamishdroc

The faux wood turned our great! Have always wanted to try those Wavecor drivers.

dcibel

Thanks, the best thing about the Di-Noc was the time involved. Unlike a real veneer, there was no work involved to finish it, I was done in about 1.5hrs and only needed a pair of scissors, a razor and a straight edge.

The wavecor WF152 sounds amazing, very punchy low end for a small driver. If you want to try them, I'd jump on the current sale price at Solen for the WF152BD03 or 04 (8 ohm and 4 ohm variant, I'm using 4 ohm here).

squamishdroc

dcibel said:

Thanks, the best thing about the Di-Noc was the time involved. Unlike a real veneer, there was no work involved to finish it, I was done in about 1.5hrs and only needed a pair of scissors, a razor and a straight edge.

The wavecor WF152 sounds amazing, very punchy low end for a small driver. If you want to try them, I'd jump on the current sale price at Solen for the WF152BD03 or 04 (8 ohm and 4 ohm variant, I'm using 4 ohm here).

Oh - on sale at Solen eh?

dcibel

Sweet deals eh

https://solen.ca/products/speakers/home-speakers/mid-woofers/wavecor-wf152bd04-15cm-paper-cone-midbass/

https://solen.ca/products/speakers/home-speakers/mid-woofers/wavecor-wf152bd03-15cm-paper-cone-midbass/

Kornbread

Why the rising top end and big peak @~8k?

dcibel

Well it's not a floppy poly cone, and isn't doped or damped with a coating of any sort, so what you see is the cone breakup at high frequencies from the fairly ridgid paper. It's really not bad, high enough in frequency to not adversely affect my crossover slope with a 2kHz filter, and doesn't show up as big peaking harmonics in the HD plot like a metal cone.

Keep in mind that my raw in box measurements include the baffle step and diffraction effects. This woofer has been tested in Zaph's blog as well as Hificompass I believe if you want some more reference data.

dcibel

Something I could have included in the write up above, here's the response with my filters in place, so you can see the rolloff of each driver, and the crossover frequency at 2kHz.

And here's the filter transfer function, as you can see the midbass response did not require any extra notch filter to address in this design.

Zaph's data for the woofer:

Wavecor WF152BD03-01

[Image] - Thiele / Small parameters
[Image] - Frequency response
[Image] - Harmonic distortion
[Image] - Impedance zoom
[Image] - Cumulative spectrum decay
[Image] - Le(x) plot - impedance at excursion

Hificompass unfortunately doesn't have data for the WF152, but you can look at the WF182 or WF120 over there.

dcibel

Wavecor WF152 has now been tested by AudioXpress / Voice Coil:

https://www.audioxpress.com/article/test-bench-the-wavecor-wf152bd03-04-paper-cone-midbass-woofer

rjj45

dcibel said:

Wavecor WF152 has now been tested by AudioXpress / Voice Coil:

https://www.audioxpress.com/article/test-bench-the-wavecor-wf152bd03-04-paper-cone-midbass-woofer

Wow! Very low Le(x), very,very low distortion, and good CSD. Worth the money, as far as I can tell.

jr@mac

rjj45 said:

dcibel said:

Wavecor WF152 has now been tested by AudioXpress / Voice Coil:

https://www.audioxpress.com/article/test-bench-the-wavecor-wf152bd03-04-paper-cone-midbass-woofer

Wow! Very low Le(x), very,very low distortion, and good CSD. Worth the money, as far as I can tell.

Know anybody with a pair?

dcibel

Any of you guys with the Rival woofers have Wavecor motors, only the soft parts are different on the Rivals, and a different paint coat on the frame, Wavecor has a much finer texture to the paint, at least compared to the Rivals I have.

PWRRYD

Your enclosures look very nice and the measurements look awsome.  I'm sure they sound great.  My only suggestion is that you work to improve your crossover construction techniques and soldering skills.  I hope you take this as constructive criticism and not a slam on your project.

Wolf

I'm sorry, but the Rivals are indeed different. The vented poles are not the same between the makes. The Rival frame is an open-source part, and they are made in Canada, not China. I've not looked at the copper extended pole on the Wavecors to see if that part differs, but it could be the same pole I suppose. Sure- they look similar, but I'm not buying that they are indeed synonymous with Wavecor motors.

dcibel

PWRRYD said:

Your enclosures look very nice and the measurements look awsome.  I'm sure they sound great.  My only suggestion is that you work to improve your crossover construction techniques and soldering skills.  I hope you take this as constructive criticism and not a slam on your project.

No offence taken, however I don't see the need to put a lot of work into making the bits you don't see any prettier. The crossover is perfectly functional, serviceable, and all solder joints are good, I assure you. There's a few more dabs of hot glue then what it pictured above, to avoid any vibration. I probably won't change my methods here, as a finished assembly in the cabinet, it's not very likely that I'll ever look at it again once the project is complete and buttoned up.

On my desk pictured above, I have some parametric EQ built in at my PC to compensate for the near field location and desk reflection at 200Hz and resonance at 132Hz. It sounds amazing, couldn't be happier

I should have taken some more photos when the sun it out to show how that faux wood finish really pops in the light.

dcibel

Wolf said:

I'm sorry, but the Rivals are indeed different. The vented poles are not the same between the makes. The Rival frame is an open-source part, and they are made in Canada, not China. I've not looked at the copper extended pole on the Wavecors to see if that part differs, but it could be the same pole I suppose. Sure- they look similar, but I'm not buying that they are indeed synonymous with Wavecor motors.

I've compared them side by side, the motors look flippin identical, that includes the pole vent and extension shape that is easily visible through the voice coil holes. There may be differences between models based on motor size and coil diameter, but that's the only visible difference. If one is ordering parts from Wavecor as an OEM, you can order some customization if the qty is high enough, so I wouldn't rule it out.

The frame is an "off-the shelf" part sourced from China, Wavecor is using a different paint finish is all. I can't speak to the "Made in Canada" claim, the internet says "at least 51% of the total direct costs of producing or manufacturing the good must have been incurred in Canada", which certainly means that much of the product could be produced elsewhere, especially if assembly and QC in Canada is the most expensive part of the process. The Rival parts I purchased came in unmarked boxes, the packaging and parts themselves contain no indication of manufacturing source, the only reference to any existence of the company location is on the RAD site.

Wolf

Mine did not come in unmarked boxes, have a large 'Rival Acoustics' logo sticker with slogan, and say 'Made in Canada' on the boxes of all 4 of my Rival drivers. The pair of Kevlars I have came right off the assembly line and shipped to me, or so I was told. The round colored sticker also on the boxes was for relation of finished product to normal destination or clientele. Rival OEMs for other companies in Canada, and I as well as others were not privy to the names related. At least, bare minimum, the soft parts are different.

dcibel

I guess I got the super OEM models, but not that important anyway. Just a teaser, down the line I am looking at a 3-way design from the drivers pictured below. They are "high kevlar content paper", and these drivers should have oodles of overlap to ensure as ideal crossover slopes as possible. Tweeter is Wavecor TW030WA11.

dcibel

One of these impedance sweeps is a Wavecor 152mm driver with a 32mm voice coil, and the other is a Rival 152mm driver with a 39mm voice coil.

dcibel

Anyone wondering, the Rival drivers Gowa just posted about are the same pictured above, and the impedance sweep as well.

No one wanted to take a stab at which is a Rival an which is a Wavecor?

Tom_S

They both have that bump at 1500Hz - that's interesting. I'll guess the top chart is the Rival. Did I win a prize?

dcibel

Tom_S said:

They both have that bump at 1500Hz - that's interesting. I'll guess the top chart is the Rival. Did I win a prize?

You're a winner! Yes, the Rival driver with its larger coil has a bit lower Fs, lower Le, and slightly higher overall impedance. However, they are more similar than different, hard to say it isn't a balance drive motor from visual inspection and electrical sweep.

The bump at 1500Hz, simply a function of cone geometry. The bump is down at 800Hz IIRC on my 8" driver. It marks the frequency where the speaker no longer operates purely as a piston.

dcibel

Yuck! You don't realize how dirty those waveguides are until you shine some light and take a photo..

dcibel

dcibel said:

The bump at 1500Hz, simply a function of cone geometry. The bump is down at 800Hz IIRC on my 8" driver. It marks the frequency where the speaker no longer operates purely as a piston.

I wasn't entirely accurate when I posted this. The bump in the impedance and corresponding dip in the frequency response is a result of the specific frequency where the surround is moving out of phase with the cone.

squamishdroc

dcibel said:

Yuck! You don't realize how dirty those waveguides are until you shine some light and take a photo..

Nice! With this self isolation thing going on maybe we should start a "pictures of your speakers on the patio" thread