First Build - Qts, Sound Characters, and TQWT

[jwicaksana]

Technically, none of them, it ideally should be recessed flush to match the frame shape.

FWIW, what I usually did was make a foam or similar 'false baffle' to cover the driver and surrounding area like is [was?] commonly done for dome tweeters and should work fine for your circular recessed version.

GM

Greg, I did as you said, and it seemed to have enhanced the lower range, and overall presence of the sound. I folded a felt fabric, inserted 1mm foam inside and used some bluetak to hold them in place. Thanks for this great tip.

 

[GM]

Greets!

What the pot does is lower the upper mass corner [Fhm = 2*Fs/Qts] by 'weakening' the motor's effective 'strength', i.e. BL drops and Qes, Qts goes up, ergo efficiency goes down above this point to create a flatter response over a wider band-width [BW] at the listening position [LP].

This is a 'poor man's' baffle step compensation [BSC], which uses a resistor, inductor and by-pass resistor, which you can do instead, but it costs a lot more and may not 'sound' any better once a fixed resistor grid composed of otherwise cheap components: General Speaker Related Articles

GM

 

[GM]

Thanks for this great tip.

'Sounds' about right 😀 You're welcome!

Now that you're a believer, consider spending some time 'down the road' when the present configuration's 'tone' is ingrained and experiment with different materials, thicknesses to see if there's a better choice overall as there often is IME.

One set of speakers I did wound up with a foam pad that covered a goodly portion of driver and the area around it, with a hole barely exposing the DC/whizzer and a little stuck on star like used to 'grade' kid's kindergarten papers on the DC.

Combined with an 8 ohm carbon comp resistor in series along with a few other 'de riquer' tweaks required for cheap drivers, this 5.25" mobile audio 'FR' driver measured nominally flat from ~40-12.5 kHz using MLS in a ~48" tall MLTL and its owner still prefers them over more expensive, known to be better overall CSS drivers that by all accounts need little/no tweaking that I've tried in them.

GM

 

[hollowboy]

Here with no drivers and freshly clad in very thick yew veneer (which showed up some issues with bracing that we still need to fix). They have since had some rebates & the sharp edges softened.

Can you please elaborate on this very thick veneer - where you can get it, is it a ply or a single layer?

 

[planet10]

elaborate on this very thick veneer

Cut from yew boards by Bernie. It is about ½" thick. In this case scraps left over from other projects.

dave

 

[jwicaksana]

 

[jwicaksana]

I decided to give this project a reboot. I've listened to the open baffle and decided I'll try a transmission line design anyway. TABAQ design by Bjorn looks doable to me, so on I went with the cutting plan and material sourcing.

The driver will benefit from some conditioning, I hope:








And I used 15mm MDF for this project: