Desktop Transmission Line

Hi, first post. Interested in making some small desktop transmission line speakers with a full range driver. Only 300mm high but want to know driver size and recommended spec.
Bit of a transmission line fan owned a couple over the years and have a pair of PMC Twenty 23 now. Never made a speaker before but have built a Bottlehead Crack headphone amp some years back.
 
I'm in Beijing and so-called labyrinths pervade China's diy supply chain (ebay-like taobao/idlefish). I think there's sort of a continuum between Onken and TL, with MLTL somewhere in the neighborhood too. I have made many, both from scratch and by inserting dividers into single-slot Onkens. The key is to apply an approximate taper to the line, like the classic TL. One can experiment by brute-force stuffing cut/folded/pinned stiff cardboard through the driver opening, and with each addition the bass usually goes deeper and more authoritative. The results are obvious, instantaneous, and quite forgiving. It doesn't cost anything to try. Paper cardboard of course will tend to vibrate a little bit but can then be replaced with plywood etc. Maybe I'll start a thread on my Beijing diy, with pictures. By the way, I now call them T'Lonkens.
 
frugal-phile™
Joined 2001
Paid Member
I think there's sort of a continuum between Onken and TL, with MLTL somewhere in the neighborhood too

An Onken is a BR with a specific tuning (which it seems is often being abandoned) and slot vents doen the sides.

There is a continuum between sealed, BR, and the multiple classifications of quarter wave designs. ie one can transition from one class to the next closest with hybrids in-between. More comples enclosures require much more complex math to simulate.

dave

PS: a T’Lonken, is that another name for a Daline?
 
An Onken is a BR with a specific tuning (which it seems is often being abandoned) and slot vents doen the sides.

There is a continuum between sealed, BR, and the multiple classifications of quarter wave designs. ie one can transition from one class to the next closest with hybrids in-between. More comples enclosures require much more complex math to simulate.

dave

PS: a T’Lonken, is that another name for a Daline?
I would call the Daline a rear-slot floorstand "TLonken" ;)

Yes traditionally Onken is a slot-loaded BR (twin vertical slots "Vonken", and single horizontal slot "Honken" are both common, my nomenclature hehe), which TL is not, while MLTL is a BR-TL hybrid.

I must add that I'm no expert, having started diy during the (still-ongoing) pandemic, perhaps a dozen or two works-in-progress. My tools are very simple: Frequency Sound Generator APP finger-sweep/by-ear, "reference-quality" speakers such as ('90s) Monitor Audio Studio, a variety of drivers from vintage to space-age, and >100 front-row small-ensemble live concerts in my head. Design-wise I'm totally minimalist by necessity. Most of my projects cost maybe $100+ (excluding XO parts I hoarded years ago and re-use at will). Being in China, I often find OEM components for a song. My first diy design "after" Eve Audio SC205 digital active monitor ($1500/pr) using the original 5.5" fiberglass-honeycomb midwoofer, third-party bigger/louder/lower AMT, same rear-slot 7L volume as SC205 but a "TLonken" inside in lieu of DSP/EQ, and passive series-1st-order XO, at a total cost below $150 (plus a few Jantzen parts). With mixed feelings, I had to say the "HeilEve" trounced all my previous speakers in all-around realism and musicality.

I can also recommend a new whizzer-less full-range speaker line (4", 4.75", 5.5") variously branded Hifi-bird or Michael's Audio. Supposedly using UK "drum paper" whatever, they have superb micro-dynamic linearity (hence realism) reminiscent of vintage alnico speakers.

TLonken really works :)