Design of Transmission line speakers

[ArjenShenzhen]

Dear fellow forum members,

Since quite a while im working on a TML design with 2 drivers of just 4" to make a small and rather portable speaker with good bass responce.

Ive gotten some drivers made to size, let me share the parameters with you:

Impedance : 4 Ohm
Minimum Frequency Response
: 85Hz
Reproduction Frequency Response
: Fo~18KHz
S.P.L. : 88.027 dB/W(m)
Rated Input : 10 W
Music Power : 15 W
Equivalent Diaghram Radius
: 45mm
Equivalent Mass : 2.825g
Magnet Weight : 262 g
Net Weight : 650 g
Fs : 85.106 Hz
Re : 3.6 Ohm
Mms : 3.148 g
BL : 2.357TM
Qts : 0.892
Qms : 4.904
Qes : 1.090
Vas : 7.295 Ltr
Xmax : 2.0 mm
no : 0.399%
Frame : Fe
Cone : Paper
Surround : Foam
Damper : Cotton
VC DIA : 0.8¨•
Material
Magnet : 9.2 OZ

Now im using these speakers in a TML enclosire designed for a Fs of 85 HZ, that makes the line itself 80 CM long. however ive noticed that my software, AJ horn shows a bump at about 140 HZ i can remove it by making the front chamber allot bigger, but in how far does that effect the bass tightness? im afraid it might make the bass sloppy and less punchy.

Does anyone have some experiances they want to share on this subject?

Thanks in Advance,

Arjen helder

 

[Henkjan]

given the rather high Qt, I would suggest tuning the TL lower, try 60 or 55Hz

 

[ArjenShenzhen]

Lower cabinet Fs

Hi there henkjan

Ive tried to simulate that in AJhorn, but it does not much with the peak and causes a big dip around 200HZ ive tried various lenghts, i think that maybe a hermholtz resonator at the given frequency might give a better responce.

Any experiance with larger front chambers?

Greetings,

Arjen

 

[planet10]

given the rather high Qt, I would suggest tuning the TL lower, try 60 or 55Hz

You will typically get less bass tuning to below the Fs (except maybe in an ML-TL -- which has 2 tunings)

dave

 

[Henkjan]

try to use the Allignment Tables from MJK as a starting point. then try to "play" with the driver position.