New 3" Full range TL

Bambinz

Member
2017-04-25 6:28 am
Hi All,
I follow this fantastic forum from many years :D
Now I would like to realize a new project with yours help :D

Frome some years I have two full-range speaker made with the TB W3-871 loaded in DCAAV, these are the speakers dimensions's and the simulation:

simula10.jpg

dimens10.jpg


I am very happy from the results.

Now I would like to realize another two monovia but loaded in trasmission line/back loaded horn. First to try another type of load and second to take better care of the design/color of the speakers.

I'am thinking about somethings like this:
image018.gif

image020.jpg


The speakers shuold be for a desk, therefore the speakers dimension of the previous image, 400x235x100, should be OK, but not bigger.

Now, the budget for the speakers is not too high, therefore I don't know if remain on the w3-871 or another driver like this.
3" or 4"?
Can you suggest me some speakers in the same price range of the W3-871?

I'am trying to understand how works hornesp to simulate this type of load, have you any guide or tips to start the simulation?

I prefer to simulate and realize my own project, though maybe works worst than other projects :D

Excuse my bad english, but it is not my first language :(

Thank you very much in advance for your time and help!!
 

Bambinz

Member
2017-04-25 6:28 am
Some little questions :D

For the Hornesp simulation, I choose:
- Quarter Space
- Loudspeaker type: Horn loaded
- Horn Load:
At this point there are the first problems, I don't know these types of loads :(
I think that I should choice, in my case, beetwen Back loaded or Offset Driver. Now, Which are the differences?

- Number of segments: Also in this case, How I can choiche the number of segments?
- Flare profile: I think that the conical is the most easyest to built, therefore I will choose this.
- Throat Chamber, Thoart Adaptor: What are?

Thank you very much
 
Doing a little TL is difficult (TLs tend to be big). Have a look at teh Woden Baby Labs for inspiration.

Little “horns”, as you have shown, are really just badly designed TLs — they are not big enuff to supply any real horn load.

I put my W3-871 into a 1.5 litre sealed box.

A folded TABAQ is another possible candidate.

dave



dave
 

Bambinz

Member
2017-04-25 6:28 am
Hiii xrk971,
Thank you for the information. The Cornu Spiral Horn seems to be funny but very very ugly xD Probabile the WAF (Wife acceptance factor) is -inf. ehehehe.

I think that whit a 5in driver the speaker become too large for a desk :(

EDIT:
I have do some simulation with a the W3-871SC, this is the result:



I think that I can put this TL with mass-load in a box of dimensions arround the desidered max value.
What do you think about this simulation?

Thank you again :D
 
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The bass peak to too sharp - try rolling it off slower and less peaky. Take a standard Tabaq MLTL as your starting geometry and go from there. I think your volume is too small for the driver's Vas and the tuning too high so it is peaky. Try increasing vol/length and lenght of vent. If you want a compact TL, pick a driver with a powerful motor (Qts in mid 0.35 range), and smaller Vas. Only one in 3.5in range that comes to mind is Scanspeak 10F/8424, Faital 3FE22, or FR88EX. But tune them to maybe 75Hz. They won't go deep like a moderate Qts 3.5in driver in a MLTL but will sound cleaner in a tapered TL.
 
Could you please explain me the differences between the transmission line and the horns?

A TL is a pipe that is closed at one end (quarter-wave resonator) or open (or closed) at both ends (1/2 wave resonator).

The former is the most common, and can taper from large to small (at the terminus), a straight pipe, or an expanding pipe. The 1st taper allows for a shorter pipe, the expanding pipe needs to be longer.

Mass loading is having a restricted terminus… often a duct just like in a reflex box. If you take an approximately cubical bass reflex box and start extending one dimension (but keeping the same volume), the BR slowly mutates into an ML-TL. The tunign in an ML-TL is usually lower.

A horn is an expanding pipe open at one end. Expansion can be linear as in a Voigt Pipe, or have a range of more complex expansions (as often clearly seem in higher frequency horns. The driver can load a chamber and then the chamber vent into the pipe, or the driver can be tapped into the horn part-way along.

As in a TL, the positioning of the tap (Zd) can be used to mostly kill the 1st unwanted harmonic.

Lines can be damped to help kill pipe resonances. With sufficient damping the pipe becomes aperiodic (with requisite changes in impednce profile).

dave
 

Bambinz

Member
2017-04-25 6:28 am
Thank you very much Perceval and Planet10.

I have do other simulations, seems to be that with the Mass loading there is always a sharp bass peak (with these little driver) and I am not able to eliminate it.

Whit a relative small straight pipe and the driver TB 871 I obtain this:

The dimension is:
- Length = 110cm
- Area 55cm^2

Seems to be a good response, no?
Another simple questions, in hornesp the acoustic power is calculated at maxpower or at 1W?

Thank you again for your time and help!
 
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Bambinz

Member
2017-04-25 6:28 am
Thank you planet10, i try to add more damping.
And the other simulation, The normal TL, what do you think?
Do you know how to simulate the Babylabs in hornesp? Because there are 3 segment with different cross section and I am not able to put this three segment in hornesp.