real efficiency tham 15 martinsson

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On the net there are these graphs related to tham 15 loaded with 15tbx100, but which of the subjects is correct?

There is a big difference in decibels ...

I would like to compare them with the emissions of "turbosound 118" and other basses to make the bass more performing for my use.

THAM15-10.jpg

THAM12_FINAL_HRSPL1PI_BC_12PS100_VS_THAM15_15TBX100_W_TEXT.jpg
 
You have presented some graphs and you want to know if they are correct.
So firstly what is the input data for the Hornresp sims?
Is the input data correct to the layout of the speaker and how well has the path been simplified to suit the limited amount of sections in Hornresp? Hint here is to check the reported volume in Hornresp and see how closely the internal volume of the cabinet layout compares.
Obviously check the driver parameters, voltage and speaker placement - 2pi is commonly used for comparison.
What data have you for the Turbosound 118? - this is not a complete description of any Turbosound cabinet I know - It will use a custom driver and a cabinet layout that will not be freely available, so how are you going to compare it?
 
The Turbosound Bandpass horn - that you show in your picture would be about right at 105db/W - But needs to be simulated in multiples to get the low end extension correct.
The Tham box would be about 100db/W - Its advantage is based on its small size rather than its efficiency. Multiples of the tapped horn will not show the gains in low end performance that the bandpass horns will when used in groups.
The reflex cabinet will probably be 96db/W or less, so that's why the Tham has more energy. if you are concerned about efficiency of the speaker system I would look at a bigger design of tapped horn than the Tham series.
 
which tapped horn do you recommend that be as efficient, as compact as possible?
jbell ss15? or 18" version (Xoc1 ) tham18?

will have more efficiency in the 40-80hz band 6tham15 or 4 tham 18?

Small, efficient, low bass - pick any two.

Hoffman's iron law.

I usually pick a low-frequency cutoff and then play around with the other two, favouring smaller cabinets and using multiples to get SPLs up.

Chris
 
Multiples of the tapped horn will not show the gains in low end performance that the bandpass horns will when used in groups.

I've often heard this repeated, but I haven't seen any empirical tests to back it up, and the sims suggest otherwise. Granted, the change is not as large as say that for a FLH (likely due to the difference in mouth sizes), but the sims do suggest that there should be a difference.
 
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