Adapting small drivers to a TL

[pjblakey]

I have a pair of Royd Herald stand mount speakers (0.23cu.ft vented box tuned to 43Hz) and I am considering building a pair of floor standing transmission line cabinets(I enjoy woodwork!) to house the same drivers.
Is it correct to assume that I should make the length of line based on the 43Hz frequency employed with the Heralds, or are there other considerations?
I'll probably go active with the new speakers, so a passive crossover will be avoided.

Peter

 

[planet10]

You need to start by measuring the drivers.

dave

 

[pjblakey]

Thanks for the response, but I don't have the wherewithall or equipment to measure driver parameters, hence my question in my previous post. In different words, "Will a driver that works well in a bass reflex box tuned to 43Hz work as well in a TL enclosure tuned to the same frequency?"

Peter

 

[planet10]

Maybe, maybe not. To design a proper TL you need the driver parameters (like any other box)

The Subwoofer DIY Page - Measurements

dave

 

[GM]

"Will a driver that works well in a bass reflex box tuned to 43Hz work as well in a TL enclosure tuned to the same frequency?"

As a general rule, no unless it's a high ratio reverse taper TL (TQWT) which in essence morphs the box/port volumes into one continuous tuned pipe. Unfortunately, a 0.23 ft^3 cab for a ~5" driver implies it has specs that will make it severely under-damped in one, so will probably require an excessive amount of stuffing to tame it which some folks find unacceptable.

If you just want to experiment a bit, make a ~52" high rectangular tube with the same external width, depth dims as the existing cabs and place the driver ~18" down from the top. Experiment with the gap height between the open bottom and floor to get the strongest sounding bass response (it's typically quite 'boomy'/'bloated'), then stuff to 'taste' with the highest concentration at the top to quell its strongest pipe modes and somewhat less density down the rest of the pipe to finish smoothing it out.

GM

 

[pjblakey]

Thank you, Planet10 and GM. Experimentation is in order. Will report back later.

 

[PeteMcK]

re:'I don't have the wherewithall or equipment to measure driver parameters' - yes you do, well, almost...To measure drivers: Download ARTA: ARTA ARTA Download, Make this simple jig: ARTA Jig - AudioBlog: A simple loudspeaker measurement jig for ARTA