How would one go about using 2 bass drivers in a TL or ML-TQWT? Does one need to change the design or can you design for a single driver and just add the second one under the first in the same box?
The reason for asking is I was thinking along the lines off a slim floor standing speaker for WAF, thus needing small drivers. I don't think a single 5" or 6.5" driver would be enough, hence the thought of using a folded TL and thinking by adding another driver I can increase the surface area.
Both drivers will be the bass section in a 3-way
The reason for asking is I was thinking along the lines off a slim floor standing speaker for WAF, thus needing small drivers. I don't think a single 5" or 6.5" driver would be enough, hence the thought of using a folded TL and thinking by adding another driver I can increase the surface area.
Both drivers will be the bass section in a 3-way
@ sreten, thanks for the info, as I read it I clicked that basically the driver parameters of importance for a TL remains the same, but with a larger cone area. Makes perfect sense.
@jerryo, I have considered an isobaric setup, but using larger side firing drivers and getting a smaller enclosure because of the isobaric setup. I have used it before with reasonable succes, getting a smallish box to play down to 50Hz from 75Hz.
@jerryo, I have considered an isobaric setup, but using larger side firing drivers and getting a smaller enclosure because of the isobaric setup. I have used it before with reasonable succes, getting a smallish box to play down to 50Hz from 75Hz.
You will get claims and counter claims about the whole isobaric thing, some in favour and some against. Whether it is worth the extra drivers and power requirements and reduced efficiency is probably a personal choice! A search will reveal the opinions on the matter.
"I do like the bass from my Linn Isobarik's however"
"I do like the bass from my Linn Isobarik's however"
So basically I would end up with a bigger box if I use 2 drivers instead of 1 box?
Hi,
Inevitably a box with two drivers will be twice as big as one with one.
With twin drivers you can make the box narrower and deeper than
using a single larger driver.
rgds, sreten.
Hi,
Isobaric is simply a compound driver made from two drivers. The resultant
parameters of the compound driver can often be found in other single drivers.
e.g. the parameters of two 8 ohm 6.5" bassmids used isobarically become more
similar to the parameters of a 4 ohm 6.5" designed specifically as a subwoofer.
It works, but there is no magic, which why they are quite rare.
Often good for repurposing cheaper drivers into something they were
not really designed for, and the typical clamshell arrangement will
cancel any magnetic and suspension assymetry of cheaper drivers.
Compared to one driver, two isobaric have :
Double the cone mass, half the Vas and hence the same Fs.
Half the impedance (or double), the efficiency is halved.
The same sensitivity for parallel and - 6dB for series.
The same maximum SPL.
Essentially your halving box size at the cost of half the efficiency.
rgds, sreten.
It's worked for me. Without it, making [ML] TLs with some of the ultra high Vas drivers I've used [~15 -30+ ft^3] would have resulted in unacceptably large cabs with just one woofer and due to their typically low linear excursion capability, dual drivers/channel were often required anyway to get sufficient dynamic headroom down low.
GM
Hi,
Clearly isobaric works for silly Vas drivers, your just creating a compound
driver with more sensible parameters. That does not validate isobaric as
a principle that works, its more a useful technique for parameter shifts.
You can always build a single driver equivalent to a compound pair.
rgds, sreten.
Clearly isobaric works for silly Vas drivers, your just creating a compound
driver with more sensible parameters. That does not validate isobaric as
a principle that works, its more a useful technique for parameter shifts.
You can always build a single driver equivalent to a compound pair.
rgds, sreten.
Last edited:
True and it worked as predicted, so if this doesn't validate the principle, then what does?
Well, manufacturers can, but it's beyond the capabilities of the vast majority of DIYers, so we work with what's available and when high acoustical efficiency combined with a low tuning is a performance goal, then 'silly Vas' drivers is the way to go if a lot of low efficiency drivers and the high power required to drive them isn't an option for whatever reason.
GM
Well, manufacturers can, but it's beyond the capabilities of the vast majority of DIYers, so we work with what's available and when high acoustical efficiency combined with a low tuning is a performance goal, then 'silly Vas' drivers is the way to go if a lot of low efficiency drivers and the high power required to drive them isn't an option for whatever reason.
GM
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.