TOPIC:

Hi,
Bass produced by transmission lines can be a bit uneven. Since that bass is not produced directly by a cone moving in and out but instead (if I understand correctly) through the combination of drive unit and transmission line, is it still possible to correct it?

asx77 wrote:

Hi,
Bass produced by transmission lines can be a bit uneven. Since that bass is not produced directly by a cone moving in and out but instead (if I understand correctly) through the combination of drive unit and transmission line, is it still possible to correct it?

Yes, it makes no difference.

It's the contribution of the room to the bass response that is overwhelmingly being compensated for by the way.

Ok so it can be corrected as if it were a normal drive unit? I though TLs tend to be tuned to create a certain frequencies only.

Appreciate that the Room is the biggest problem but if you had a perfect room and imperfect speaker than Dirac would correct your speaker right?

Unless you have some huge bass traps that you haven't mentioned your room will not be remotely perfect.

If it helps I'll say my main speakers are a transmission line design (Meadowlark Shearwater Hot Rods) and I also own a sealed subwoofer (PSA S1510). The frequency response of both are dominated by room modes when my room has no bass traps in it.

No, not suggesting my room is perfect. Just saying in principle Dirac is correcting everything. Source, Amp, Speakers, Room and in a situation where the room may be perfect it will correct the rest. As you point out, in reality the biggest influence on a non-flat response will be the room. For the record, I don’t have bass traps!

Have you got before and after plots of the overall response that you could share?

The reason I ask about correcting transmission line bass is I’ve my eye on PMC speakers for my follow on upgrade and all their speakers use an ATL.

asx77 wrote:

No, not suggesting my room is perfect. Just saying in principle Dirac is correcting everything. Source, Amp, Speakers, Room and in a situation where the room may be perfect it will correct the rest. As you point out, in reality the biggest influence on a non-flat response will be the room. For the record, I don’t have bass traps!

Have you got before and after plots of the overall response that you could share?

The reason I ask about correcting transmission line bass is I’ve my eye on PMC speakers for my follow on upgrade and all their speakers use an ATL.

Please don't think transmission line speakers are somehow so flawed that they need correction. They're not.

Hi,
No I wouldn’t be considering a pair if I did. I think we’ve got off track too. Dirac can only compensate for a room by changing the signal sent to the speaker. My concern was if I went for a pair of speakers that used a TL, could Dirac change the airflow as effectively as it can adjust a driver.

Consider two different routes to producing 40-70Hz bass. (1) Sealed subwoofer (2) Transmission line.

Number 1 is surely easier to adjust, whereas 2 is using a combination of speaker and tuned (to perhaps to a narrow frequency band) port. I can’t get my head around the mechanics of adjusting no.2

asx77 wrote:

Hi,
No I wouldn’t be considering a pair if I did. I think we’ve got off track too. Dirac can only compensate for a room by changing the signal sent to the speaker. My concern was if I went for a pair of speakers that used a TL, could Dirac change the airflow as effectively as it can adjust a driver.

Consider two different routes to producing 40-70Hz bass. (1) Sealed subwoofer (2) Transmission line.

Number 1 is surely easier to adjust, whereas 2 is using a combination of speaker and tuned (to perhaps to a narrow frequency band) port. I can’t get my head around the mechanics of adjusting no.2

As per my original post - it makes no difference.

In case it helps, let me say that what sound comes out of the end of a transmission line, or indeed a port, is 100% determined by the motion of the driver(s).