[mrzok]

I have an original VMPS larger subwoofer, bought in 1988, and upgraded with mega woofers in maybe 2000 or so. I also added a plate amp.

I've never upgraded the PR, so I started looking at a TC Sounds solution. I ran some numbers through a speaker design tool, modeling it as a 145L box with two 15" TC Sounds drivers and a 15" PR (the modeling software only supports one type of speaker, but with multiple instances).

What I found surprised me. As a straight install, the model shows a 6 - 9db rolloff from about 50Hz down to 17Hz. This clearly isn't the kind of performance we expect from the larger subwoofer. The model said I would need about 1kg of washers on the PR, and 150g of added weight on the driver cones, to get a reasonably flat response.

Anybody done a TC Sounds upgrade, AM I missing something?

   

[PMAT]

Put this in the enclosures circle.

[WireNut]

Try modeling them in a push-pull or isobaric box if your software will allow. Should go lower but you may loose 3bd of efficiency compared to both 15" facing forward.

 

[opnly bafld]

Does your modeling include room gain?

[John Casler]

I have an original VMPS larger subwoofer, bought in 1988, and upgraded with mega woofers in maybe 2000 or so. I also added a plate amp.

I've never upgraded the PR, so I started looking at a TC Sounds solution. I ran some numbers through a speaker design tool, modeling it as a 145L box with two 15" TC Sounds drivers and a 15" PR (the modeling software only supports one type of speaker, but with multiple instances).

What I found surprised me. As a straight install, the model shows a 6 - 9db rolloff from about 50Hz down to 17Hz. This clearly isn't the kind of performance we expect from the larger subwoofer. The model said I would need about 1kg of washers on the PR, and 150g of added weight on the driver cones, to get a reasonably flat response.

Anybody done a TC Sounds upgrade, AM I missing something?

 

I would advise against going TC Sounds,  except for the Passive Radiator in a LARGER.  Brian tried to add the TC Sounds drivers and as it turned out the only cabinets it worked well in was the VSS and the VLA.

The Tall Boy LARGER would likely be the least satisfactory without significant modification and bracing.

Plus Brian did not follow the traditional "modeling" for subs and as most know was able to become "KNOWN" for his subs and their performance.

Rather than ruin your LARGER, I might suggest simply replacing your present PR with the new ULTRA Passive ($115 plus shipping).

It is 99% of the more expensive TC Sounds in this application, and you don't sacrifice the musicality, which is why the LARGER was built.

[Conradicles]

Good advice John.

[mrzok]

Thanks, everybody. John's post pretty much confirms what the model tells me - don't try TC Sounds in the old Larger cabinet, the results won't be good.