Community XLT-55 Replacements

[MomaDance22]

Hi everyone-

I am looking for replacement woofers for two Community XLT 55 cabinets I have. These cabinets are for low / mid bass reinforcement.

In doing research, I have read alot of good things about Eminence, but I am becoming confused on the proper way to size woofers to cabinet volume.

That said, the Lab 15's look to be too expensive for my budget, so I am leaning towards the Deltas but am not sure if I am on the right track.

Does anyone have experience replacing woofers in the XLT55 or similar volume cabinets?

Cheers
Moma

 

[Zwiller]

If blown see if you can get them reconed. Probably the cheapest move. Those are not really a sub in today's standards so if they are not mid bass cabs ditch them and look at some of the popular designs here. If gung ho about keeping and upgrading them, it's a matter of inputting the data of the cabinet into software and model it to see what drivers work. Take exterior measurements and deduct wood volume to calculate interior volume and then size the ports. If you post the measurements someone could run it for you.

 

[weltersys]

I am looking for replacement woofers for two Community XLT 55 cabinets I have. These cabinets are for low / mid bass reinforcement.

That said, the Lab 15's look to be too expensive for my budget, so I am leaning towards the Deltas but am not sure if I am on the right track.

Moma,

You get what you pay for, Lab 15 cost more because they have far more displacement capability than the Delta 15LFA, 11.8mm Xmax compared to only 4.8mm. Doubling displacement allows for 6 dB more low frequency output.
The Delta 15LFA also has a much larger VAS than the Lab 15, it would not have much LF output in a box as small as the XLT 55. That said, it would be much more sensitive in the mid bass (above 70 Hz) range.

The XLT 55 is approximately 5.7 cubic feet net,(2.85 per driver)with around 42 Hz Fb judging by the impedance minima. The Lab 15 would work pretty well in it with the existing tuning, with a bit of a bump around Fb compared to the simulation below.

Art

 

[Brian Steele]

That said, the Lab 15's look to be too expensive for my budget, so I am leaning towards the Deltas but am not sure if I am on the right track.

What exactly is your budget? There are number of 15" drivers that would work "well" in a cabinet that size, with what constitutes "well" being defined on how much you want to compromise between "loud" and "low".

Concerning the use of LAB15s, one way to look at the expected response of those drivers in that cabinet (as Art said in his message) is that they will have a bump around the resonance frequency. Another way to look at that response though is one that droops at higher frequencies after 42 Hz


FWIW, I'd be concerned if two 4" vents per driver would be enough to get the best out of a LAB15 before vent compression becomes significant, making that peak at 42 Hz much less of a peak.

 

[chris661]

FWIW, I'd be concerned if two 4" vents per driver would be enough to get the best out of a LAB15 before vent compression becomes significant, making that peak at 42 Hz much less of a peak.

+1.

I was getting 2dB of port compression with a slightly-tapering port that gets to 305cm^2 on a high-power 15" on the end of 90V sine tones. That's around double the area of a pair of 4" ports.

Given that, I'd be looking for something that gives a response that drops down towards the port tuning, so at least it can go loud in the >50Hz range and still do something at 40Hz.

Chris

 

[conanski]

These cabinets are for low / mid bass reinforcement.

This is the key point here, if these boxes are not being used as subwoofers then you don't want to install subwoofer drivers like the Lab15 in them, you want something similar to the original driver that is closer to an musical instrument driver. What bandwidth are these boxes covering? If it is something like 80-250hz then a driver like the KappaPro 15 would be a good choice.

 

[Brian Steele]

Given that, I'd be looking for something that gives a response that drops down towards the port tuning, so at least it can go loud in the >50Hz range and still do something at 40Hz.

Yup, good point. The sim shows a peak at or just above Fb with the Labs, but that peak is going to be much less of a peak at PA volumes, so you'd have sacrificed quite a bit of possible passband efficiency at PA levels by going with LABs in that box.


IMO vent compression might be one of those things that contributes to the "sound" of a vented sub, as many that I've seen use vents that definitely look a bit small for the driver. Of course, if you make the vent larger to reduce the compression effect, you're likely going to start encountering the impact of pipe resonances on the passband. May as well design the subwoofer with those in mind to take advantage of them (TLs and MLTLs), which is likely why I'l probably never design or build a bog-standard vented subwoofer again.