Just wanted to let you guys who are building RLp15 ported subs with Behringer EP2500 know that how you wire the driver will affect how it responds to the amount of power you feed it. Since this is a popular design, I wanted to give an update based on measured parameters Mike from SS gave me. FR basically stays about the same, but how power relates to excursion changes. If we take a look at a design, say ~325 liters and tuned low, and wire the driver in parallel as opposed to feeding each voice coil from it's own amp channel, you use up a lot more excursion in certain frequency regions, as sensitivity changes. Please see attahced.

The red line represents wiring in parallel - the white line is with each coil being fed from its own amp channel, and thus is able to even get away with slightly lower tuning while still staying amp limited. The yellow line is wiring in parallel based on the normal driver parameters, so you can see it gives a false sense of protection, even though it is exceeding excursion limits to begin with. The real paremeters show that going with parallel wiring will make you very susceptable to bottoming the driver in certain frequency ranges above tuning, as can be seen.

Anyway, just an update and a heads up. Logic should tell most of you this would have been the case, but...well, you never know ;)

So, are ya going to share the T/S numbers?

I must be tired...how does this apply? Are you to wired this in parallel to do this?

When I model the RLp15D4, I have it so the two coils are in series and then parallel a pair.

So, what Im seeing in Unibox is accurate I hope? These may be THE subs I end up getting...

Nevermind, I found them in the "other" thread.

PARALLEL

--------------------------------------------------------------------------------

Qts - 0.417
Qes - 0.450
Qms - 5.560
Fs - 22.771 Hz
Res - 1.54 Ohm
Ls - 1.001 mH
Lp - 2.541 mH
Rp - 1.949 Ohm
Dia - 330 m
(% shift) - 24.5%
Vas - 173.5 L
Mms - 289.1 g
Cms - 168.9 m/N
BL - 11.89 T*m
n0 - 437.6 m
Spl/Sens - 88.41 dB


Scott, I am referring to the D4, which has two 4ohm voice coils. The wiring becomes a bit more tricky than with the D2 - D2 is easy, just wire them in series to create a 4ohm load. With the D4, you can either feed each voice coil off it's own amp chanel (preferred), wire the coils in series for an 8ohm load (tough because you need a REALLY powerful amp), or wire the coils in parallel to create a 2ohm load (which affects low end sensitivity and will slightly increase distortion). Basically these parallel parameters will allow for a more accurate simulation if you choose to wire the driver in parallel - the regular parameters don't reflect the shift in sensitivity.

So, wiring in parallel drops the Fs? Never knew such a thing could result from wiring.

So, the best way for the D4 is to feed each VC to it's own channel on the EP2500 and wiring it for a 2ohm load can possibly bottom the driver. Got it.

So, what Im seeing in Unibox is accurate I hope? These may be THE subs I end up getting...Unibox is very accurate, we've done comparisons between Unibox and LspCAD they give similar results.

Mkay...

Steve - when (more like, if) I order a RLp15d4...it would be a pair. So two together would be 4-ohm. Perfect for a bridged 2500. :D

Umm, or you could just get two D2 and wire each off its own amp channel? I'd recommend going this way, as the D2 has a lower Q and the sub will be more damped. Also, the D2 requires a smaller enclosure and will use slightly less excursion with the same amount of power.

Hmmm, I like the way the D4's model for an implementation that I'd do. Plus, D2's are still outta stock, IIRC.

I also like the idea of having an alignment I like where the port could fit. I can't get the port to fit as well on a similar alignment with the D2's.

I think I'll stick with the D4's.

EDIT: Wait a minute! Steve, dude, did you just say I should try a woofer in a smaller box? You know who you're talking to, right? ;)

Heheh, just read that thread where we had that 3000+ liter LMS4k...that thing was huge!

Its funny, Steve, that you mention dropping the size of the enclosure. Well, funny after just reading that thread, though.:D

PARALLEL

--------------------------------------------------------------------------------

Qts - 0.417
Qes - 0.450
Qms - 5.560
Fs - 22.771 Hz
Res - 1.54 Ohm
Ls - 1.001 mH
Lp - 2.541 mH
Rp - 1.949 Ohm
Dia - 330 m
(% shift) - 24.5%
Vas - 173.5 L
Mms - 289.1 g
Cms - 168.9 m/N
BL - 11.89 T*m
n0 - 437.6 m
Spl/Sens - 88.41 dB


Scott, I am referring to the D4, which has two 4ohm voice coils. The wiring becomes a bit more tricky than with the D2 - D2 is easy, just wire them in series to create a 4ohm load. With the D4, you can either feed each voice coil off it's own amp chanel (preferred), wire the coils in series for an 8ohm load (tough because you need a REALLY powerful amp), or wire the coils in parallel to create a 2ohm load (which affects low end sensitivity and will slightly increase distortion). Basically these parallel parameters will allow for a more accurate simulation if you choose to wire the driver in parallel - the regular parameters don't reflect the shift in sensitivity.

What's the Pe?