Has anyone compared a PL380 at 4 ohm stereo vs 2x PL340's bridged 4 ohm, on subs? I know what the spec sheets say, looking for an actual comparison.
QSC PL3 on subs
- Thread starter Caleb Dueck
- Start date
Re: QSC PL3 on subs
You know those PL340s will be seeing 2 ohms if you bridge them into 4, right?
Bennett "HATES bridged" Prescott
You know those PL340s will be seeing 2 ohms if you bridge them into 4, right?
Bennett "HATES bridged" Prescott
Re: QSC PL3 on subs
Yes, of course, hence the question. Applications are low-budget, where a FP14k won't fit. Rather than get a PL380 and PL340 to test first-hand, was wondering is someone else had these exact amps already.
Yes, of course, hence the question. Applications are low-budget, where a FP14k won't fit. Rather than get a PL380 and PL340 to test first-hand, was wondering is someone else had these exact amps already.
Re: QSC PL3 on subs
Since you have to buy twice as many smaller amps and then drive them harder, is there really a cost savings?
Since you have to buy twice as many smaller amps and then drive them harder, is there really a cost savings?
Re: QSC PL3 on subs
That's the question, mostly. A PL380 in stereo isn't quite enough output, a pair of PL340's -on paper- is enough. Does reality line up with paper numbers.
That's the question, mostly. A PL380 in stereo isn't quite enough output, a pair of PL340's -on paper- is enough. Does reality line up with paper numbers.
Re: QSC PL3 on subs
$500 more, double the rack space, nearly double the weight, running the amps at the edge of their capability, for a less than 3dB increase? Even on paper it wouldn't be worth it to me.
Mac
$500 more, double the rack space, nearly double the weight, running the amps at the edge of their capability, for a less than 3dB increase? Even on paper it wouldn't be worth it to me.
Mac
Re: QSC PL3 on subs
The PL380 has an amazing amount of voltage swing in bridged mode, but Bennett's right, in a perfect world you'd buy bigger amps that don't need to be run bridged. It's generally best to run amps at twice their lowest rated load impedance unless the mfg specifies the sweet spot for you such as Crown does for the ITech's.
Another downside that some folks mention is that bridged mode halves the nominal damping factor by doubling the amp output impedance. I think this reasoning is bogus because the standard damping factor equation is bogus. The truth is that the real electrical damping factor includes round-trip cable and voice coil resistances which makes the approx .02Ω impedance on each of the amp's positive output terminals a drop in the bucket.
If you want to experiment with bridging you can always do a one-sub shootout with the PL380 (I assume) you already have and see if bridged mode makes a significant difference or not. If you decide it's worth it, I'd use PL380's, not something smaller that will run closer to it's maximum output. Class D is a real advantage as well when you're driving an amp hard. You'll also need to provide a 30 amp supply for these things when bridged. If you find that the amp does not trip a 20 amp breaker in bridged mode, the sub is getting driven to its max with the PL380 in stereo mode.
The PL380 has an amazing amount of voltage swing in bridged mode, but Bennett's right, in a perfect world you'd buy bigger amps that don't need to be run bridged. It's generally best to run amps at twice their lowest rated load impedance unless the mfg specifies the sweet spot for you such as Crown does for the ITech's.
Another downside that some folks mention is that bridged mode halves the nominal damping factor by doubling the amp output impedance. I think this reasoning is bogus because the standard damping factor equation is bogus. The truth is that the real electrical damping factor includes round-trip cable and voice coil resistances which makes the approx .02Ω impedance on each of the amp's positive output terminals a drop in the bucket.
If you want to experiment with bridging you can always do a one-sub shootout with the PL380 (I assume) you already have and see if bridged mode makes a significant difference or not. If you decide it's worth it, I'd use PL380's, not something smaller that will run closer to it's maximum output. Class D is a real advantage as well when you're driving an amp hard. You'll also need to provide a 30 amp supply for these things when bridged. If you find that the amp does not trip a 20 amp breaker in bridged mode, the sub is getting driven to its max with the PL380 in stereo mode.
Re: QSC PL3 on subs
Looks like PL380's, for all the other reasons than straight power. Other than applications where there just aren't amps large enough (Danley J2's), bridging has never been the best option.
Looks like PL380's, for all the other reasons than straight power. Other than applications where there just aren't amps large enough (Danley J2's), bridging has never been the best option.
Re: QSC PL3 on subs
Yes I am well aware this information is not readily available.
As a matter of information-The Danley J2 can be ordered as a 3 way quad amped cabinet. 2x 3 ohm loads for the lows, 1x 4 ohm load mid and 1x 4 ohm load highs, OR the passive single channel 4 ohm version. It works well off of a single 4 channel Lab Gruppen 10K in the quad mode. We use a Lab 14K bridged when running it in passive single channel mode.
Yes I am well aware this information is not readily available.
Silas Pradetto
Graduate Student
Re: QSC PL3 on subs
I'd always go with the class D or I amp over a class AB or H amp because I feel that the bass is much tighter.
I'd always go with the class D or I amp over a class AB or H amp because I feel that the bass is much tighter.