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Post by fredygump on Aug 14, 2023 20:36:57 GMT -5
I have the XPA Gen 3 configured for 6-1S (8 channels), and I am using it to power a pair of 4 way active speakers.
The speaker design is like a smaller Genelec 8381A, so full range down to 20hz, with an emphasis on large woofers and subwoofers.
I've set myself a target of a peak SPL capability of 110dB (at listening position), to allow accurate reproduction of transients. To achieve this 110dB goal, I need the following power for each speaker:
Sub = 450 watts (4 ohms)
Woofer = 250 watts (4 ohms)
Mid = 150 watts (8 ohms)
Horn = 60 watts (8 ohms)
So call it 900 watts per speaker. 1800 for both speakers. (Of course this is the instantaneous peak, not continuous.)
Should this be manageable/ safe for the XPA amp? I'm asking because the specs are a little vague. The manual says the rating of continuous 490 watts into 4 ohms with 2 channels driven is representitive of what to expect with multiple channels driven, playing music content.
I'm thinking it'll be just fine, but the engineering part of my brain wants data!
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Post by AudioHTIT on Aug 15, 2023 13:25:49 GMT -5
I have the XPA Gen 3 configured for 6-1S (8 channels), and I am using it to power a pair of 4 way active speakers. The speaker design is like a smaller Genelec 8381A, so full range down to 20hz, with an emphasis on large woofers and subwoofers.
I've set myself a target of a peak SPL capability of 110dB (at listening position), to allow accurate reproduction of transients. To achieve this 110dB goal, I need the following power for each speaker: Sub = 450 watts (4 ohms)
Woofer = 250 watts (4 ohms)
Mid = 150 watts (8 ohms)
Horn = 60 watts (8 ohms)
So call it 900 watts per speaker. 1800 for both speakers. (Of course this is the instantaneous peak, not continuous.)
Should this be manageable/ safe for the XPA amp? I'm asking because the specs are a little vague. The manual says the rating of continuous 490 watts into 4 ohms with 2 channels driven is representitive of what to expect with multiple channels driven, playing music content.
I'm thinking it'll be just fine, but the engineering part of my brain wants data!
My thought is also that you'll be fine, but not sure I can supply all the data. I didn't look up your speakers, but am slightly confused by the term active speaker as to me that means they have amps built in. But no matter, if you start with the XPA-7G3, it will deliver 200 WPC ACD @ 8 ohms, so you have a total of 1400 watts continuous power -- the theoretical limit of a 120V/15A circuit would be 1800W, but of course there's power supply efficiency taking that number down, and storage -- giving you higher peaks. So we're asking if we can get from 1400 to 1800 (~28%) with some lower impedance and peak power storage? Seems possible, maybe even reasonable, but that's about as far as I can take it. |
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Post by fredygump on Aug 15, 2023 16:44:20 GMT -5
Thanks. I'm noticing the AC plug socket on my amp is labeled 20 amps. So that would indicate 2,400 watt input. I also found one place where they say the switching power supply is rated at 3kw.
In this case, "active" is just referring to the active crossovers (pre-amplification). I can think of a few systems that have active crossovers and have an external amplifier, but I agree most "active" speakers are like studio monitor speakers that have built in amplifiers.
I suppose it is possible to make a speaker with a built in amp, but with passive crossovers, and be called an "active" speaker?
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Post by AudioHTIT on Aug 15, 2023 17:07:19 GMT -5
Thanks. I'm noticing the AC plug socket on my amp is labeled 20 amps. So that would indicate 2,400 watt input. I also found one place where they say the switching power supply is rated at 3kw.
In this case, "active" is just referring to the active crossovers (pre-amplification). I can think of a few systems that have active crossovers and have an external amplifier, but I agree most "active" speakers are like studio monitor speakers that have built in amplifiers.
I suppose it is possible to make a speaker with a built in amp, but with passive crossovers, and be called an "active" speaker?
Ah, active crossover, got it, that’s the way to go! But yes, a speaker with built in amps (like the Emotiva AM5S I use on the desktop) would be referred to as active speakers, and in most cases would have active crossovers, but I suppose they might still be called active even with passive crossover. 🧐 I don’t think I’ve seen an XPA amp with a 20 amp socket (pretty sure neither my XPA-7 G2 or G3 had one), but if so that would indicate it could consume up to 2400W given the right power supply. A 20A socket would have horizontal blades. |
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Post by fredygump on Aug 15, 2023 21:35:38 GMT -5
Ah, active crossover, got it, that’s the way to go! But yes, a speaker with built in amps (like the Emotiva AM5S I use on the desktop) would be referred to as active speakers, and in most cases would have active crossovers, but I suppose they might still be called active even with passive crossover. 🧐 I don’t think I’ve seen an XPA amp with a 20 amp socket (pretty sure neither my XPA-7 G2 or G3 had one), but if so that would indicate it could consume up to 2400W given the right power supply. A 20A socket would have horizontal blades.
Here's a photo! (Sorry, dusty...)
The wall plug on the power cord is a 15A plug, but the socket in the amp says 20A. (I didn't unplug the cord from the amp to see if the socket in the amp is a 20A...
It's worth noting that a 15 amp breaker or fuse doesn't trip instantly at 15 amps. There are ratings for amperage and duration that result in a breaker or fuse tripping. So you can get 20 amps over a 15 amp circuit no problem, but for a short duration.
But yeah, more questions than answers.
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Post by AudioHTIT on Aug 16, 2023 0:24:26 GMT -5
Ah, active crossover, got it, that’s the way to go! But yes, a speaker with built in amps (like the Emotiva AM5S I use on the desktop) would be referred to as active speakers, and in most cases would have active crossovers, but I suppose they might still be called active even with passive crossover. 🧐 I don’t think I’ve seen an XPA amp with a 20 amp socket (pretty sure neither my XPA-7 G2 or G3 had one), but if so that would indicate it could consume up to 2400W given the right power supply. A 20A socket would have horizontal blades. Here's a photo! (Sorry, dusty...) The wall plug on the power cord is a 15A plug, but the socket in the amp says 20A. (I didn't unplug the cord from the amp to see if the socket in the amp is a 20A... It's worth noting that a 15 amp breaker or fuse doesn't trip instantly at 15 amps. There are ratings for amperage and duration that result in a breaker or fuse tripping. So you can get 20 amps over a 15 amp circuit no problem, but for a short duration.
But yeah, more questions than answers.
A 20A grounded socket would look like this (when in the horizontal position)  A 15A grounded socket would look like this (when in the horizontal position)  This photo of an XPA backside shows what looks like a 15A ungrounded socket (2 prong) which is I believe standard on all XPAs (despite the 20A label which might be for the circuit breaker). The socket (the weakest link) will be the determining factor, even if everything else was 20A. The specs only specify a voltage requirement, and this amp will run on anything from 100 to 250V so the power could theoretically increase with higher voltages, without exceeding 15A. Maybe KeithL can clarify the label.  |
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Post by leonski on Aug 16, 2023 1:27:54 GMT -5
Thanks. I'm noticing the AC plug socket on my amp is labeled 20 amps. So that would indicate 2,400 watt input. I also found one place where they say the switching power supply is rated at 3kw.
In this case, "active" is just referring to the active crossovers (pre-amplification). I can think of a few systems that have active crossovers and have an external amplifier, but I agree most "active" speakers are like studio monitor speakers that have built in amplifiers.
I suppose it is possible to make a speaker with a built in amp, but with passive crossovers, and be called an "active" speaker?
Ah, active crossover, got it, that’s the way to go! But yes, a speaker with built in amps (like the Emotiva AM5S I use on the desktop) would be referred to as active speakers, and in most cases would have active crossovers, but I suppose they might still be called active even with passive crossover. 🧐 I don’t think I’ve seen an XPA amp with a 20 amp socket (pretty sure neither my XPA-7 G2 or G3 had one), but if so that would indicate it could consume up to 2400W given the right power supply. A 20A socket would have horizontal blades. I think a 20 amp socket will have one 'T-Shaped' and one blade up/down.......So it's gonna be OK with double paralled blades of a 15 amp AND the 20 amp which is 2 blades at RIGHT ANGLES..... Ground in either case is the same. 20 amps at 120 v is 2400 watts.....but that is short time period.....And it's the same for 15 amp / 120v which is 1800 watts short term. I think the DERATE long time period would be 20%? If curious, talk to an electrician. All sorts of rules apply..... I don't know that 'peak power' to a speaker would be a problem......But I'd get clear on just WHAT was required to get to maximum power on the amplifier.....If it has a 20 amp setup? Make sure the power cord is 12ga or 10ga. And that EMO didn't 'cut corners' by supplying a 14ga cord. At least one of the early XP  mono amps required a 20 amp service to reach maximum power. All those poor schleps who put a pair of 'em on a single 15 amp service along with the rest of the HT system were wasting money.....But didn't seem to care. I had LOTS of discussions with people pointing out that their 600 a side amps would NEVER get that power wired the way which was very common.... The IEC connector .....on chassis.....is as AUDIO indicates...... Attachments:
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Post by leonski on Aug 16, 2023 1:47:57 GMT -5
I just looked at a couple backside images of EMO amps.
None had 20 amp IEC chassis sockets......All were configured for 15 amp service.....which probably only requires a 14ga cord......
I think the 3kw PS claim is a little......IFFY.......First? You can't get that out of a household outlet.....unless it's the one you use to
charge your EV.
Second? 3kw is like......100v at 30 amps. I'm disregarding normal losses which you can see expressed as how warm something runs....
Short time period? Just how short? And what is the voltage and current under those conditions.....?
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Post by fredygump on Aug 16, 2023 7:04:44 GMT -5
I just looked at a couple backside images of EMO amps. None had 20 amp IEC chassis sockets......All were configured for 15 amp service.....which probably only requires a 14ga cord...... I think the 3kw PS claim is a little......IFFY.......First? You can't get that out of a household outlet.....unless it's the one you use to charge your EV. Second? 3kw is like......100v at 30 amps. I'm disregarding normal losses which you can see expressed as how warm something runs.... Short time period? Just how short? And what is the voltage and current under those conditions.....? I'm not finding the chart I was looking for, but the takeaway is that the breaker (or fuse) is designed to protect the wiring in the house. So a way to think about it is the breaker will trip before the wiring gets too hot.
I've seen discussions about apparently under sized fuses in devices...which is done to account for the "blow rating" of the fuse vs the continuous current rating. So it is just an interesting quirk in how electronics work.
But yeah, I don't know why the label says 20 amps when it is a 15 amp cord and socket.... And there is only 1 place where you can find them give the 3K power supply capacity. Everywhere else they say it is over sized.
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Post by leonski on Aug 16, 2023 16:18:03 GMT -5
House wiring should be protected by the breaker in the box. Breaker / circuit wire size are to code. IOW? No 10ga on a circuit with a 15amp breaker.
And YES, for absolute sure. A 15 amp breaker OR fuse doesn't pop instantly at 15.01 amps but will last a LONG time. Higher over rate is quicker pop.
You can find such a table at LITTLEFUSE which has time / current curves.....
Wiring / with BREAKER in house is maximum rating but has 'long term' derate of IIRC.....20%.
I know cross country power lines are derated in the Heat Of Summer......Do NOT forget that as temp rises, so too, does the resistivity of the wire.
You see this in speaker voice coils, too......
Again, just my opinion, but If I were doing a clean sheet design? A couple dedicated 20 amp circuits for listening room. I use one 20 for just amps and sub.
If I was starting over, another circuit would be assigned TV, PRE, Game system and 'other'......
My house has only a 100 amp service which is marginal these days. I doubt I could add a high-power EV charging circuit without ending up using CANDLES
and a wood burning fireplace........And a charcoal grill for cooking.....
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Post by fredygump on Aug 16, 2023 16:29:47 GMT -5
House wiring should be protected by the breaker in the box. Breaker / circuit wire size are to code. IOW? No 10ga on a circuit with a 15amp breaker. And YES, for absolute sure. A 15 amp breaker OR fuse doesn't pop instantly at 15.01 amps but will last a LONG time. Higher over rate is quicker pop. You can find such a table at LITTLEFUSE which has time / current curves..... Wiring / with BREAKER in house is maximum rating but has 'long term' derate of IIRC.....20%. I know cross country power lines are derated in the Heat Of Summer......Do NOT forget that as temp rises, so too, does the resistivity of the wire. You see this in speaker voice coils, too...... Again, just my opinion, but If I were doing a clean sheet design? A couple dedicated 20 amp circuits for listening room. I use one 20 for just amps and sub. If I was starting over, another circuit would be assigned TV, PRE, Game system and 'other'...... My house has only a 100 amp service which is marginal these days. I doubt I could add a high-power EV charging circuit without ending up using CANDLES and a wood burning fireplace........And a charcoal grill for cooking..... Lol! A couple years ago I upgraded my house electrical. I still had fuses... Now I have 100A service in my house, and 200A to my garage. Don't judge; we all have our own priorities!
But yes, dedicated circuits for audio is a good idea, especially in pro audio. Houses probably don't have this problem, but sharing a common ground on all your equipment is another thing to look out for.
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Post by AudioHTIT on Aug 16, 2023 16:53:48 GMT -5
tHouse wiring should be protected by the breaker in the box. Breaker / circuit wire size are to code. IOW? No 10ga on a circuit with a 15amp breaker. … I may be having trouble with your nomenclature, but if you’re saying #10AWG on a 15A circuit, the wire would be way oversized, but legal, the breaker would trip first. Normally you’d use #14AWG on a 15A circuit, and #10 on a 30A circuit. |
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Post by SteveH on Aug 16, 2023 20:25:48 GMT -5
tHouse wiring should be protected by the breaker in the box. Breaker / circuit wire size are to code. IOW? No 10ga on a circuit with a 15amp breaker. … I may be having trouble with your nomenclature, but if you’re saying #10AWG on a 15A circuit, the wire would be way oversized, but legal, the breaker would trip first. Normally you’d use #14AWG on a 15A circuit, and #10 on a 30A circuit. A few years ago, I added six dedicated 20A circuits for my new Emotiva amplifiers. My branch circuits were 80 feet and to keep the voltage drop to less that 3% per the NEC, I had to use 10 AWG and this gave me a 2.7% voltage drop. My AHJ told me I was absolutely nuts for running 10 AWG, that I should be using 12 AWG. I told him the voltage drop math said 12 AWG was too small and he said "Meh, I would use 12 AWG anyway." If fredygump uses 10 AWG for his 15 amp circuits (which is legal as AudioHTIT stated), he will definitely have a very stiff AC power source! It will make it very easy to upgrade to 20 amp service later. |
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Post by leonski on Aug 16, 2023 20:29:30 GMT -5
Right.....my bad...... Wire must exceed breaker in 'capacity'......I should have written something like......'No 14ga on a 20 amp breaker....' In that case no meaningful overcurrent protection provided by the breaker.... except possibly in the case of dead short which should 'instantly' trip.......If you are trying something with 16 or 17 amps the wire may give up first..... My house is a good example. Kitchen SHOULD have had a 20 amp to where the Microwave would go but is only a 15.....with 14ga. And to Freddy? I'm a big fan of plenty of potential current to the largest of amplifiers. I got off the boat years ago when people were big fans of the XPA-1 or XPR-1 or whateve the BIG mono amp was that would have been best with a 20 amp service. It even said so in the specs somewhere. But many users seemed happy with a pair of 'em on a 15 amp service.....but never tried to 'tap' the full potential..... It gets into a big and protracted arguement, but for those happy running 600 watts (potential) per 96db sensitive speaker? Have fun! |
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Post by SteveH on Aug 16, 2023 21:15:48 GMT -5
But yes, dedicated circuits for audio is a good idea, especially in pro audio. Houses probably don't have this problem, but sharing a common ground on all your equipment is another thing to look out for.
Sharing a common ground is a wonderful thing, it eliminates those nasty ground loops. I had a 60Hz hum in my audio/video gear and it drove me nuts. For the money I have invested in my system, there should be no humming, no humming allowed! Long story short, the cable TV ground at the ground rod was poorly connected, very corroded and the two splitters in the attic were not grounded to the house electrical. Once I grounded the splitters and reworked the ground rod, all of the grounds were now at the same potential and the system became silent. |
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Post by Boomzilla on Aug 17, 2023 6:39:45 GMT -5
The average audio listener uses <1 watt during listening. But the average movie listener wants 110 decibels at the listening position. Why? That movie listener is so deaf from listening at that SPL that he NEEDS that volume to hear his movie.
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Post by 405x5 on Aug 17, 2023 6:54:04 GMT -5
I have the XPA Gen 3 configured for 6-1S (8 channels), and I am using it to power a pair of 4 way active speakers.
The speaker design is like a smaller Genelec 8381A, so full range down to 20hz, with an emphasis on large woofers and subwoofers.
I've set myself a target of a peak SPL capability of 110dB (at listening position), to allow accurate reproduction of transients. To achieve this 110dB goal, I need the following power for each speaker:
Sub = 450 watts (4 ohms)
Woofer = 250 watts (4 ohms)
Mid = 150 watts (8 ohms)
Horn = 60 watts (8 ohms)
So call it 900 watts per speaker. 1800 for both speakers. (Of course this is the instantaneous peak, not continuous.)
Should this be manageable/ safe for the XPA amp? I'm asking because the specs are a little vague. The manual says the rating of continuous 490 watts into 4 ohms with 2 channels driven is representitive of what to expect with multiple channels driven, playing music content.
I'm thinking it'll be just fine, but the engineering part of my brain wants data!
Why no make and model of the speaker you’re using sure as heck that would answer a lot of questions |
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Post by 405x5 on Aug 17, 2023 7:12:08 GMT -5
I had Loudspeakers that, in a typical listening room, could generate 100 DB using only a 30 W per channel amplifier. An example meant to point out that the Loudspeaker specifications are more important for getting there than the amplifier specs. though of course both are needed.
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Post by AudioHTIT on Aug 17, 2023 9:37:54 GMT -5
I have the XPA Gen 3 configured for 6-1S (8 channels), and I am using it to power a pair of 4 way active speakers. The speaker design is like a smaller Genelec 8381A, so full range down to 20hz, with an emphasis on large woofers and subwoofers.
I've set myself a target of a peak SPL capability of 110dB (at listening position), to allow accurate reproduction of transients. To achieve this 110dB goal, I need the following power for each speaker: Sub = 450 watts (4 ohms)
Woofer = 250 watts (4 ohms)
Mid = 150 watts (8 ohms)
Horn = 60 watts (8 ohms)
So call it 900 watts per speaker. 1800 for both speakers. (Of course this is the instantaneous peak, not continuous.)
Should this be manageable/ safe for the XPA amp? I'm asking because the specs are a little vague. The manual says the rating of continuous 490 watts into 4 ohms with 2 channels driven is representitive of what to expect with multiple channels driven, playing music content.
I'm thinking it'll be just fine, but the engineering part of my brain wants data!
Why no make and model of the speaker you’re using sure as heck that would answer a lot of questions He seems to have already done that math, his question is about power, not decibels. I actually think doing the math on a quad amped custom speaker would not be trivial, and would probably bring more questions than it answers. |
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Post by 405x5 on Aug 17, 2023 10:31:34 GMT -5
Starting to get interesting?  |
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mono amps required a 20 amp service to reach maximum power. All those poor schleps who put a pair of 'em on a single 15 amp service along with the rest of the HT system were wasting money.....But didn't seem to care. I had LOTS
