Yamaha Professional Audio

[Verdinut]

One thing I've noticed because I use externally-powered subwoofers is that the Yamaha PX Class-D pro amps have High-Pass Filter down to 20Hz, whereas the Crown only goes down to 31Hz.

The QSC DCA (Digital Cinema Amplifiers) Series have a frequency response going below 20Hz, an advantage for listening to pipe organ music or movie sound effects, provided that you have the sub(s) that can handle and reproduce the infrasonic frequencies:

Frequency Response: 20 Hz- 20kHz ±0.15 dB (at 10 dB below rated output : -3 dB points: 5 Hz and 100 kHz)

 

[Out-Of-Phase]

QSC is another brand I've been looking at. Some critics says loud fans though.

 

[AcuDefTechGuy]

QSC is another brand I've been looking at. Some critics says loud fans though.

Yeah, I would stick to Class-D amps. Less heat, less need for fans.

 

[Verdinut]

QSC is another brand I've been looking at. Some critics says loud fans though.

The fans on the LIVE SOUND and some of the SYSTEMS series are really noisy, but the ones on the DCA amp series are a lot quieter.

I am using 3 DCA 1222s and 1 DCA 1824 on my HT system. Actually, the DCA 1222s are rather quiet and their noise is easily masked by the SPL coming out of the speakers. The DCA 1824 is a 4 channel amp in the same size chassis and is noisier because its fan has to keep 4 output stages cooler instead of 2.

Everything also depends on your sitting distance from the amps and the surroundings as well. I am sitting only six feet from them and I can hear them if there are no other noise from the kitchen refrigerator, the humidifier or the air conditioner. I live in a 3½ room apartment, so everything is close.

As far as heat is concerned with the DCA amps, with the variable speed fan there is no heat on top. Actually, they are designed to be stacked one on top of the other without spacing as with most pro audio gear. Also, if you are only using an average of a couple of watts for driving the speakers, the fan will run at a slow speed resulting in a quieter operation. On the other hand, if you drive to reference levels or louder, you will never have to worry about fan noise.

I am very happy with those amps and I intend to keep them. They are acoustically transparent and reliable:

https://www.qsc.com/cinema/products/power-amplifiers/dca-series/

 

[Out-Of-Phase]

They look good, I went to their website. It looks like they are a Class AB design.

 

[lovinthehd]

I wish all these pro amps have RACK mounts that are OPTIONAL.

How difficult can it be to let the consumers screw or unscrew those side rack mounts?

Then they'd be pro-sumer amps ? Why increase costs is probably one good reason...

 

[Verdinut]

They look good, I went to their website. It looks like they are a Class AB design.

All the DCA Series amps feature a switching power supply.

The DCA 1222 and the 1622 operate in Class AB whereas the more powerful units operate in a 2-step Class H configuration.

 

[Out-Of-Phase]

All the DCA Series amps feature a switching power supply.

The DCA 1222 and the 1622 operate in Class AB whereas the more powerful units operate in a 2-step Class H configuration.

Okay, thanks.

 

[AcuDefTechGuy]

Then they'd be pro-sumer amps ? Why increase costs is probably one good reason...

Making the rack mount a screw-on option, making it look prettier, promoting it as consumer amps, and adding a 12V-trigger would increase cost a little, but I think it might also increase sales.

 

[lovinthehd]

Making the rack mount a screw-on option, making it look prettier, promoting it as consumer amps, and adding a 12V-trigger would increase cost a little, but I think it might also increase sales.

Maybe. So much prejudice both aesthetically and "sound quality" wise in the "audiophile" world.....I don't even care about the ears on my XLS1500s, just doesn't mean much. Pretty is only so useful.

 

[highfigh]

Well, I said I "noticed" the HPF of 31 vs 20 Hz, not concerned.

Personally, I don't worry about having a HPF of "only" 31Hz either. I only care about sounds that I can hear, not feel.

These filters are not "brick walls", but setting the decibel slope to 36dB will cause a steeper drop-off closer to being a "brick wall" than a slope of 12dB.

We don't actually "hear" 31 OR 20 Hz, we sense them through bone conduction. In fact, if you have your hearing tested and one ear is clogged, they'll only test bone conduction and IIRC, that started at their minimum frequency and went up to 400Hz, but not higher. The nerves are stimulated, but not as much by moving the cilia.

 

[highfigh]

Maybe. So much prejudice both aesthetically and "sound quality" wise in the "audiophile" world.....I don't even care about the ears on my XLS1500s, just doesn't mean much. Pretty is only so useful.

Rack ears are more for using the available rack space more efficiently than anything else- there's no reason to use fixed shelves unless there's no way to attach rack ears in a non-consumer type of rack. Rack mounting also provides more stability for the rack WRT lateral movement.

 

[highfigh]

I wish all these pro amps have RACK mounts that are OPTIONAL.

How difficult can it be to let the consumers screw or unscrew those side rack mounts?

Consumers often can't wait to throw their boxes out, which usually contain the manual and accessories. Then, they whine when they can't find the ears and screws. Commercial/industrial installations are almost always in an equipment rack and there are many reasons for this- first, it's secure. Second, the rack is supposed to be grounded properly and third, the equipment's temperature needs to be maintained, to prevent thermal damage and/or intermittent shut-down. Pro amplifier spec sheets show the heat output in BTU, so the room can be vented or cooled according to the needs of the equipment. When you have a room filled with equipment rack that are at capacity, that room can be brutally hot. Also, in a situation like that, the cooler pieces are placed lower in the rack so they aren't overheated by the hotter ones.

If consumers want pro gear, they need to work with it as it comes, not wish for the manufacturers to cater to a small percentage of the market.

 

[AcuDefTechGuy]

If consumers want pro gear, they need to work with it as it comes, not wish for the manufacturers to cater to a small percentage of the market.

It wouldn’t be a small percentage if the manufacturers would cater to the consumers.

The reason it is still a small percentage is because the manufacturers don’t cater to the consumers.

 

[AcuDefTechGuy]

We don't actually "hear" 31 OR 20 Hz, we sense them through bone conduction. In fact, if you have your hearing tested and one ear is clogged, they'll only test bone conduction and IIRC, that started at their minimum frequency and went up to 400Hz, but not higher. The nerves are stimulated, but not as much by moving the cilia.

We can’t hear 31Hz?

I can easily hear the lowest note on my piano, which is 27.5 Hz.

But you’re saying that I’m not really “hearing” 27.5 Hz?

 

[highfigh]

We can’t hear 31Hz?

I can easily hear the lowest note on my piano, which is 27.5 Hz.

But you’re saying that I’m not really “hearing” 27.5 Hz?

We have the sensations, but the ears are too small to really capture the notes because of the short path and small outer ear. Wear ear plugs and thump your arms, knees, shoulders and you'll 'hear' the impact, but none of it will be high or midrange frequencies.

If you use RTA software or a phone app, you'll see that most of what comes from pressing the lowest notes on your piano aren't 27.5Hz- it's almost all harmonics. The only place you can pluck the note and hear the fundamental is at mid-span.

 

[highfigh]

It wouldn’t be a small percentage if the manufacturers would cater to the consumers.

The reason it is still a small percentage is because the manufacturers don’t cater to the consumers.

We already had a discussion about people not understanding specs and pro/commercial manufacturers don't want to spend more time on tech support than they have to. People don't like to read manuals as it is- should they buy more complex equipment and not read those manuals, too?

Consumers are drawn to gadgets, pros are drawn to performance and specs because the specs make it easier to choose the correct equipment for the job. How many consumers bother to think about the room's internal volume? Almost none. That's one reason they can't find speakers that work for them. The internal volume and distance to the listening position are two reasons people choose the wrong equipment, along with not understanding that if they never need to reach high SPL, high power isn't needed as long as the amplifier(s) have some amount of headroom.

 

[lovinthehd]

Rack ears are more for using the available rack space more efficiently than anything else- there's no reason to use fixed shelves unless there's no way to attach rack ears in a non-consumer type of rack. Rack mounting also provides more stability for the rack WRT lateral movement.

I understand the advantages of rack mounting and why a pro amp would assume the use of such. My comment was more about the consumer's tolerance of its existence, i.e. I don't care if they're present even if I'm not using them. The aesthetic has little impact.

 

[AcuDefTechGuy]

We have the sensations, but the ears are too small to really capture the notes because of the short path and small outer ear. Wear ear plugs and thump your arms, knees, shoulders and you'll 'hear' the impact, but none of it will be high or midrange frequencies.

If you use RTA software or a phone app, you'll see that most of what comes from pressing the lowest notes on your piano aren't 27.5Hz- it's almost all harmonics. The only place you can pluck the note and hear the fundamental is at mid-span.

Very interesting. All this time I thought we could actually hear things down to 20Hz.

Subwoofers that go down to 30Hz and HPF that goes down to 31Hz don't seem to bad then.

 

[highfigh]

Very interesting. All this time I thought we could actually hear things down to 20Hz.

Subwoofers that go down to 30Hz and HPF that goes down to 31Hz don't seem to bad then.

They may do that in their test facilities, but we often get the benefit of room gain, so the useful energy may go to 20Hz.

Remember the Bone Phone? It used bone conduction to fill in the low frequencies that were clearly missing when it was held in the open but when laid on the neck and shoulders, it sounded decent- good enough for some uses.

We called it "The stereo you weareo".