Looking for thoughts on ATI amps

[Irvrobinson]

Well, with 4 x 9” Woofers each speaker, which is about 2 x 12” woofers, I can see why they would need 120W in Full Range mode. Each tower is like a subwoofer.

I think any tower with at least 2 x 10” woofers would need 100W+ power in full range, like a subwoofer would.

But most speakers don’t have dual 10” woofers, so most probably don’t even need more than 100W.

The Blade bass section is nothing like a competent subwoofer, having heard them with familiar material. There’s considerable cone area, but the system tuning, and I’m guessing the driver design, are not like a sub at all. I loved the Blades, but IMO they need subs for the 20-30Hz range. I also think Blades have a high low-distortion output capability, like the Salon2s, so you tend to listen louder than with more modest speakers, which gives people the impression of the speakers needing more power.

 

[AcuDefTechGuy]

@AcuDefTechGuy @PENG, top of the Morning fellow AH members! My head hurts this morning to many cold brews last night had umm 4 or 5. Anyways PENG, good luck trying to get Doc, @TLS Guy to try AC. One thing about Doc, man stands his ground when it comes to crappy speaker builds no matter who built them. So if you do try to Convince Doc and get out alive please let Inquiring minds know. I haven't seen anyone on AH get to Doc not even @gene , Doc has looked death in the eyes and Won! Best of luck PENG with that I will start a Collection plate for your funeral. just jacking around, mostly.

Well, Mike, we don’t need to convince anyone. I won’t even try.

It’s common sense that the big WOOFERS (dual 10” or dual 12” woofers) need the most Power. That’s why most big woofers may be rated for 500-1000W, but the midrange and tweeters are rated for 10-100W.

If @PENG could go back in time, he might have asked the store manager to set all speakers to small and used subwoofers for the bass, instead of letting those 8 x 9” Woofers handle the bass. Then he could take some pictures to show that the watt-meter would stay around 1W-10W the entire time.

@Danzilla31 texted me the other day and said that looking at his power/watt meter, his entire system with all speakers, 2400W-powered subwoofer, pre-pro, and amps showed a total of 400 watts. That’s the entire system.

So if the entire system is using a peak of 400W, I would say the 2400W-active subwoofer is probably responsible for at least 300W. And all of his 9 speakers are responsible for less than 100W.

In my 22x23x13 very open living room, the two RBH SV-1212N subwoofers are being powered by a single RBH SA-500DSP 500W amp. Like most people, the volume/gain for the subs is set to about 1/4. I would say each sub needs less than 200W, even when I sing Karaoke. Yeah bro, it’s all good.

Based on my experience with using passive subs with external amps and watt meters, this makes perfect sense.

Big Woofers require most of the power. The big woofers can be in subwoofers or speakers, it doesn’t matter. So if you are allowing 8 x 9” woofers in the tower speakers handle all the bass, it would need 130W. Otherwise, it would not.

 

[AcuDefTechGuy]

The Blade bass section is nothing like a competent subwoofer, having heard them with familiar material. There’s considerable cone area, but the system tuning, and I’m guessing the driver design, are not like a sub at all. I loved the Blades, but IMO they need subs for the 20-30Hz range. I also think Blades have a high low-distortion output capability, like the Salon2s, so you tend to listen louder than with more modest speakers, which gives people the impression of the speakers needing more power.

I agree. They probably won’t compare to dedicated high-output subs. But my only point is that those 8 x 9” woofers require most of the power.

Those KEF Blades woofers might not have been designed for larger excursions like high-output subs.

But at the same time, when you and probably 100% of people heard the Blades, those 8 x 9” woofers were NOT actively powered - they were only passively powered.

If those 8 x 9” woofers were actively powered (using external subwoofer amp with XO/EQ, even with speakers Internal XO 100% intact), you could control the output of those woofers with the sub amp volume/gain knob. This will increase the bass output for sure.

However, it will depend on the excursion limits of those 8 x 9” woofers.

 

[Gmoney]

I agree. They probably won’t compare to dedicated high-output subs. But my only point is that those 8 x 9” woofers require most of the power.

Those KEF Blades woofers might not have been designed for larger excursions like high-output subs.

But at the same time, when you and probably 100% of people heard the Blades, those 8 x 9” woofers were NOT actively powered - they were only passively powered.

If those 8 x 9” woofers were actively powered (using external subwoofer amp with XO/EQ, even with speakers Internal XO 100% intact), you could control the output of those woofers with the sub amp volume/gain knob. This will increase the bass output for sure.

However, it will depend on the excursion limits of those 8 x 9” woofers.

Umm Polk LSiM uses those 5X7 and 6X9 woofers in their old flagship speakers. Two of them so like what that comes to in terms of say a 15" woofer? more power needed right? It's nothing new with Manufacturers using speakers with that design of woofers Golden Ear has, Definitetechnology has. But they put amps inside each speaker something I didn't like cause when the amp craps out only 3 years warranty on amp maybe if your lucky most only give 2 years far as I know and can't get a replacement amp so the end user is out of luck. You call into CS and they go, oh but umm we can't get any replacement amps from China! But here's s 25% off our new flagship line. Yeah ok Not!!

 

[Irvrobinson]

I agree. They probably won’t compare to dedicated high-output subs. But my only point is that those 8 x 9” woofers require most of the power.

Those KEF Blades woofers might not have been designed for larger excursions like high-output subs.

But at the same time, when you and probably 100% of people heard the Blades, those 8 x 9” woofers were NOT actively powered - they were only passively powered.

If those 8 x 9” woofers were actively powered (using external subwoofer amp with XO/EQ, even with speakers Internal XO 100% intact), you could control the output of those woofers with the sub amp volume/gain knob. This will increase the bass output for sure.

However, it will depend on the excursion limits of those 8 x 9” woofers.

Of course the woofers take most of the power for nearly all music, especially with a 350Hz low-pass crossover to the woofers. What you’re discussing however is that you want to change the spectral balance of the Blade’s output to suit your preference. It’s just a fact that the F3 of the Blade is 40Hz. That is not subwoofer territory, volume control for the woofers or not. What you’re proposing will likely make them sound worse, not better.

 

[PENG]

If @PENG could go back in time, he might have asked the store manager to set all speakers to small and used subwoofers for the bass, instead of letting those 8 x 9” Woofers handle the bass. Then he could take some pictures to show that the watt-meter would stay around 1W-10W the entire time.

But if I remember right, in at least one of my rebuttal to TLSG's I did poste some measurements so he could see the difference. Also if I remember right, he did not disagree with my measurements so he might have agreed to me to a point. Again, all hinge on iirc.. I might try to do a search and see if I can found that post, because I could no longer find any of the measurements I took I am sure I still have them, but got buried in so many hard drives.

 

[M Code]

Regarding woofer sizes...
Keep in mind..
For example, a 10" subwoofer vs. 8" subwoofer, the 10" will have 3dB higher output..
Both sizes have the same motor structure(voice coil/magnet), same RMS input power and amplifier output rating, but the larger cone area of the 10" will move more air..

Just my $0.02...

 

[PENG]

Found some of the old posts on this silly debate on whether subs can lessen the burden on the power amp when used to watch movies:

Power draw by frequency: what am I missing?

It's been asserted, basically as a truism, that demands on the amp go up as the frequency goes down. This has been cited repeatedly as a reason to add a subwoofer to a given speaker setup (moving the most demanding loads to a dedicated amp). But I can't seem to figure out where I can find...

forums.audioholics.com

It might have started with TLSG (post#17) saying "So a sub does not actually off load much power from a receiver, very little in fact. What it does do is offload the the other speaker drivers. These days they are narrow speakers with small diameter drivers that do not have the excursion to produce bass at a realistic spl. So subs offload speaker drivers and power amplifiers hardly at all. It is on this last point there is huge ignorance and miss understanding. So the oft repeater phrase that a sub relieves a receiver from doing the heavy lifting is absolute nonsense."

For clarity, I don't disagree on everything he, and Jerry said in that thread. I just had trouble with blanket statements in general. So it was just a "soft" disagreement.

Power draw by frequency: what am I missing?

This is probably correct for symphony orchestras and baroque chamber music, but it's not true for modern pop music or some fusion jazz. (In my measurements it's also less true for Beethoven than Mozart, for example, but I digress.) I doubt you listen to Kanye West or Cardi B, but the bass...

forums.audioholics.com

Power draw by frequency: what am I missing?

I agree. But Verdinut has asserted that we need to take dynamic range into account when determining peak amp performance. So that question would be at him or someone who supports his assertion. I don't think he anticipated that you would set a spl level limit. He may be thinking that someone...

forums.audioholics.com

 

[lovinthehd]

If it is a conventional wattmeter, and Mc being old fashion afaic, no. It should be based on voltage and current, not impedance. Please don't get me started again on the misuse of technical terms again. I wish manufacturers start respecting the intelligent of their customers and use the right terms such as "average power", current (in amps/amperes/A), voltage, VA, instead of the popular error "rms power" that has no practical meaning.
I just think the public can understand it, if you explain to them, a moving coil loudspeaker will make sound when the diaphragm moves, and it moves when there the signal current flows, and current flows when the signal voltage is applied, and signal voltage, current are phasors (think vector on the mechanical side) so it has magnitude (unit in A) and phase angle relative to the voltage phasor (unit in degrees). So it isn't that complicated for most to follow, without Googling and might end to reading hearsay, spreading misconceptions like Covid.

For those who wants to understand a little more about the relationship between voltage, current (V, A, Degrees), spl (dB0, then they can Google and hopefully found the basic formula such as Power (VA) = Voltage (V) X I (A), Power (Watt) = Voltage (V) X I (A) X Cosine (Phase angle), and to get 2X SPL, the signal voltage to the speaker needs to go up by a factor of square root 2 (√2).

Yes it is easier to just use the single term Watt, or the incorrect term rms Watt that speaker "needs", but if the right term(s) are used, people would naturally have a better understanding of how to read amplifier specs and better chance to pick one that meets the requirements of their speakers.

Sorry, my frustration is not directed at you at all, but you just asked such an interesting question that triggered it...

I have Carver amps with vu meters that have readings based on the impedance, thus my question....don't know what is normal myself. On mine they're based on 8 ohm, and the manual indicates if 16 ohm the meters would be indicating half the power, on 4 ohm you'd need to double it....

 

[AcuDefTechGuy]

Of course the woofers take most of the power for nearly all music, especially with a 350Hz low-pass crossover to the woofers. What you’re discussing however is that you want to change the spectral balance of the Blade’s output to suit your preference. It’s just a fact that the F3 of the Blade is 40Hz. That is not subwoofer territory, volume control for the woofers or not. What you’re proposing will likely make them sound worse, not better.

Likely make them worse?

What is that? Your guessing without any experience with actively powering towers with subwoofer amps?

Even the Blade-2 can go down to 20Hz in-room. And the Blade2 has 4x6.5” woofers vs 4x9” woofers of the Blade1.

KEF Blade Two loudspeaker Measurements

Sidebar 3: Measurements

www.stereophile.com

Whether that is “subwoofer territory” or not depends on the subwoofer and room.

But actively powering the Blade1 in-room with an external sub amp will produce more output.

And what you’re proposing about how the sound is likely worse is your pure guess alone.

I’ve seen this done on the RBH SX-8300, which has 3x8” woofers, not 4x9” woofers. And it sounded awesome, not worse.

That’s my experience. Do you have any experience with actively powering the woofers of towers, other than just guessing?

 

[PENG]

I have Carver amps with vu meters that have readings based on the impedance, thus my question....don't know what is normal myself. On mine they're based on 8 ohm, and the manual indicates if 16 ohm the meters would be indicating half the power, on 4 ohm you'd need to double it....

Sure, and if so they would tell you in the manual or something as Carver did. Those are basically voltmeters, so will be impedance dependent. Again, either way, it is not even "watts" unless the voltage is applied to a 16, 8, 4 ohm resistor. Oops, I did it again..

 

[Irvrobinson]

Likely make them worse?

What is that? Your guessing without any experience with actively powering towers with subwoofer amps?

Even the Blade-2 can go down to 20Hz in-room. And the Blade2 has 4x6.5” woofers vs 4x9” woofers of the Blade1.

KEF Blade Two loudspeaker Measurements

Sidebar 3: Measurements

www.stereophile.com

Whether that is “subwoofer territory” or not depends on the subwoofer and room.

But actively powering the Blade1 in-room with an external sub amp will produce more output.

And what you’re proposing about how the sound is likely worse is your pure guess alone.

I’ve seen this done on the RBH SX-8300, which has 3x8” woofers, not 4x9” woofers. And it sounded awesome, not worse.

That’s my experience. Do you have any experience with actively powering the woofers of towers, other than just guessing?

How do you know the Blade2 goes down to 20Hz in-room? Have you played a 20Hz test tone through a pair?

Actually, I do have experience with separately amplifying and adjusting the level of the bass sections of speakers with bi-wiring/amping capability. I’ve even tried it on the Salon2s. Being a piano fan, I find the effect of this tweak to be too crude. It does nothing about room dips and peaks, and especially peaks can sound weird when amplified.

Passive subs with separate amps and crossovers was my original strategy with the Salon2s, and after considerable investigation I concluded it was a dumb idea, unless I used multi-band parametric EQ, and still didn’t solve the L/R versus sub placement paradox.

If you think driving the bass sections to higher volume is great, have at it. We just don’t agree, and yes I do have experience.

And by the way, a Blade can’t play a 20Hz test tone either in my experience.

 

[PENG]

And by the way, a Blade can’t play a 20Hz test tone either in my experience.

The Blade 2 in room should do okay down to 25 Hz if you can get some good room gain like JA's. The bigger original Blade should do a little better, I would think.. Without any room gain, it would probably drop more than 20 dB at 20 Hz but ADTG should still be able to hear the harmonics.

KEF Blade Two loudspeaker Measurements

Sidebar 3: Measurements

www.stereophile.com

Fig.8 KEF Blade Two, 1/6-octave response in JA's room at listening position (left speaker blue, right red).

 

[Irvrobinson]

The Blade 2 in room should do okay down to 25 Hz if you can get some good room gain like JA's. The bigger original Blade should do a little better, I would think.. Without any room gain, it would probably drop more than 20 dB at 20 Hz but ADTG should still be able to hear the harmonics.

KEF Blade Two loudspeaker Measurements

Sidebar 3: Measurements

www.stereophile.com

View attachment 40019

Fig.8 KEF Blade Two, 1/6-octave response in JA's room at listening position (left speaker blue, right red).

In the demo systems I’ve heard of the Blade and Blade2 they both had little or no discernible output with a 25Hz test tone or a 20Hz test tone. A 32Hz test tone was strong with both. It is possible that the lack of deep bass I heard was simply a room artifact both times, but I doubt it. Even in JA’s curve the bass response drops like a rock at about 30Hz, and 2nd order harmonic distortion plays a role in measurements like these and, unlike ShadyJ, JA doesn’t publish speaker distortion measurements. My conclusion was that the KEFs need at least dual subs and at least a 60Hz crossover frequency.

 

[RichB]

My guess is that the engineers don't write the spec sheets or any of the advertising copy. ATI is not the only transgressor. A while back the Revel web site reversed the labelling on the tweeter and upper bass drivers for the Salon2 speakers. I didn't take that as an indicator of their engineers' skills.

To be honest, ATI has come down a notch or two in my mind. First they put that horrendous Kessler signature on their 4000 and 6000 front plates, and then they stuck a linear power supply in their Class D amps, making them nearly as heavy as their old Class AB offerings. I'll almost certainly keep my ATI AT3005 until it breaks outside of the warranty coverage, but after that either the Benchmark ABH2 or the newest Class D monoblocks with switching power supplies are looking attractive.

I have moved to the AHB2, bi-amping the Salon2 fronts and Voice2. The rears use a single AHB2.
They idle at about 15 watts, run cool, weigh 12 pounds each.

For the vacation system. I needed a reasonably cool running 5 channel amp so selected the ATI AT522NC.
I am considering setting up a SBT between the two amps driven by 2 Oppo UPD-205s to level match.
Roon zones can send the same source to both Oppo's and a speaker switch is used to select the amps.

- Rich

 

[ParleyW]

ATI amps have excellent reputations – they are said to be first rate. They are one of the few amplifier manufacturers in the US.

Understand that ATI does manufacture amps for other companies under contract. For example, ATI builds amps for Monolith and Outlaw, built to their specifications, not ATI's. I once read that ATI can fabricate it's own steel chassis and wind their own transformers in their factory. So they can include those expensive parts in their contract builds instead of requiring that they be outsourced.

ATI now owns the B&K and Theta amp designs and company names. Those companies had gone out of business. It that true for Levinson as well?

They made my Crestron 7x200 amp I believe, and JBL Synthesis and Lexicon I believe. Really powerful.