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Question about Seas L26RO4Y in parallel

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Posted on July 23, 2024 at 03:11:10
pushpulltriode
Audiophile

Posts: 813
Joined: September 20, 2000
 If wired two of Seas L26RO4Y in parallel, the loaded impedance would be 2 ohm. What is the minimum impedance of two Seas L26RO4Y in parallel under 120Hz?

 

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RE: Question about Seas L26RO4Y in parallel, posted on July 23, 2024 at 08:55:27
tomservo
Manufacturer

Posts: 8615
Joined: July 4, 2002
 Look at the impedance curve and think, about one half that.
In a box, that curve is shifted upward somewhat, where Rmin is, will be a higher frequency as well

 

RE: Question about Seas L26RO4Y in parallel, posted on July 23, 2024 at 23:22:42
hahax@verizon.net
Audiophile

Posts: 4430
Location: New Jersey
Joined: March 22, 2006
 The lowest the impedance curve is 5 ohms below 120 Hz so two in parallel is half that or 2.5 ohms. But you also have to take into account the reactance, where the voltage and current are out of phase which can only make the load worse.

 

RE: Question about Seas L26RO4Y in parallel, posted on July 24, 2024 at 01:55:57
pushpulltriode
Audiophile

Posts: 813
Joined: September 20, 2000
 It won't reach 2 ohm as minimumm load then.

 

Depends on your method of "...- below 120Hz", posted on July 24, 2024 at 08:18:16
Edp
Audiophile

Posts: 4609
Joined: September 23, 1999
 If you do passive filter, you will get below 2 ohms

What amp are you planning to torture with this load? Car Audio, Pro or Sound Reinforcement Audio?

SEAS does make an 8 ohm L10ROY, but sealed only, or a giant Transmission Line

 

I usually am not in favor of active loudspeakers..., posted on July 24, 2024 at 09:29:17
John Marks
Manufacturer

Posts: 7985
Location: Peoples' Democratic Republic of R.I.
Joined: April 23, 2000



I usually am not in favor of active loudspeakers. The exceptions are:

(i) the active designs from ATC, because they still use analog amplification; and

(ii) subwoofers, because DSP-enabled digital plate amps get the job done with the least amount of fuss.

You haven't disclosed your implementation, but because you mention 2 woofers in parallel, my guess is that you are thinking about a mono subwoofer.

The Hypex 252 might be just the ticket.

john

 

RE: I usually am not in favor of active loudspeakers..., posted on July 24, 2024 at 20:49:22
hahax@verizon.net
Audiophile

Posts: 4430
Location: New Jersey
Joined: March 22, 2006
 And I am in favor of active speakers. Passive crossovers are evil. They make many amplifiers unhappy. I do understand your aversion to doing active digitally but digital is getting better and better.

By the way I like ATC speakers a lot and would probably buy ATC 50A active speakers if I was in the market and not retired. Plus just for historical interest ATC50A active speakers were the last speakers Gordon Holt spent his own money on telling me they were one of a very, very few speakers that made the live recordings he did(he did lots of recording) sound like what he heard at the actual event.

 

RE: Depends on your method of "...- below 120Hz", posted on July 25, 2024 at 01:51:34
pushpulltriode
Audiophile

Posts: 813
Joined: September 20, 2000
 I'm upgrading my reference, and the Linkwitz is under consideration for my small room.

 

The we agree that the OP should check out the Hypex DSP digital plate amp!, posted on July 25, 2024 at 07:21:18
John Marks
Manufacturer

Posts: 7985
Location: Peoples' Democratic Republic of R.I.
Joined: April 23, 2000



I built a stereo amp out of a Hypex OEM module.

A Golden Ears friend said that it sounded more "analog" than my Parasound Zamp 3.0. Which is an A/B analog amp.

john

 

Just so you know..., posted on July 25, 2024 at 10:16:56
E-Stat
Audiophile

Posts: 38789
Joined: May 12, 2000
Contributor
  Since: April 5, 2002
 Hypex Class D amps (nor most for that matter) are NOT "digital" amps.

Switchers, yes but they operate in the analog domain. Let Bruno Putzeys 'splain it to you...

 

RE: Just so you know..., posted on July 25, 2024 at 11:47:03
tomservo
Manufacturer

Posts: 8615
Joined: July 4, 2002
 I think the term (digital) come from the way the output is generated. These are a PWM or pulse width modulator where the output is not linear like A or AB, B but a switch closure between a high or low power supply voltage.

IF that switch is very fast but is only "on" 10% of the time, the power delivered is 10% of what would be possible if the load were connected directly to the power supply.

The up side is unlike a linear output where the device dissipation is the current times the voltage across it, the switch is either on or off, neither condition dissipates much energy.

The trick is, the switching frequency has to be much higher than the highest audio frequency in question, typically at several hundred KHz.
The higher the switch frequency, the easier it is to make the low pass filter that turns this into analogue and then, the easier it is to "close the loop" around the output.

 

You're mistaken, posted on July 25, 2024 at 12:23:45
E-Stat
Audiophile

Posts: 38789
Joined: May 12, 2000
Contributor
  Since: April 5, 2002
There is nothing handled in the digital domain with any of Bruno Putzeys class D designs - UCD, Hypex, Mola Mola or Purifi. Switch mode amps are inherently analog in their operation just like John Ulrick's Infinity SWAMP amp introduced in the 1970s. Hypex amps have analog inputs and analog outputs.

Just ask him.

A class-D power stage," Putzeys wrote in an email, "just like a class-A power stage, produces distortion that depends on the power supply and on the output current that the speaker draws." Engineers deal with that distortion via what Putzeys called "highly analog countermeasures." If a problem has an analog solution, then it must be an analog problem. Besides, you can't make a loudspeaker's cone move with code."

Remember this from the link found in the previous post?

Such, however, does exist with products like the NAD M2 "Direct Digital" amp which contains a DAC to do initial conversion for analog inputs to the digital domain.

 

RE: You're mistaken, posted on July 25, 2024 at 13:39:24
hahax@verizon.net
Audiophile

Posts: 4430
Location: New Jersey
Joined: March 22, 2006
 Agreed, all class D amps are analog. Class D is an analog format. It's unfortunate that it's called class D especially since the signal is encoded and decoded but it is an analog encoding. The combination of encoding and the name class D makes people who don't understand the format assume D is for digital since we live in a digital universe these days.

The reason it's called class D is simple. There were 3 formats defined previously. They were A, B, C(decidedly not an audiophile format). And the fourth format was D since D comes after C.

 

Exactly, posted on July 25, 2024 at 13:55:54
E-Stat
Audiophile

Posts: 38789
Joined: May 12, 2000
Contributor
  Since: April 5, 2002
 similarly folks often assume the wrong answer to the prefix found on Armalite products. It represents the company name.

 

Define "small room", posted on July 25, 2024 at 14:43:41
Edp
Audiophile

Posts: 4609
Joined: September 23, 1999
 Any dipole speaker, no matter its construction or method, they need room from back wall or benefit of dipole greatly diminished and turns into a foe to be slain.

LX5 series is not normally a small room speaker, but there are different definitions of small room

As to your questions on amps required for dual four ohm speakers, the Linkwitz site has detailed answers as to amp types depending on the different filtering methods and amp types

 

RE: You're mistaken, posted on July 25, 2024 at 15:04:18
tomservo
Manufacturer

Posts: 8615
Joined: July 4, 2002
 I never said anything was in the digital domain, i explained how the output signal is produced internally and HOW one could think it was digital.

The process is called a pulse width modulator and is based on an electronic "switch closure" and it's duty cycle. I designed several of these in the past for servomotor driven subwoofers and a 100 amp regulator that flew in the shuttle. See if the description makes sense including closing the loop with negative feedback

 

Ok, posted on July 25, 2024 at 15:07:47
E-Stat
Audiophile

Posts: 38789
Joined: May 12, 2000
Contributor
  Since: April 5, 2002
 sounds like but isn't.

 

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