How Many Watts am I using?

[Swerd]

Yes, and that raises another issue. That 3/4 inch dome. The impedance curve shows the crossover to be in the 1.5 KHz region, which it would have to be given the bass/mids involved. The Tweeters are the very expensive Hiquphons. I think they use the the OW 4 now and not the OW 2, but the specs are almost identical. Recommended crossover for those tweeters is second order at 2.5 KHz.

As far as I know, the standard SongTower tweeter is the Hiquphon OW2, see Hiquphon's frequency response and impedance curves, where the tweeter's impedance peaks at 800-900 Hz, near it's resonance frequency point.

In the ST, the crossover is 4th order LR, at 2.5 kHz. This "Reverse Null" plot shows the simulated frequency response with the tweeter's polarity reversed.

And this frequency response plot shows on-axis and 60° off-axis plots. The on- and off-axis responses of the woofer begin to separate in the 1-2 kHz range, as the 15 cm woofers begin to beam sound as the frequency increases. At 2.5 kHz, the crossover frequency, the two FR curves coincide as the tweeter operates. The two curves diverge again as the frequency gets higher than 5 kHz.

 

[gzubeck]

highfigh,
Great minds think alike! In this case, I'm thinking just like you. My very first post on the AH was to introduce my room and my questions about how to improve it. shadyj jumped right in, in a pleasant way, and explained REW to me and what I should do with it. Including buying a new measurement microphone. I took his suggestions and we spent a couple of weeks trading messages and updating measurements etc etc.

I am a convert to REW and measuring your room and trying to be as data driven as possible for conversations with others. Listening can be highly subjective, but to talk with others its best to have as much objective information as you can muster and REW will indeed do that. We traded notes and I think I got my room/speakers sounding as good as they are going to without a hardware change. I ordered a pair of Salk Songtowers after the discussion as the best way to make a real improvement in my sound.

A cube has limitations as you mentioned. REW, shadyj and swerd helped me figure out where I was in relation to problems and how best to solve them. I am still awaiting my Salk Songtowers. I started this "how many watts am I burning " thread to help me understand power requirements. Not so much for my current speakers, but so if I need anything I can have it in place for my Songtowers.

I own the a300...you wont regret it! Yes it makes a difference because more clean power will not clip your tweeters and give you flabby base. If you have hungry speakers you will experience effortlessness driving higher more demanding speakers. I also own the a100 and it definitely did not have the power I needed.

 

[Swerd]

Bucknekked

We'll be glad to solve any other problems you have – with your money .

However, DO NOT ask about what new speaker cables you should get .

 

[PENG]

I love my 3805 and 4308 (gave that away), why someone would sell it to you is hard for me to imagine. Those AVRS are every bit as good as any integrated amps for the same price or slightly higher, but we all know it is practically impossible to fight Placebo effect.

 

[Verdinut]

Be careful Buck. Those Songtowers each have a pair of SEAS high value woofers, from the Prestige line. They are about $70 each. They don't pretend to have a high power motor system. For the two of them you have 120 watts to play with. Forget peak power. They are 4 ohm.

Contrary to the wisdom round here speakers are usually blown by too much power and not too little.

What you really need is a better amp in the 150 to 200 watt class. I don't have a very high opinion of receiver amps. Amps do not all sound the same. The problem is in the real world they are not driving resistive loads which they are measured driving. In the real world they have an infinite number of complex reactive loads to deal with.

I think most of us who have been in this a long time, have their favorite amps. Mine is the Quad 909. They seem very stable and rise to the occasion no matter what you throw at them. The 909 is replaced by the QSP now, but I think the 909 is the better bet. They come up on eBay and usually go for $700 to $900 and sometimes more. You won't ever loose money on one, their value stays up. Even the old Quad 405-2 still fetches $400 to $500 on eBay, and the very old Quad 303 frequently do for over $300. Any Quad gear that comes up gets lots of bids.

Quad gear has an enormous following. Quad will still service the old gear and there are lots of trustworthy on line places to get service. This is seldom required as Quad gear is very reliable. Peter Walker regarded a failure in any unit, even an old one as a personal afront.

What I would suggest to Buck if he has difficulty finding a Quad 909 is looking for a reasonably priced pro audio amp such as the QSC RMX850a ($399) which is rated at 280 watts/ch with a 4 ohm load and 0.1% THD from 20-20K and a 2 dB headroom. It's a Class A/B unit weighing 35 lbs and built like a tank.
Input sensitivity is 1.15 Vrms for full rated output at 8 ohms and Voltage Gain is 31.6 (30 dB).

Since it has adjustable gain controls at the front, they could be fixed as needed. Also, that amp has clipping limiter switches that don't prevent clipping but just limit it according to QSC.

The possible contra-indication to getting this amp might be the noise from the variable speed cooling fan, but I understand that one can obtain a more silent one direct from QSC.

What say you?

 

[PENG]

I read the British Miller Audio Research AVtech bench test data for the 909. The Denon AVR3805 and 3808 did better than the Quad 909 in most areas that count including output into 4 ohms and the preout level. The Quad failed the 1 ohm test, the Denon passed all tests, pages of them.

 

[lovinthehd]

I read the British Miller Audio Research AVtech bench test data for the 909. The Denon AVR3805 and 3808 did better than the Quad 909 in most areas that count including output into 4 ohms and the preout level. The Quad failed the 1 ohm test, the Denon passed all tests, pages of them.

I almost passed on the 3808 but when ParadigmDawg lowered the price to $125 (plus shipping) I couldn't resist. I'd been looking for something around $200 used locally but nothing this good had hit CL in a couple months of checking.

 

[PENG]

I almost passed on the 3808 but when ParadigmDawg lowered the price to $125 (plus shipping) I couldn't resist. I'd been looking for something around $200 used locally but nothing this good had hit CL in a couple months of checking.

You can follow the link below to see the test results, look under the HiFi News 2007 year book for the Quad 909 and Nov 2007 for the Denon AVR3808. You have to register but it is free.

To see the tests done in 2004, you don't need to register, you will find the 3805 there.

The Quad is flatter at 20k and above but both are virtually ruler flat. The Denon did better in power output, even passed the 1 ohm test that many failed including the NAD's.

http://www.milleraudioresearch.com/avtech/

 

[PENG]

To be clear, I don't doubt the Quad 909 is a better amp and I know TLSG don't think much of AVRs. I hope he's more open minded to see that some AVRs, typically the flag ship and the one or two models below that from Denon, Yamaha, NAD and a few others, do have very decent power supplies and amp sections that can do as good or better job than integrated amps in the same price range. In fact those 7.1/9.1 AVRs typically have better dynamic capability than some integrated amps when used for 2 channel stereo listening.

 

[yepimonfire]

Has anyone actually heard an amplifier running out of headroom? I know what digital clipping sounds like but I've never been able to tell if my receiver is clipping. At one point in time I was using an ultra cheap htib receiver and decides to try and watch a movie at reference level just to see if I would actually get distortion. I know my speakers weren't distorting because klipsch bookshelves show low levels of thd even at 105dB but as far as I could tell the only thing I noticed was that the sound sounded kind of harsh, though this could have been the fact that it was insanely loud.

I've also tried to drive my onkyo tx sr 707 into distortion by hooking an old rat shack bookshelf that was broken on the corner. It was rated for 100w rms, but the speaker blew before I hit clipping.

What other types of things can one get besides straight up clipping? Compression of dynamics?

Sent from my SM-G360T1 using Tapatalk

 

[Verdinut]

Has anyone actually heard an amplifier running out of headroom? I know what digital clipping sounds like but I've never been able to tell if my receiver is clipping. At one point in time I was using an ultra cheap htib receiver and decides to try and watch a movie at reference level just to see if I would actually get distortion. I know my speakers weren't distorting because klipsch bookshelves show low levels of thd even at 105dB but as far as I could tell the only thing I noticed was that the sound sounded kind of harsh, though this could have been the fact that it was insanely loud.

I've also tried to drive my onkyo tx sr 707 into distortion by hooking an old rat shack bookshelf that was broken on the corner. It was rated for 100w rms, but the speaker blew before I hit clipping.

What other types of things can one get besides straight up clipping? Compression of dynamics?

Sent from my SM-G360T1 using Tapatalk

A woofer catching fire!

 

[TLS Guy]

As far as I know, the standard SongTower tweeter is the Hiquphon OW2, see Hiquphon's frequency response and impedance curves, where the tweeter's impedance peaks at 800-900 Hz, near it's resonance frequency point.

In the ST, the crossover is 4th order LR, at 2.5 kHz. This "Reverse Null" plot shows the simulated frequency response with the tweeter's polarity reversed.

View attachment 20336

And this frequency response plot shows on-axis and 60° off-axis plots. The on- and off-axis responses of the woofer begin to separate in the 1-2 kHz range, as the 15 cm woofers begin to beam sound as the frequency increases. At 2.5 kHz, the crossover frequency, the two FR curves coincide as the tweeter operates. The two curves diverge again as the frequency gets higher than 5 kHz.

View attachment 20337

Odd that the impedance peak is 1000 Hz before crossover. However the crossover is second order electrically, as you can tell from the pictures. However both the woofer slope and the tweeter slopes are second order, so when you combine the two you get fourth order. So the tweeter power would be 18 db down by resonance, and so the speaker would handle 100 watts as far as the tweeter is concerned.

 

[TLS Guy]

I read the British Miller Audio Research AVtech bench test data for the 909. The Denon AVR3805 and 3808 did better than the Quad 909 in most areas that count including output into 4 ohms and the preout level. The Quad failed the 1 ohm test, the Denon passed all tests, pages of them.

I don't build speakerswith an impedance that goes anywhere near one ohm, and nor should anyone else. A speaker with an impedance dropping to one ohm has a crossover in resonance and is a dreadful speaker period, not meriting any consideration.

The Quad current dumping amps are very reliable and maintain specs over extremely extended periods of time. The design is very elegant with a very low part count. You get a class A amp that runs cool providing a very relaxed sound. For domestic purposes I don't know of a better all round performer.

This is my power house, and I'm sticking with it.

 

[Bucknekked]

What you really need is a better amp in the 150 to 200 watt class.
I think most of us who have been in this a long time, have their favorite amps. Mine is the Quad 909. They seem very stable and rise to the occasion no matter what you throw at them. The 909 is replaced by the QSP now, but I think the 909 is the better bet. They come up on eBay and usually go for $700 to $900 and sometimes more.

TLS Guy
I have taken a quick look around for Quad's for sale. Tough sleddin' right now in the U.S. market. I see a couple in the U.K., but priced like the existing owner loves them a lot. I don't doubt they have a great following based on a solid reputation and performance. Right now, I don't see anything up for sale in the Quad 909 space, but, I only looked for 10 or 15 minutes. Not an exhaustive search.

I have time to search around and evaluate choices. That's what's nice about this situation : I don't actually have to do anything, but, if I choose to do something I have a wide array of great choices. The hard choice is already made : get the Klipsch out of my room and get the Salks installed. Amps and power are just icing on the cake.

 

[yepimonfire]

A woofer catching fire!

Ha. No the voice coil just melted and it got stuck and flipped the protection on the amp. I did this with a 40hz tone so it would be obvious if there was clipping because the tweeter would start making noise.

Sent from my SM-G360T1 using Tapatalk

 

[highfigh]

Has anyone actually heard an amplifier running out of headroom? I know what digital clipping sounds like but I've never been able to tell if my receiver is clipping. At one point in time I was using an ultra cheap htib receiver and decides to try and watch a movie at reference level just to see if I would actually get distortion. I know my speakers weren't distorting because klipsch bookshelves show low levels of thd even at 105dB but as far as I could tell the only thing I noticed was that the sound sounded kind of harsh, though this could have been the fact that it was insanely loud.

I've also tried to drive my onkyo tx sr 707 into distortion by hooking an old rat shack bookshelf that was broken on the corner. It was rated for 100w rms, but the speaker blew before I hit clipping.

What other types of things can one get besides straight up clipping? Compression of dynamics?

Sent from my SM-G360T1 using Tapatalk

I have- in the '70s, most manufactures made receivers that were rated for not much power into an 8 Ohm load. The local McIntosh dealer had an amplifier clinic, where they connected people's amplifiers to load resistors and a distortion analyzer to check the actual vs claimed output, complete with a printout. My trusty Pioneer SX-525 put out a whopping 13W/channel at 1% and it wasn't much more at clipping. Talk to almost anyone who was a teenager in the '70s and you'll hear stories about people cranking their stereo wide open. These incidents also resulted in a huge number of blown speakers.

It sounds bad. REAL bad.

If you didn't hear distortion, it's because you don't know what it sounds like. There's no chance that any HTIB could be cranked to WOT and NOT distort. It's impossible. And ALL speakers distort. It doesn't sound like a distorted guitar, but it is distorted.

 

[PENG]

TLS Guy
I have taken a quick look around for Quad's for sale. Tough sleddin' right now in the U.S. market. I see a couple in the U.K., but priced like the existing owner loves them a lot. I don't doubt they have a great following based on a solid reputation and performance. Right now, I don't see anything up for sale in the Quad 909 space, but, I only looked for 10 or 15 minutes. Not an exhaustive search.

I have time to search around and evaluate choices. That's what's nice about this situation : I don't actually have to do anything, but, if I choose to do something I have a wide array of great choices. The hard choice is already made : get the Klipsch out of my room and get the Salks installed. Amps and power are just icing on the cake.

Grab this one, but you may want to ask TLS Guy nicely to inspect and test it out.

http://www.canuckaudiomart.com/details/649298725-quad-405-poweramplifier-serviced-and-upgraded-in-aug-2016/

Price is in C$ so approx USD 660 before negotiation.

 

[PENG]

I don't build speakerswith an impedance that goes anywhere near one ohm, and nor should anyone else. A speaker with an impedance dropping to one ohm has a crossover in resonance and is a dreadful speaker period, not meriting any consideration.

The Quad current dumping amps are very reliable and maintain specs over extremely extended periods of time. The design is very elegant with a very low part count. You get a class A amp that runs cool providing a very relaxed sound. For domestic purposes I don't know of a better all round performer.

This is my power house, and I'm sticking with it.

Good morning TLSG, I agree the 1 ohm test means nothing, and I have no idea why that British test lab bothered to make it their apparently standard test. I don't have doubt the Quad 909 amps are among the best ever made. I cited those bench test data only meant for you to see that not all AVR amps are weak, like not all non AVR amps are good, and I am talking about power output capability for 2 channel stereo purposes.

I know all amps don't sound the same, but I believe all amps with similar honest specs (verifiable in labs) in distortions, V/I capability, damping factor, freq response, I/O impedance etc., will sound audibly the same or similar enough such that one may notice a slight difference that is hard to say one sounds better than the other, when Placebo effects are eliminated and any slight preference would be a subjective matter.

 

[sterling shoote]

Listening has, so far, served to suggest having adequate power. Back in the late 80's I purchased a sub. This was originally powered by a bridged stereo amp operating at about 300 watts in mono. This was not enough power, as discerned by clipping, which sounded like a sledge hammer striking a steel pylon. Moving on to another stereo amp operating at about 600 watts in bridged mode the clipping vanished. What I learned from this was READ THE SPEAKER POWER REQUIREMENT SPECIFICATIONS before buying speakers or amplification.

 

[PENG]

I have- in the '70s, most manufactures made receivers that were rated for not much power into an 8 Ohm load. The local McIntosh dealer had an amplifier clinic, where they connected people's amplifiers to load resistors and a distortion analyzer to check the actual vs claimed output, complete with a printout. My trusty Pioneer SX-525 put out a whopping 13W/channel at 1% and it wasn't much more at clipping. Talk to almost anyone who was a teenager in the '70s and you'll hear stories about people cranking their stereo wide open. These incidents also resulted in a huge number of blown speakers.

It sounds bad. REAL bad.

If you didn't hear distortion, it's because you don't know what it sounds like. There's no chance that any HTIB could be cranked to WOT and NOT distort. It's impossible. And ALL speakers distort. It doesn't sound like a distorted guitar, but it is distorted.

Agree, it is obvious that a lot of people either don't notice or don't care about a few % distortions of any kind. People used to crank those 5WPC to fill their room and not bothered by the distortions that probably were >10%. Mind you, those Telefunken/Grundig radio/amplifiers were all tube stuff.

https://cdn.globalauctionplatform.com/b90aeb51-f66d-4b55-82d9-a4d800ad532a/61d6bab6-ed2c-4594-8582-bcca7cbfa533/540x360.jpg