SP TECH AND AMPLIFICATION

Tbadder1 · « **on:** 7 Nov 2005, 08:55 pm »

Okay, I'm champing at the bit. My Continuums are coming very soon, and after reading the reviews, following the threads, drooling over them for about two years now I'm rarin' to go. So I'll start by potentially putting my foot in my mouth. I believe in my heart of hearts, despite what I've read that I don't need no stinking two hundred watts per to drive these speakers with the quality they deserve. I'm betting myself that my 50 watts per are going work and make people drop their jaws at the same time.

I'm sure many of you are familiar with Clayton Audio. Well, these are the best amps I've ever heard, and my little S40 is stable down to 1 ohm, and I'm not talking just barely, I'm talking rock solid stable. I'm predicting that Clayton will beat these babies into submission--in a totally hot and seductive way.

With its pure class A and zero negative feedback, I'm going to rock the friggin house. These Continuums are gonna give each and every listener a pole dance--the blood will be flowing to all the right spots my friends!

Now I might be completely stupid, and I'll admit to the truth one way or the other, so hang in there and I'll write a review after listening for a couple of weeks. I've never believed in the quantity of watts; I've staked my audiophile existence on the quality of the watts. We shall see.

And if I win? I'll take myself out to my fav restaurant, and if I lose? Nothing but bread and water for weeks. I'll have to starve myself if this doesn't work, because if it don't, it'll cost my a Pass 250.5 I got me eye on.

zybar · « **Reply #1 on:** 7 Nov 2005, 09:00 pm »

Quote from: Tbadder1

Okay, I'm champing at the bit. My Continuums are coming very soon, and after reading the reviews, following the threads, drooling over them for about two years now I'm rarin' to go. So I'll start by potentially putting my foot in my mouth. I believe in my heart of hearts, despite what I've read that I don't need no stinking two hundred watts per to drive these speakers with the quality they deserve. I'm betting myself that my 50 watts per are going work and make people drop their jaws at the same time.
...

Before you go Pass x250.5, I would try the MCCormack DNA-500 or Belles Reference 350A. Whule I haven't heard the Pass.5 models, I did spend significant time with the x250 and x350 and thought the DNA-500 and 350A were better all around amps.

Those Clayton amps are very nice as well.

Good luck.

George

JAMn Joe · « **Reply #2 on:** 7 Nov 2005, 10:53 pm »

TBadder1,

You might want to bring your amp down to my place and do some testing. I've found the NuForce Ref9's to be a superb match with the Continuum AD's. I have a very good pair of 60 watt tube amps that yielded some good results with the Continuums but having more power clearly brings out the best in these speakers.

I'm located just South of the border about 8 miles west of Great America. Feel free to call me if you want to do a little playing and comparing before your speakers arrive.

Congratulations on a very good purchase!

Aether Audio · « **Reply #3 on:** 7 Nov 2005, 11:37 pm »

OK Guys,

You dragged me in on this one. Tbadder1, I am not about to tell you that 50 watts won't trip your trigger - especially hearing about your amps low-Z performance. But...

Juice is Juice!

It's a voltage thing. Amplifiers are rated into some standard impedance (AC resistance). Power in watts = Voltage squared/ impedance. As the supply voltage of the amp's output stage goes down, the rated power goes down - period. Amplifiers are "constant-voltage" devices. You inject a small voltage on the input, they put out a larger voltage at the speaker terminals. If the output voltage remains constant (because the input voltage remains constant) then the current drawn is determined by the impedance. The lower the impedance, the more current is drawn from the amplifier. The whole time the voltage will remain the same - regardless of speaker impedance/output current. Well, there is a limit. If the amp can't source enough current because the speaker impedance is too low - then the output voltage will drop even though the input voltage hasn't.

That leads us to the impedance rating of the amplifier. A theoretically perfect voltage-source/amplifier would continue to put out the same voltage, even into a dead short circuit - that's about as low of an impedance as you can get. If it will do that then you have an arc welder/amplifier combination. In my days at Crown, they could almost do that - without damage!

Anyway, if the amp is "good enough" to supply the current determined by the impedance of the speaker - well, all is well. But it won't make it play one dB louder! It just won't sound like crap as an amp that can't drive that low of an impedance would. If you want it louder, you need more voltage. Transients in digital recordings can be as much as 10dB louder than the signals that produce what we call the apparent "volume." That means if you don't want to EVER clip them, you need 10dB more VOLTAGE. 10dB more voltage = 3.16 times the voltage the amp is putting out at the average volume level. If the impedance is held constant (which would be the case unless you switch to a different speaker), then the increase in power necessary to avoid clipping the signal would = 10 times the POWER used at average listening level.

This means that if your average volume requires 25 watts, your peak power will need to be 250 watts to prevent clipping a 10dB transient.

Question: How loud do you like to listen, what is the sensitivity of your speakers and how much clipping can you tolerate? Conversly, how much do you like to impress your audiophile buddies or incur the wrath of your neighbors? Remember: Anarchism requires serious amplification!

Don't worry about the impedance. If the amp sounds good at moderate to low volumes, you most likely don't have an impedance issue (not a severe one anyway) and the amplifier's ability to drive your speaker is not a concern. And it's current-sourcing/impedance driving ability won't tell you much about how loud it will play. Rock-solid, low impedance driving ability is always a good thing, but it's not the right "yardstick" to measure it's ability to play loud and/or handle large transients.

End of thesis.

-Bob

PS. Millennial Reference Series products will handle/reproduce faithfully, transients that will literally destroy most loudspeakers...and hearing - but they need the VOLTAGE to do it!

bhobba · « **Reply #4 on:** 8 Nov 2005, 01:29 am »

Hi All

I must admit to having a bit of a chuckle when reading about amplifier power.

The source most people use these days is CD and I have read they are recorded with about 18db headroom on the average - to be safe let us assume 20db. So to produce transients without clipping one needs an amplifier with not 10 times the power but able to produce for a short time about 100 times the power at levels we would normally listen at.

Continually listening to volumes greater than 85db for extended periods is considered dangerous - and many places have laws that you must wear protective devices if you are exposed to it for any length of time (if I remember correctly it corresponds to the level of a power mower - would you like one of those in your listening room?). I have also found that if it gets to that level neighbors tend to complain. Thus I would consider this the maximum level I would go. Indeed using an SPL meter I find I never exceed 80db at about 1 meter from my speakers. That being the case the math would seem fairly simple. The continuums are rated at 88 db and are 4 ohms and since we have two of them for stereo this equates to 91db when fed 1 watt. So to get 85 db you need 1/4 watt. Thus 25 watts into 4 ohms (or equivalently 12.5 watts into 8 ohms) would seem sufficient. I know some people like to turn up the wick to impress friends etc but really is that what Hi Fi is about? I suggest not - I suggest listening at sane levels is more reasonable. And if you limit yourself to 80db or less then amplifiers with even less power would be OK eg the 8w clarlize which is supposed to be a superb amp and can be run from batteries - and only $90.00.
http://diyparadise.com/charlize.html
Trick it out with the highest quality parts such as black gates etc and it price is still small.

The amps mentioned such as the Clayton Audio class A cost many thousands of dollars. It is an example of something I read early on on my Hi Fi education. Excellent quality low power amps are a doddle to build at a reasonable price - raise the power and the price shoots up dramatically. The conclusion - listen at sane levels and you can save yourself a fortune.

Others such as Dave Ellis of Ellis audio seem similarly inclined as well:
http://www.ellisaudio.com/wattsratings.htm

Thanks
Bill

WEEZ · « **Reply #5 on:** 8 Nov 2005, 02:21 am »

I must admit that there is a sense of 'ease' when listening to a high power amplifier if one pushes the volume up. But..

..everytime I've owned a high power amplifier, I've sold it 'cause I simply don't listen to music at high volumes.

To me, hifi is more about how soft it will play- not how loud.

WEEZ

Bill Baker · « **Reply #6 on:** 8 Nov 2005, 02:25 am »

Interesting thread we have going here. I am also "champing at the bit" as I cannot decide between the Continuum 2.5 or the Revelation to start off with in our NY store. (Joe is bringing the Revelations in at Jam'n Audio). Either way, I am not one to have a lot of "higher" power solid state amps around, in fact other than a few 100 watt Hybrids, I have nothing but tubes.

With either of these speakers, they will often be driven by 70 watts of tube power from my Reference Jolida 801 and will be the speaker pf choice when burning in customers 200 watt Extreme Hurricanes. (that should do the trick).

The Continuums have proven to do quite well with the Reference 801 at 70 watts and whatever I decide to bring in first should do well with these amps also. Worst case, I will find the time to build my own pair of EXtreme Hurricanes.

Tbadder1.............. give it a shot. If you are happy with the combination, forget everything else and enjoy the music. Just be sure to keep an open mind when given the oppurtunity to audition other amps comes about.

Enjoy the speakers and more importantly, the Music!!

bhobba · « **Reply #7 on:** 8 Nov 2005, 03:35 am »

Hi All

I think by all means Thadder should listen to the amplifiers mentioned. But again (with the exception of some of the Jolida's) look at their price - thousands of dollars. I seriously question they are audibly superior to Nuforce amps which cost - if memory serves me correctly - $800.00 each. IMHO I believe the Nuorce 100w continuous - 260W peak is way overkill. I believe the 8 w Charlize would work fine at sane listening levels - remember to sound twice as loud it needs 10 times the power. Someone like the boulder cable company could build you an amp using this for $400.00 with very good sonics
http://www.audiocircle.com/index.php?topic=15411&sid=8c9bf6f5e3b76d6cac69cfe2926452a3
Now I have not heard these particular amps but I have heard the Panasonic digital amps and I think they are great. Indeed have a listen to your new speakers connected to a Panasonic XR55 - you may be surprised at what you hear.

By simply listening at half the volume of a 100w amp you can save big bucks. Caution - as Dave Ellis pointed out stay clear of SET designs - they really only have outputs of 1W. But aside from that I would be looking at less watts of higher quality power. Of course if you really feel the urge to turn up the wick - get lots of power. Just realize you are paying big for the privilege - and possibly damaging your hearing as well.

Thanks
Bill

lonewolfny42 · « **Reply #8 on:** 8 Nov 2005, 03:53 am »

Quote from: bhobba

Hi All

I must admit to having a bit of a chuckle when reading about amplifier power.

You may be having a chuckle...but you have not owned a pair of SP Tech speakers...

These speakers need

JUICE to sound their best.[/list:u]

audiojerry · « **Reply #9 on:** 8 Nov 2005, 04:48 am »

Tbadder,
I should have a Belles Reference 350A coming to Brookfield for evaluation. Let me know if you'd like to try it with the Continuum. I think it may help you decide if you need more power or not. Personally, I'd love to hear the Continuum with the 350A.

PS: I owned the Clayton S40. It was a very powerful 40 watter, and a great amp for the money. They are hard to come by these days.
Oh, btw, one doesn't have to spend thousands for an S40. If you can find one, you could pick one up for around $1200.

bhobba · « **Reply #10 on:** 8 Nov 2005, 05:01 am »

Quote from: lonewolfny42

Quote from: bhobba
Hi All

I must admit to having a bit of a chuckle when reading about amplifier power.
You may be having a chuckle...but you have not owned a pair of SP Tech speakers...
The comments made about haveing a good powerful amp...are true.[/list:u]
These speakers need
JUICE to sound their best.[/list:u]
If you get a chance, try to audition a pair. [/list:u]

Fair enough. I just wonder though whether it is because they need that amount of power or their low distortion coaxes you into winding up the wick - eg
http://www.linkwitzlab.com/Pluto/specs.htm
'With small speakers that produce a very clean sound there can be a tendency to drive them to their maximum capability. We judge a speaker's loudness primarily by how distorted it sounds, and not by how loud we have to talk in order to be understood by the person next to us.'
And since SP speakers can be driven very loud (much louder than any other speaker I am aware of) without distorting then that is what we tend to do - even subconsciously.

I did the same when I first got into Hi Fi with Gale loudspeakers which were known for that - they sucked power man and were known as difficult to drive but had a beautiful low coloration sound. I would delight in showing this off to friends who marveled at how it sounded when we cranked up the volume. Then one day a friend bought over this flea powered battery amp he built. Using an SPL meter to confirm I was reaching 75db (80 db is about the level of someone shouting) I found I was hearing more of the music listening at a comfortable level than to the 50 watter I had at the time. After that I was a convert to WEEZ's view. I still think a battery powered 8w amp is worth a shot with SP speakers, even with their timepieces that have 85db sensitivity. Allowing 20db headroom you can still reach the high 70db's. And it is often recommended that volume should be about what you would need to speak loudly to be heard over.

Thanks
Bill

lonewolfny42 · « **Reply #11 on:** 8 Nov 2005, 05:15 am »

Quote

Fair enough. I just wonder though whether it is because they need that amount of power or their low distortion coaxes you into winding up the wick

bhobba · « **Reply #12 on:** 8 Nov 2005, 05:31 am »

Quote from: lonewolfny42

But they really do soak it up....and play distortion free... [/list]

I think that is the key and why you prefer louder volumes. For your ears sake you might like to check SPL at your listening position does not exceed 85db average over prolonged periods. Regardless of how undistorted the sound is it will still damage your ears.

Thanks
Bill

lonewolfny42 · « **Reply #13 on:** 8 Nov 2005, 05:37 am »

Quote from: bhobba

Quote from: lonewolfny42
But they really do soak it up....and play distortion free... [/list]

I think that is the key and why you prefer louder volumes. For your ears sake you might like to check SPL at your listening position does not exceed 85db average over prolonged periods. Regardless of how undistorted the sound is it will still damage your ears.

Thanks
Bill

I do check levels...80 to 90 db is my range.

Rave link...

http://www.audiocircle.com/index.php?topic=19191[/list:u]

Aether Audio · « **Reply #14 on:** 8 Nov 2005, 06:22 pm »

Gentlemen,

To get the numbers exact, we offer the following:

The Continuum A.D., Continuum 2.5, and Revelation all offer a sensitivity of 88dB each @1watt/1meter. A stereo pair being driven and reproducing a MONO signal will produce an additional 3dB of SPL, thereby achieving a 91 dB overall sound pressure level at 1 meter.

If we select our listening position to be 3 meters, that same 1-watt will produce 81.458 dB from the pair. In order to raise the level to a nominal 85dB, we require and additional 3.542 dB of amplifier power. That equates to 2.26 watts of AVERAGE amplifier output. If we limit our available headroom to that of 10dB, a ten-fold increase in power is required. Our new power requirement indicates the need for 22.6-watts of amplification.

If we wish to avoid clipping any potential transient that represents a 20dB increase above the average 2.26-watt output, we obviously need 20db more power. 20dB is a 100-fold increase, meaning we now need a 226-watt amplifier.

If we were to raise our average SPL to 90dB at the same listening position, our power requirement now becomes an additional 8.542 dB, or 7.148 watts. Headroom for 10 and 20 dB transients now translates to 71.48 and 714.8 watts, respectively.

As we can see from the above examples, power requirements increase dramatically when transient levels are accounted for. As I see it, our options are to either always listen at moderate levels, sit real close to the speakers, use a peak limiter as is common in sound-reinforcement applications, listen only to analog source material, accept amplifier clipping or…use a BIG-ASS AMP!

Pick your poison – and have fun!

-Bob

Tbadder1 · « **Reply #15 on:** 8 Nov 2005, 06:34 pm »

Excellent! I do love starting up a discussion. Know that I will be objective as I can possibly be. I do have the advantage of having a small room right now...

and the advice about playing levels (anything over 85db for extended periods will destroy your ears) is serious enough to pay strict attention to. So if it is true that the Continuums need over 85db to really shine, then we've stumbled onto the Ferrari question. If you can only legally go 65, then why buy a 200mph car? Furthermore, why buy a car that's no fun to drive until it hits well over a 100? If the Continuums are no fun at 84db, what's the point? And if the fun is logrithmic until it hits 115db (just throwing out an outrageous number here) and points inbetween, what's the purpose? Are we building something just because we can? Geez, now I'm about dying to hear these things.

AudioJerry: I've got a new S40 which Clayton now claims is a solid 50 watts per. I had mine measured at about a clear 72 per channel before distortion started to take a toll. Clayton makes great amps, not good ones, great ones. I'd give the proverbial left testical to own some of their badass 300 or 500 watters. I'm pretty much convinced those could drive a fairly large mobile home much less a pair of low sensitive, inefficient speakers.

As far as your offer goes, I'd love to make the comparison someday with the Belles locomotive.

And of course I could be completely wrong about the Clayton/Continuum combo, which would be typical according to my ex-wife.

Take care all
Dan

P.S. I just gotta state publically what an upright guy Bob Smith is. He treated me like a million bucks throughout the entire deal, and it's pretty obvious he puts a ton of attention and time and hardwork into his products and customer relationship. If my ship every comes in I'll have to consider the Revelations based on my buying experience alone.

Bill Baker · « **Reply #16 on:** 8 Nov 2005, 06:50 pm »

Hey Bob,
Very nice facts by the way. Could you do us all a favor and jot down some info in regard to "over powering" a speaker. In other words, when we have to worry about voice-coil burnout and how to prevent it.

You are much better at putting these facts into words we can all understand. Give it to us!

woodsyi · « **Reply #17 on:** 8 Nov 2005, 07:34 pm »

Bob,

How sensitive are your woofers in tandem and the tweeter. Can you disconnect the passive (or do away with it altogether with lower price) and go active biamping? If yes, how much power do you need in each amp for 90db listening level?

Dan Banquer · « **Reply #18 on:** 8 Nov 2005, 07:41 pm »

I've been delving into this recently for an article coming up in Audioholics. I have been talking to some of the folks who do mega buck home installations and they are telling me the following.
Most folks do not go above 110db/spl peak from their speakers. That measurement is at the speaker itself. Above that things get a bit well, er........uncomfortable. According to what I have been told this seems to somewhat independent of room size. To reach 109 db/spl peak from an 88 db/spl speaker you will need 64 watts rms or 128 watts peak. I don't have the formulas on hand to calculate what it is exactly for 110 db/spl at the speaker but it should be close to 150 peak watts.
Now for those of you wish live sound reinforcement levels, just quadruple that number for starters, and enjoy it while you can because your neighbors aren't going to be happy campers, and you will be talking to the police when they knock on your door.

Hope this helps;
d.b.
P.S. I hope I got my math right.

Aether Audio · « **Reply #19 on:** 8 Nov 2005, 08:16 pm »

Tbadder1,

Quote

So if it is true that the Continuums need over 85db to really shine...

Not so!!! They are designed to be extremely linear from a dynamic standpoint. This doesn't just mean at the high volume/transient extreme either. We're talking both ways - up and down the dynamic ladder. Micro-dynamics "make the music" just as much as the transients do. Without sufficient dynamic linearity, the subtle details get lost, the ambient decay drops off suddenly and the speakers sound like canned AM radio - sterile and lifeless. We don't do that at SP Tech. It doesn't sound good. We like speakers to sound good.

There are three reasons why one may tend to listen louder, other than the fact he/she likes it loud. The first reason is, it seems all music has an SPL that it prefers to be played at. AC/DC, Led Zeppelin, Pink Floyd, etc. - no need for further explanation here. Mozart just ain’t the same at 105db either.

The second reason is a little more complex. The human ear has sensitivity issues with regards to frequency. Did you know a 20Hz signal HAS to be at least 85dB to even hear it? I’m sure there’s an exception somewhere but that’s considered average for most listeners. You want to hear the deep bass? You HAVE to turn it up.

The third reason is even more complex. In a room, there is a point where the level of reflected energy is the same volume as the direct energy coming from the speaker. This is called the “critical distance.” That distance is totally a function of the room’s absorption characteristics. Because sound absorbing materials are typically non-linear with regards to how much sound they soak up, it has been discovered that the critical distance can be “pushed” further back into the room. How do you “push” it? With VOLUME! As you increase the SPL, the ratio of direct energy to reflected energy increases at a given listening location.

Every good sound engineer knows that if he’s mixing a gig in a bad venue (highly reverberant room), he can somewhat compensate by turning up the volume of the house system. Consonant intelligibility increases and the audience can hear the “mix” better. There is a theoretical limit to this but it does work pretty well in most cases. So that’s why the last rock concert was so loud…well, that’s may be part of the reason anyway. That… and the soundman is deaf by now.

Anyway, audiophiles may be doing the same thing with their systems in their homes. Are you trying to hear all the detail in a recording? I know I do. Well, you may find yourself wanting to turn up the volume then. Are you a head-bashing metal junkie? You don’t have to be to still want it a little loud. All you’re doing is pushing the critical distance back further into the room when you do. Isn’t that part of the reason you obsess over this hobby to begin with – because you want to hear every detail such that it sounds like live music? Forgive yourself…it’s not your fault…you can’t help it. Repeat ad infinitum.

If you can’t/won’t play at louder volumes, then you might want to consider acoustic treatment of your room. Making it deader will bring the critical distance out further into the room. You won’t need as much volume then to have the same effect. But then you'll have a dead room (if you aren't careful). That opens another whole can of worms.

So here we go, even more complexities to ponder. Do you NEED to turn it up loud? The truth is, you just might. It’s OK, I understand…and so do our speakers. In fact, they like it. Just ask them, they’ll tell you so.

-Bob