How to fix my detailed, accurate but BRIGHT system

I'm not disagreeing with your discussion of low output impedance. However, in rereading Harley's discussion of power output into varying impedance loads, and the resulting loudspeakers' varying dbW (decibel watts) measurements, he makes no mention of low output impedance negating the effect. Perhaps this is an issue of voltage paradigm versus current paradigm?

I don't have Harley's book, and so I don't know exactly what he is saying, but yes the question can be considered in the context of the two paradigms of amplifier and speaker design. Those being the voltage paradigm, and the power paradigm, which is more accurate terminology than "current" paradigm, as explained in Ralph's (Atmasphere's) excellent paper on the two paradigms.

Consider the output stage of an amplifier to be a theoretically ideal voltage source (zero output impedance), the voltage being proportional to the amplifier's input voltage, in series with a resistor (equal to the amplifier's output impedance).

In a voltage paradigm amplifier, by definition, the value of that resistor approaches zero (i.e., it will be a small fraction of an ohm). The result is that the speaker will see a voltage proportional to the amplifier's input voltage, regardless of what the speaker's impedance may be at the frequency that is involved (as long as the amplifier is capable of supplying the required current, the required current being higher as the speaker's impedance decreases -- recall Ohm's Law). Nearly all amplifiers with solid state output stages work this way, and the majority of conventional box speakers are designed based on the assumption that they will be driven this way. Many tube amplifiers approach this model, although only approximately because their output impedance is typically higher. Other tube amplifier's, with even higher output impedances, fall into the power paradigm category.

As Ralph's paper mentions, a significant downside of voltage paradigm amplifiers is that they typically (but certainly not always) require more feedback than power paradigm amplifiers, increasing the well-known side-effects of feedback.

In a power paradigm amplifier, the output impedance is much higher, for instance 4 ohms or more in the case of many of Ralph's designs. That will cause both the voltage that is seen by the speaker and the current that is drawn by the speaker to depend on the impedance of the speaker at the particular frequency that is present. The higher the speaker's impedance at the particular frequency (or frequencies), the more voltage it will see (because it represents a greater fraction of the total impedance that is in the path, meaning its own impedance plus the amplifier's output impedance), but the less the current that will flow (because the total impedance in the path is greater). Since, if we neglect the effects of inductance and capacitance, power is equal to voltage times current, the power that is delivered to the speaker (as opposed to the voltage) will remain fairly constant as a function of variations in the speaker impedance.

As I said, most speakers, especially box-type speakers, are designed with the expectation that they will be driven with voltage-paradigm amplifiers. But Ralph's paper includes this statement:

Loudspeakers that operate under Power Paradigm rules are speakers that expect constant power, regardless of their impedance. Examples include nearly all horns, ESLs, magnetic planers, a good number of bass reflex and acoustic suspension designs. Horns, ESLs and magnetic planers do not get their impedance curve from system resonance and so benefit from a constant power characteristic and indeed, many of these speaker technologies are well-known to sound right with Power Paradigm amplifier designs.

So that is some background. Returning to the original question, I think all of this should make clear that a tonal imbalance can result from a paradigm mismatch between amplifier and speaker, such as the excessive brightness that would undoubtedly result from using a power paradigm amplifier (high output impedance) to drive this particular speaker (4 ohm impedance in the bass, 8 ohm impedance in the treble). But a voltage paradigm amplifier (near zero output impedance) would deliver essentially the same voltage into both the 4 ohm and 8 ohm impedances, which is presumably the expectation the speaker was designed based upon (or it would not sound right with just about any solid state amplifier). And the ability of the amplifier to deliver twice as much current into 4 ohms than into 8 ohms has no direct relevance to tonal balance; its main relevance is to maximum volume capability. Although, of course, for any of many other possible reasons one voltage paradigm amplifier may sound different with the particular speaker than another, and it stands to reason that an amplifier that can double current into 4 ohms will, everything else being equal (which of course they rarely are), be more comfortable dealing with a speaker like this.

I'll add in closing that although I haven't read Harley's book, I have read a lot of his writings over the years in TAS and Stereophile, and I suggest that you do not exclude the possibility that anything he says of a technical nature may be flat-out wrong.

Best,
-- Al

Again, thank you for all your input and your time doing it. Blindjim, The situation with me and my gear is this. Several months ago, maybe 6, I decided to get back into the hobby. I had an old NAD preamp tuner and a cheap audiosource amp3. I still had my KEF 103/4 speakers from 20 years earlier and decided to buy everthing new (to me). I started reading the forums here and several audio reviews to try adn decide what I should buy. I know this isn't the best way to put a system together, but we just don't have the retail stores around here in Seattle like we used to. And, although I grew up here and have many friends I don't have a single one that's cares about gear or music for that matter. This is why after several months of listening to my system and continuing to read what many of you have to say on these forums I decided to reach out and ask for help. I will say that I did not have the brightness problem with my old set up. That being said, the system was very closed in and I'd say even muffled to some degree. I can say one observation is that I did play my NAD with the Butler amp and also my surround sound Denon 990 and the system was not bright. But it was also very closed in without a lot of detail and the Denon just sounded bad. When I added the Capri which was slightly used it also seemed closed in. Then after a couple of weeks bam! While I was listening it just completly opened up. That's when the brightness started. So much for me not believing componants break in. Yes, the sytem is brighter, but I can hear everything now like a veil was lifted. So, my thinking is that any quality pre would probably do the same thing.
I do listen to my system pretty loud around 70 to 95db depending on my mood and the music I'm playing or how much I've had to drink :). And yes, I do have to turn up the system to get the speakers to fill the room, otherwise the music just feels like it's not forward or engaging enough. I've thought about a sub and also wondered what another speaker that dives a little deaper in the base might do for me (Aerial 10T?). I expected the 7B to do the job, but they seem to mostly do a really good job at tight fast base which I do like. TVAD, I've been contemplating raising my speakers up already, but for a different reason. Mabe I can solve two problems at the same time. The ends of my two identical couches are very close to the front of the speakers and yes, this does effect the base to some degree. I've moved the couchs out of the way along with my coffee table and know what the differences are so I didn't bring that into the mix here. That is not the heart of the problem. When lifting my speakers up, are there some general rules to follow? Do I use wood covered in carpet, concrete, how high do I lift them ect? I really do want to get to the bottom of this, I hate a bright system. I'd rather go the other way and lose a "little" detail. Thank You All Again!

Gregfisk

I noticed great extension using the butler multi ch amp with my receiver, still greater with only my BC DAC 3, and when attached to my tube preamp and better cabling, it was more than intriguing. Piercing, etched, glaring, or hard sounding, it was not… not with any pair of speakers, or pre/pro combined with it. Even using my most modest spkr cables and sans conditioning on my tuffest spkrs, it sounded very nice.

On every other occasion however, it was fueled by an upscale power cord, and got its power via a Running springs Haley power line filter which was inturn, supplied by yet another upscale pc. The pc’s in my case certainly can be migrated about to add or subtract their audio influences from time to time, but I like the Elrod Sig III as supply cord for the Haley… and the older red Python VX for the revolving digital items. The Gold dragons drive SS amps and my DD 15…. Usually. PCMV.

I run the rec and tube pre directly from a dedicated 20 A ckt. Sources, are provided via either the Haley or a PS Audio duet and as well, Taipan helix’s most often or a Nirvana pc, or Voodoo Tesla II. OEM power cords around here stay in the box they came in or find their way onto a cable box, VCR, pc, etc.

Those wire choices I submitted earlier are as just, but on perhaps a more amenable front, financially. I’ve jotted down my thoughts here on the ‘gon in reviews of Voodoo power cords, and others. Not sure about the Taipan helix’s though. They are a more up front higher resolute and detail oriented cord which offers a more front row sound stage, and introduces a harmonic rightness that is very attractive when used on tube gear especially.

The Voodoo Black has an expansive sound stage and yet again, that near front row seating scenario, yet is vastly smoother though still allowing for great detail. Both work everywhere and with almost any scenarios save for use with digital masking cords with high capacitance. It will also seem to lower the overall timber range by nearly an octave, thereby adding more bottom end and relieving an attention getting top end. The Tsunami pc is about as smooth as is the Voodoo. A Cardas or it’s doppelganger, the Mongoose could also be effective for you.

I’d have mentioned the Shunyata Python VX, and helix VX but they range upwards of $550 - $700. With newer models just now out, these prices might drop more so quite soon. For more info on these or other pcs, just PM me. Same for cables that might help your rig or have some interest to you.

Just as fitting together a systems devices, the same process is had for mixing cabling, or even choosing to enlist the same brand cabling throughout.

AS for the aerial 10Ts… I’ve heard even from dealers that didn’t sell them, they were great speakers… then. Maybe now too. Albeit, a close look at their numbers might find you in need of some other power supply for them… I’m not so familiar with them I can recall their specs just now. Your amp should be fine I guess with 10Ts.

250wpc @ 8 ohm amps are probably the place to begin building a new rig. Wether they double down at 4 ohms or not, isn’t nearly the ticket. It’s the amount of reserve power they have on tap. Without enormous power reservoirs apparent in the construction of an amp, to gain needed headroom, the ability to double a rated power output very well may be required. BAT illuminates this reserve power ideal as best as any in the industry. The BAT vk 500 SS amp that makes 250wpc @ 8, is likewise to the butler’s output of 400 @ 4…. Yet the power banks are vastly different, with BATs being far bulkier. I know of some which use the vk200 (100wpc @ 8) to drive panel speakers that are quite power hungry.

Sonically the 500 and 5150 were much more alike, than different.

To understand better some terms I use frequently, openness for me, is when I point to the separation of images in a sound stage. Closed in, similarly but as it’s opposite. Expansive sound stages by their nature open up the recreated venue.

Power cords do primarily two things… formulate a sound stage better, and refine the sound itself, in many cases. The Darkness terms associated with BAT I think revolve about direct comparisons, and a lack of attention to adding the proper wires to them. For ‘dark’ as I understand it equates to muddy or a lessened ability to discern facets within the reproduction. BAT amps aren’t dark… and their preamps definitely are not.

I’ll say this and split… if effecting a cure for the situation and the amount of money available to do it is finite, and overt room treatments a ‘no no’, look into razing the bar commensurately with your cabling, to a more appropriate level to that of your current system components. There’ll be a lot less thinking about replacing gear thereafter… ‘till the mood strikes once more. Rugs and plants can go a long way to helping a room sound better too.

TVAD

Sure.

The point you miss is simple…. Everyone else is not you. Do not have your resources. Inordinately high standards…. Or personal temperament. On your account, one could spend on just 3 amp in home demos, $600, if the entire burden of shipping was the demoees, and only a 10% sir charge was assessed on amps retailing for $1000.

…and perhaps be no better off. Not to mention having to use aural memory predominately thru the series of trials. Even with wizard like skills of coordinating shipping and arrival times, once 4 amps are in house there’s the needed settling in and switching about which can be quite confusing. Unless of course, one offering initiates some profound auditory epiphany. Let alone there be some cooling off time following that event which could further confuse things… and then we’re back to “Well, what if I had put a so & so pc on that whosit, instead of the ABC it had on it then?”

But it does sound good on paper to serve it up as an option I suppose. It’s just that I find it costly and possibly providing no true answer once endured.

I feel until a system and/or room is stabilized in fact or just pretty good, not only does one not really know what they have on hand, nor will they by migrating in & out other major devices so prematurely.

How is your own cabling, conditioning, and power cord situation, BTW? Still using OEM pc’s and entry level or DIY cabling? How about platforms and those aluminum cup & ball (Oreos?) footers?

I recalled you saying frequently some years ago “Everything matters. Has your position on that changed now?

I saw the other day a thread where you said cabling would not be the way you would attend to a speaker problem regarding some Wilson Sophias and the Ops designs on upgrading away from them. There in that same thread was a follow up which pointed out how much change was made to the Stereophile reviewers thoughts by making some cable changes. That resolution came after other major items had been moved in and out, without notable success. Making some ‘suggested wire changes the results were well improved and the reviewers stance took on a complete about face.

http://forum.audiogon.com/cgi-bin/fr.pl?cspkr&1249339357&openmine&zzBlindjim&4&5#Blindjim

‘course, you remain consistent. I’ll give you that… as singularly authoritative as it may come across now and then. IMO

Ease up Grant, you ain't all that.