We should reject hard-to-drive speakers more often

@steve59,

What speakers do you have?

Mike

there are so many things we should reject. Not sure hard to drive speakers are at the top of my list. 

Just found this thread again.  I completely agree with you about your post Sounds_real!  Too many folks read specs etc… and forget to put a true ‘system’ together.  As long as you have the system to match your speakers, you’ll never have to worry about specs and how hard or easy a speaker is to drive.  

I’ve always marveled at how many folks just assume speakers with lower efficiency ratings assume they are hard to drive etc…, but in fact they may end up being easy to drive in real life.  

As long as you have the system to match your speakers, you’ll never have to worry about specs and how hard or easy a speaker is to drive.

Well, how exactly do you match those without a lot of trial and error, or social knowledge if you can’t actually rely on specs?

As a consumer this seems like a ton of work. Sometimes this work is a lot more because vendors ( looking at you, KEF ) completely mischaracterize their products.

Why do some tube amps have the power to drive apogee scintilla and full range speakers, the specs certainly don't tell you this would work.

What tube amps ( tubes used in the output stage ) can " adequately " drive 1 ohm Scintillas ? I am not aware of any, and would like to know, so I may sleep better tonight. My best, MrD.

Eric, that's why I use dealers and purchase from them. They are the ones who do the work as they carry what will work together best and what will be reliable (they can't make money when things break down).  

Too often folks just buy 'top rated' this or that or component of the month.  I found a speaker I love and then I listen to the dealers as well as what the manufacturer uses and it's a start.  

When reading posts online, you see where spec defy reality.  There are just too many factors like room size, ones own hearing, what's in the room (room sound) etc...  Yes, trial and error is a huge part of this hobby isn't it?  I may read threads and mags, but my ears are always the final factor.  Just because a high efficiency speaker seems easy to drive, that doesn't mean it the electronics will sound good with them, just that they can 'drive' them.  I'm not an engineer, nor do I need to be to know what sounds good.  

I don't have the money for trail and error purchasing and selling like so many seem to have (or they do it and keep loosing money on the treadmill) so I audition before purchasing.  It's very rare that I don't and that includes my high priced cables and cords.  That's just me. We all have our own way to purchase and I'm not dissing anyone else's way.  It's all good and it's still all about the music for me.

If they sound good, get amps which are stable for 2Ohm and below!

close thread 

My speakers are Kef Blade 1. When my 250/425 wpc amp drove them to realistic levels I thought I was golden, but as time passed and I found low volume listening was boring I decided to borrow a more beastly product and the Mc 611's are staying. I think of the Horsepower vs torque analogy but have no clue what amp measurements would apply? 

What tube amps ( tubes used in the output stage ) can " adequately " drive 1 ohm Scintillas ? I am not aware of any, and would like to know, so I may sleep better tonight. My best, MrD.

If you use an outboard device like the ZEROs then its possible.

Ralph, so the answer is = none. My best, MrD.

Ralph, so the answer is = none. My best, MrD.

Back in the early 90s, TAS did a review of our MA-1 OTL amplifier. OTLs are not known for driving low impedances. The reviewer, Steven Stone, had a set of the old Apogee Full Range speakers, which were 1 Ohm. At the time we made an outboard autoformer called the ZMusic (similar to the ZEROs) that we installed between the amp and speaker- the ZMusic had a 1 Ohm tap. The result drove the Full Ranges quite well- despite the impedance, they otherwise were a resistive load and didn't need a lot of power. Steve commented it was the first time he had ever heard the speaker with a tube amplifier. 

in your experience ralph, when an autoformer is used to better couple tube amps with lower impedance speakers, is there a meaningful sonic penalty? seems to me that what is happening is many many more metal windings are being placed between tube amp's built in transformer (leaving aside the otl’s for a moment) -- and so my guess is that there must be more of the classic wooly, expansive, slightly echo-y transformer sound that is introduced into the music, more or less....

of course, this point and my question is moot for speakers that could never be driven by the tube amp in the first place, but have you done an experiment with a more ’normal’ higher impedance speaker... then adding the autoformer ... then trying hearing the sonic change from the additional transformer present in the chain?

just curious

@mrdecibel  there are a few tube amps that can power the apogee scintilla and full range, most of them have 1ohm taps. There is a guy that used to post on the apogee forum that is powering his apogee full range with Tube Research Labs amps, four monoblocks with 1200 watts total, and he has owned quite a few of the usual suspect solid state amps that are supposed to be used with this type of speaker. He says the tube amps do the best job.

@jon_5912 Wrote:

 High power class D amps more than make up for the difference in dynamic contrast between low and high efficiency speakers. 

In my opinion, a high powered amplifier that can drive lower impedances will never be a proxy for a speakers lack of true efficiency. 

Mike

I have been around the block with Apogee speakers back in the day, including the Scintilla ( I actually owned, for a year, the Duettas ). My question was, as stated, " adequately " drive? I am not fond of tube amps ( low / poor damping factor ), which is a shame, as I own horns. The times I used tubes for mids / highs, and ss for bass, I always was aware of the " transition " between the two. Listen, I have always said, " whatever the listener enjoys, that is fine. I like what I like, and I don’t like, what I don’t. My best, and enjoy ! MrD.

@ditusa wrote:

In my opinion, a high powered amplifier that can drive lower impedances will never be a proxy for a speakers lack of true efficiency.

I fully agree, Mike.

@mrdecibel wrote:

The times I used tubes for mids / highs, and ss for bass, I always was aware of the " transition " between the two.

Even via my horn hybrid, actively configured main speakers using different SS amps for the top horn section (~600Hz on up) and bass bin it doesn’t go unnoticed that they "speak" slightly differently when compared to using two identical amps here, not least when the identical amps are bi-amped vertically. The difference is likely somewhat more subtle vs. the scenario of tubes + SS you’re describing, but it goes to show there are points in coherency to gain with extra attention invested here.

The SS amp chosen for the subs below ~85Hz is less critical wrt. ultimate coherency, but to my ears what is critical in this region is choosing an amp that doesn’t go totally bonkers with a damping factor in the thousands as a means in itself, but this is obviously also a matter of proper subs-amp-room matching and what sounds the most musically full and natural here, or whatever one finds appealing. Overly damped (i.e.: "tight") bass isn’t natural bass to my ears, nor is the inverse scenario - it’s certainly about finding the right balance in relation to one’s (p)reference and context.

@erik_squires wrote:

At some point significantly below Xmax I believe there begins to appear evidence of compression, both within the FR and distortion.

In addition to thermal issues this would only stress the importance of headroom, and also as a phenomenon somewhat equivalent to thermal modulation as an effect that has sonic implications well before the typically assessed limits, both thermally and mechanically. These "grey areas" definitely need more attention. 

@phusis  I couldn't agree with you more about overly damped bass.

@phusis Wrote:

Overly damped (i.e.: "tight") bass isn’t natural bass to my ears, nor is the inverse scenario - it’s certainly about finding the right balance in relation to one’s (p)reference and context.

 Couldn't agree more! See article below:😎

Mike

http://diyaudioprojects.com/Technical/Papers/Damping-Damping-Factor-and-Damn-Nonsense-Floyd-Toole.pdf

I give you permission to reject hard to drive speakers, on my behalf. Keep up the good work.

Thinking about this thread for a while and I realize I should have inverted the headline.  What I wish I had written was:

We shouldn't praise speakers specifically because they are hard to drive.  A speaker that is discerning of amplifiers because it is hard to drive is not necessarily any good at playing music.

My bad.

in your experience ralph, when an autoformer is used to better couple tube amps with lower impedance speakers, is there a meaningful sonic penalty?

@jjss49 IME a tube amp often won't deal with low impedances, particularly something like 1 or 2 Ohms. In those cases, there are no tradeoffs- the autoformer makes it possible to drive the speaker where it was not possible before. Its when the speaker is a bit higher impedance (4 Ohms or slightly more) where you might encounter tradeoffs.

BTW this holds true for solid state amps as well. Even though they might easily double power into a lower impedance, that's not the same as saying they sound their best doing that- and you can also measure the increased distortion. Paul Speltz, the guy that makes the ZEROs, has a letter from Steve McCormick (who makes very competent solid state amps) that says exactly that: it sound better driving 4 Ohms thru the ZEROs than doing it directly, despite being able to easily double power into 4 Ohm from 8.

@atmasphere

i completely follow what you are saying... i actually used paul’s zeros years ago when i was trying to run maggies driven by roger mojeski’s rm9 tube amp... you are right, when the amp really can’t handle the load, the autoformer poses no tradeoff... its autoformer or no music...

i was curious on the sonic degradation if used on an easy to drive speaker

also, i had never thought of using them with solid state amps! makes perfect sense, the autoformer provides any amp with greater electrical 'leverage'  irrespective of amp type...  ok i am going to try to find those zeros in my storage closet this weekend, maybe i still have em!

@ditusa --

Very good article by Floyd E. Toole - thank you :)

@phusis :

You're welcome, glad you liked it :-)

Mike