[David Ellis]

Dave, do you think the 15 watt Class A amp could work effectively with 1801's despite their low power rating. I have read that seem to "punch above their weight" in listening tests.

Well, marginally.

The basis for this answer is a listening session with an El84 push pull amp having about 15 watts.  It was VERY surprising.  I never thought 15 watts from an amplifier could do that.  The spl was more than I needed.  

However, your amplifier is Solid State, and it will not clip as gracefully.

I think 15 watts will perform... okay, but you will not get all the spl from the 1801 possible.  For 98% of listening, you will not need this spl IMO.  I look forward to your project completion and any comparison with the 55wpc AKSA.  

Dave

[konut]

1. I agree!
2. No, I have not heard any of these speakers
I have no way to confirm it, but I suspect that the NAO and Orion are able to acheive higher SPLs before compression. The fact that the NAO and Orion utilize active elements lead me to this conclusion. Up to a certain SPL I do not doubt your contention that these speakers sound essentially the same. There are many roads that lead to Rome. Some enjoy the ride on the straight road with a cushy suspension, while others prefer the road with the hairpin turns with peaks and dips in a sports car with a stiff suspension.

I suspect that E.P.'s less than stellar experience with his active experiment was due to the equalization component of the passive crossover were not addressed. I can understand why these parameters are not openly published as Mr. Murphy's talent is worth something and giving away proprietary info like this might result in reduced sales.

A  deviation off topic while I've got your ear. Have you ever considered,  experimented with, or actually built any of your cabinets with, Baltic Birch ply? Would you consider selling your speakers without the crossover with dual binding posts wired to the appropriate drivers?  (Without warranty and at a reduced price, of course)

[David Ellis]

I have no way to confirm it, but I suspect that the NAO and Orion are able to acheive higher SPLs before compression. The fact that the NAO and Orion utilize active elements lead me to this conclusion.

Yes, this would theoretically be true.  It would follow the many other things about active crossovers are also theoretically true.  For me, this remains... just good theory.

There are many roads that lead to Rome. Some enjoy the ride on the straight road with a cushy suspension, while others prefer the road with the hairpin turns with peaks and dips in a sports car with a stiff suspension.

I am a detail guy, and enjoy every drop of nuance and detail from my system.  My congenial response is...

There are many roads that lead to Rome. Some folks enjoy the ride on a well maintained public highway, while others would rather travel on a toll-road and pay way to much money for their trip.  After all, there is significant theory conveying the toll-road provides a much more gratifying experience.  

I suspect that E.P.'s less than stellar experience with his active experiment was due to the equalization component of the passive crossover were not addressed.

The passive crossover addresses the response in the crossover region and has no impact at 150hz.  And, how would he address equalization and phase around the 150hz active crossover?

Before spending 100-200 hours at the measurement bench, I knew what sounded "right" or "wrong", but didn't really know how to change matters to obtain a "right" sound.  Amplitude and phase get very messy.  At this point, several years later, I would have about a 25% chance of being able to able to obtain perfection when tuning an active crossover & equalizer by ear.  This 25% is my guess only.  I suspect the chances for an unexperienced layperson would drop considerably.

IMO, the real advantage of using an active crossover for @ 150hz crossover is room interaction and listener preference.  The room loading at low frequencies changes dramatically depending on the room characteristics.  Listener preference for bass level also varies considerably.  Using an active crossover enables the user to adjust for both of these things.  With some measurement in my shop during initial implementation and a pre-set phase & some equalization, the right levels could be obtained.  These levels could be altered in the users home.  There are other ways to obtain these results via magnets and resistors too.  Magnets and resistors are cheaper and less complex.

A deviation off topic while I've got your ear. Have you ever considered, experimented with, or actually built any of your cabinets with, Baltic Birch ply?

I built some cabinets with birch ply for bracing.  I think (?) there was a small difference in the "knock" test, but this was very slight.  I couldn't hear any musical difference.  Birch ply is considered to be the "cats meow" for cabinet material, but I haven't found anything objective about is superior resonance/flex/MOE properties compared to MDF... So, I keep using MDF.  I also tried ceramic tiles, cement boards, sandwich construction...  Do you have a source for a good test using Baltic Birch?  My test was surely not comprehensive.

Would you consider selling your speakers without the crossover with dual binding posts wired to the appropriate drivers? (Without warranty and at a reduced price, of course)

Hmmmm, no.  

[konut]

On your website, on your SPL page, you make the comment that, and correct me if I'm wrong, the 1801' start to compress after 90db. While that might be acceptable for some, it might not be acceptable to others. By all accounts your customers greatly enjoy your speakers and theres nothing wrong with emphasizing one aspect of performance over another.   You seem to have created a going business for yourself in a very competetive industry. You are to be lauded for your efforts and uncompromising standards when it comes to the products you produce. However you have to recognise that not everyone places the same emphasice on the performance parameters you have chosen to showcase in your products. Whats good theory for you, might be standard pratice for others. As theres no free lunch others have made different design choices that place other parameters at the top of list sacrificing other aspects. Maybe, for you, active biamping is an unneccessary complication in the reproduction of sound but for others it allows aspects of reproduction that you dont seem to feel are important. Thats fine. Your unwillingness to accomodate those people limits your market and makes you appear to be close minded. Thats okay too. You might want to mention on your website that you dont encourage or endorse active biamping and that those who do, really dont know what they're talking about. It would help to define your market and thus you could better focus your efforts on those who agree with you thus obviating the need for discussions like this.

[David Ellis]

On your website, on your SPL page, you make the comment that, and correct me if I'm wrong, the 1801' start to compress after 90db

First, there are many ways to measure SPL.  This is an in-room AVERAGE with a pop-music track.  It's not an instantaneous peak impulse at 1 meter.

Second, the only people who question/complain about the lack of spl from the 1801 are those who have never heard it.  NONE of my @120 customers have mentioned the lack of clean spl potential from these speakers after having them in their own living room.  Quite the opposite sentiment has always been conveyed when the issue of in-room spl is discussed.

Third,  I do understand 90db in-room is not bar-room or rock concert level spl, but it's enough to damage hearing (according to OSHA) for long duration exposure.

Thats fine. Your unwillingness to accomodate those people limits your market and makes you appear to be close minded.

Many thoughts.

1.  Accomodating people takes time.  Maybe your time "grows on trees" but my time doesn't.  I simply don't have time to accomodate every idea or customer whim.  IMO, such customers need to pay commercial folks a commensurate amount for the high degree customer-maintenance needed to make them fully happy. I have spent a few years wanting to develop other projects that other customers said they are willing to buy.  But, my life is full.  I have a very full-time job, wonderful wife and 2 kids.  At the prices I charge, my work is charity.  If you wanted, and others wanted to pay me 3x$ to 4x$ for my time maybe I'd change vocations, but... even at this rate, I'd be taking a cut in pay from my "day" job that I truly love.  

2.  The purpose of this discussion forum is to address any issues of concern the general populus feels necessary.  When future questions about bi-amping arise via email, I will direct folks to this forum.  I could certainly add my thoughts on bi-amping to my Rhetoric section, but they are already addressed here.  And, my ideas expressed here are subject to your scrutiny.  I think this is a perfect way for an outsider to really see both sides of the argument - unedited.  Further do you find any comments about bi-amping on the Kharma loudspeaker page??  

3.  There is a plethora of bad information in hifi.  There is also some very good information that doesn't yield results.  Speaker wire companies are probably the biggest perpitrators.  I vowed several years ago to maintain complete integrity in my work, in my family, and in my hobby.  In my hobby I have not, and will not sell anything having litte/no audible impact.  Such is true with the Audio Cap Theta.  Sure, it's better, but... only a very small amount better.  It's mostly just different to my ears.  Sure, I understand the film & foil discussion, but I simply ain't gonna' purvey stuff having little/no audible value.

4.  Somewhere in Politically Correct jargon, having an opinion about something labeled a person "closed minded".  Well, if that's how you label my opinion, I fully accept that label.  I do have an opinion about bi-amping and it's clearly expressed above.

5.  I ordained the 1801 to have world class midrange, world class highs, and tolerable bass to 40hz at a spl louder than a mature gentlemen would use for extended listening sessions.  I believe, this goal is achieved.  I also cater to folks enjoying classical music and those who enjoy detail rather than coloration.  This being said, probably 1/2 of my customers are not die-hard hifi symphony attendees.  These folks enjoy my speakers too, but my best "fans" are those guys with very good gear, and very good ears.  Yes, this does make my audience narrow.

You might want to mention on your website that you dont encourage or endorse active biamping and that those who do, really dont know what they're talking about.

I never said/wrote this.  Quite contrary, I have conveyed repeatedly 2 things:

1.  The theory of bi-amping and active crossovers is very good.  Indeed there is good theoretical validity for bi-amping.

2.  I can't & didn't hear the impact.

You seem to have created a going business for yourself in a very competetive industry.

Well, my wife (a CPA) has conveyed on several occasions that business actually make money  

On a personal note... this string has become somewhat long for me.  I am not very fast at the keyboard.  I'd be glad to address any futher discussion via telephone.  I'll have time this evening if you wish to chat.  I'd be happy to call you and we can use "my dime".

402 991 8528

[konut]

For all of you following this thread, I had a most enjoyable conversation last night with David. We talked about many things and got a feel for each others sensabilities. While we still disagree about a few thing, we found many more areas of agreement. Make no mistake, the products that David handcrafts offer tremendous value and superior quality and compeat with products costing many times the price. I'm glad he offered to speak with me as theres nothing like a live voice to really communicate. So much better than typing!    

[David Ellis]

Indeed, we had a most excellent chat.  I learned that Konut has a plethora of experience with active crossovers starting in the 1970s.  He mentioned several projects, including one using a JBL 2020 (?) woofer and some Bose full range drivers (for mids & highs).  There were several other projects too, but I don't remember exactly what drivers were used.  In all of this we found significant agreement.  

I think we continue to disagree about what happens when active crossovers are used with the SOTA drivers of today.  The difference being that I have some audible exposure with this    .   Konut has none.

All in all, it was a very good chat.

[David Ellis]

Interesting topic. I went ahead and tried an active crossover because I was curious about this subject. So far, I am of the impression it really makes a significant improvement.

Were you able to measure the results after the bi-amping?

[timbley]

Interesting topic. I went ahead and tried an active crossover because I was curious about this subject. So far, I am of the impression it really makes a significant improvement.

Were you able to measure the results after the bi-amping?

No, I don't have any measurements to work with. I have an RTA on my Behringer DXC 2496 (edit: deq2496), but it's not showing me anything I can point to and go Ah ha! It shows flat frequency response once I get the drivers matched and EQ'd. I'm pretty sure it plays louder now at any given volume setting.

I got a JVC F10 to try out earlier this week, and it seems to have better bass and a warmer sound. The RTA doesn't reveal any of that.

I've now added a second JVC F10 receiver so that each of the 10" midwoofers can have it's own amp channel. I'm of the distinct impression that this has improved the clarity and depth of the sound yet again. It seems blatantly obvious to my ears. But I try not to under estimate the power of suggestion. Just knowing I have 300 watts going to each channel now with no leaky crossover circuits may have an effect on my perception.

I've not told my girlfriend what I'm up to. She just listens to her music however I have the stereo set up. She hasn't said anything lately about the improved sound quality, which is disappointing to me.

[David Ellis]

I was under the impression you were bi-amping the 1801s??  It appears you are working with something else.  What are you working on?

I've now added a second JVC F10 receiver so that each of the 10" midwoofers can have it's own amp channel.

Then...

Just knowing I have 300 watts going to each channel now with no leaky crossover circuits may have an effect on my perception.

Have you measured how many watts you are dropping across the driver terminals?

She just listens to her music however I have the stereo set up. She hasn't said anything lately about the improved sound quality, which is disappointing to me.

   This is funny, but often true.  Most women have much keener ears than men.  My wife notices changes and improvements almost immediately.

Also, is your 300wpc JVCF10 Receiver a Home Theater unit?

[Kevin P]

3. There is a plethora of bad information in hifi. There is also some very good information that doesn't yield results. Speaker wire companies are probably the biggest perpitrators. I vowed several years ago to maintain complete integrity in my work, in my family, and in my hobby. In my hobby I have not, and will not sell anything having litte/no audible impact. Such is true with the Audio Cap Theta. Sure, it's better, but... only a very small amount better. It's mostly just different to my ears. Sure, I understand the film & foil discussion, but I simply ain't gonna' purvey stuff having little/no audible value.

Ha.... I commend you!   I sell several things that I feel have little or no audible value.   Some of them are cosmetic and some of them are just tweaks.   My take is that there are some things that people want that may not hold any value for me, but hold some value for them.   Where integrity comes in is that when people ask you if an item really makes an audible difference you tell them the truth, as you see it.    Selling wire can becomes an ethical minefield.  I have no desire to argue the audibility of a particular wire or tweak with my customers.  Most of them come with preconceived notions and a some come genuinely seeking my advice.     I just tell them if I can or cannot hear an audible difference in my limited experience and try to guide those who are receptive to the best solution for their given situation.  

Hope you don't mind me jumping in on your thread.

[David Ellis]

Selling wire can becomes an ethical minefield.

Yep for sure     And... It ain't that all wire is awful - oh no. There is certainly some very good wire, and wire that makes an improvement.  However, in "wire world", Dave Ellis thinks the marketing (and resultant cost) severely outweigh the impact.  

BTW, I visited your site - it's very well arranged and looks very nice!!

[timbley]

I was under the impression you were bi-amping the 1801s??  It appears you are working with something else.  What are you working on?

 This is funny, but often true.  Most women have much keener ears than men.  My wife notices changes and improvements almost immediately.

Also, is your 300wpc JVCF10 Receiver a Home Theater unit?

I'm using Klipsch RF-7s, which have two 10" mid woofers in parallel and a horn tweeter. I don't know how many actual watts are going to the speakers, but I'm not playing them that loud so I shouldn't have said 300 watts actually going to the speakers, but 300 watts of amplifier power, with 100 watts individually available for each driver. Others say this amp may be a little over-stated, so it may be more like 40 watts of available clean power going to each driver, which puts us down to 120 watts/ channel. Really, the improvement in audio quality I'm hearing isn't so much an ability to play loud, as a increase in midrange clarity, more convincing imaging, and better clearer, deeper bass that gives a better sense of expansiveness. Classical music has never sounded anywhere near this good before the active crossover, and especially with the 10" drivers each getting their own amp channel. It's beautiful.

The JVCF10 is a home theater unit with a "hybrid feedback" digital amplifier, actually 6 of them. I decided to give it a try since many on this forum feel that it produces excellent sound through it's analog inputs, and can drive difficult impedance loads well. My RF-7s are said to be difficult for amplifiers, and my Behringer crossover only gives me analog output, so I figured for $159.00 I ought to try it. So far I am highly impressed wtih it. The only thing I don't like is that it has a fan that likes to be on all the time. It's not a super big issue, because the fan is pretty quiet, and it's not like I have a super silent listening area.

Yes, my girlfriend has good ears, and I like to hear response from her when I think I've made something better. But she doesn't really pay much attention to the audio system. I think I've made so many changes lately that it's just something she ignores now. She makes fun of my audio habit frequently.

[David Ellis]

The agreed industry standard rating sytem for Home Theater amplifiers is with 1 (1) channel driven at a time. Hence, a 300wpc stereo amplifier will safely drive 1 channel at 300wpc.   The agreed (and enforced) industry standard for Stereo amplifiers is 2 channels driven at a time.  Hence, a 300wpc HT amp when used in stereo will objectively push the same juice as a 150wpc Stereo amp.

I fully believe and agree that a "better" active crossover system will likely improve upon most commercial passive crossovers.  This is due to the very mediocre parts quality, parts count, and design of the OEM passive crossover.  Heck, the parts quality and design of many commercial "hifi" speakers is quite mediocre.  I once owned a small European "hifi" speaker that cost $600 and used electrolytic capacitors behind the tweeter.  I have heard similar stores in commercial "hifi" loudspeakers at $1500.

Do you know how to roughly calculate the Wattage used in your spekers using a multimeter?  Do you have a multimeter?  Do you want me to explain this.  The math is quite simple.

[timbley]

Yes, I have a little Radioshack multi meter. I'm not sure how to use it to measure power. I'd be interested if you wanted to tell me more about it.

I used it to try to test impedance on the RF-7 at different frequencies by running it in series with the woofer, and measuring the voltage drop across the resistor compared to the drop across the speaker and the resistor. My understanding is that a good amp will hold a constant voltage at any given frequency as  long as the volume is the same. I noticed the Panasonic wasn't able to do that with the RF-7. Either that, or my multi meter is only so accurate. I also noticed that there were some points where the resistor was using up most of the voltage drop, telling me that the speaker had a low impedance at those frequencies.  I didn't bother to calculate what it was, but I guessed it was around 1/3 of  9.7 ohms, which correlates to other peoples measurements of the RF-7
I found that my multi meter quit working once the frequency got too high.  I can't remeber what, but it was less than 9 khz. Above that the AC voltage readout went down to close to zero.

I haven't tried any of this since I tri-amped my speakers and switched to the JVC amplifier.

[David Ellis]

Yes, your measurement quandry with the RS multimeter really is strange.  I can't help you there.

First, the math.

Current (Amps) = Pressure (Voltage) / Resistance (Ohms)

Watts = Current(Amps) * Pressure (Voltage)

First, with no load, measure the resistance across the terminals of your speakers.  Yes, I know this is only an approximation because of the impedance swings, but it will provide a good "base".

Second, with your speakers being driven at a comfortably loud spl with music, measure the voltage drop across the same set of terminals on your speaker.  The peaks will be 5-10x higher depending on program material.  I used pop music.

Third, plug the numbers into the simple formulae expressed above.

As an example.

Resistance = 6 ohms

Voltage drop = 6 volts

Current (Amps) = 6volts / 6ohms

1amp = 6volts * 6ohms

Watts = 1amp * 6volts.

Again, this is only an AVERAGE.  Peaks will be 5-10x higher.

Dave

[timbley]

I measured about .4 watts going to each mid-woofer. Roughly 1.5 volts into  5.7 ohms. I played some "Etnica Planet X" trance, with constant driving bass and lots of sizzly sound effects. My girlfriend likes that stuff, and was quite happy to let me turn it up as loud as I dared. It was loud, and I decided I wanted it turned down before she did, imagine that! When me and my gal are dancing, I like the music turned way up. But if I'm just sitting there listening, I don't need it so loud.

The F-10s were at 22 on their volume level. I think it goes up to 40, which would be insane. It's a lot louder at 20 than 15. I'd be afraid to take it up to 30 for fear of getting arrested or breaking a window out.
At .05 watts per driver I'm hearing fully the benefits of going the active driver route. It's just sparkling clear and sweet, and the bass is fully developed and smooth. So this leads me to believe that the same benefits could be gained from an amp as little as perhaps 5 watts per speaker channel at the volumes I listen. It also makes me wonder about the meaning of amplifier power. Perhaps an amp that's rated at 100 watts per channel may not really do it's best at anything above 1 watt, but it will pump out noise of some kind up to 100 watts. Another that's rated at 15 watts per channel may perform beautifully all the way up to it's rated 15 watts. I don't know.  My friend who used to do pro audio for live events, and who got me interest in horns, is of the opinion that you never want your amps averaging above 1 watt.

BTW I looked at your Ellis Audio web site. I have no problem believing that you offer an excellent sounding speaker, even without reading the reviews. The frequency response on that tweeter is amazing. My RF7's horn tweeters need quite a lot of EQ to get them flat. From 2 to 20 kHz, they are more like plus or minus 7 db with a big arching rise and fall from what my RTA is telling me. Some kind of EQ is an absolute requirement.

[David Ellis]

It also makes me wonder about the meaning of amplifier power.

I wonder about this too.  I have an old Kenwood 2 channel receiver rated at 125wpc.  It sounds pretty good, but my old Bryston 3b-ST has way more power than the Kenwood.  The Kenwood subjectively clips and distorts very early (maybe 40watts?).  I don't have a tangible explanation for this.  I believe amplifier specifications are actually tested and enforced.

In this regard my only explanation for the subjectively lesser power driving ability of consumer grade amplifiers is cheap electrolytic capacitors that dry quickly.  When NEW these power supply capacitors will fully discharge and will support the amplifiers specified rating.  However, when they grow old, and get dry. The power supply simply can't deliver the power and the amplifier power is reduced.  This is only a guess though.  I have no experimental basis for this.

So this leads me to believe that the same benefits could be gained from an amp as little as perhaps 5 watts per speaker channel at the volumes I listen

This is likely.  That little Pilot 240 El84 push pull amp at about 12wpc really amazed me.  There are obviously other issues such as dampening and feedback for the amplifier.  The pilot 240 and 232 are pretty cheap on ebay - about $200.  This might seem expensive for such an old low powered amp, until the tubes glow in your own system.  I am not a "tube guy".  I am a quality guy.  However, relatively cheap amplifiers tubes generally compete very well - IMO.

Thanks for taking the time to perform the measurements on your system.  This is very enligtening for most folks.  I convey these issues because many very sub-par commercial grade amplifiers have lured folks into thinking more power is needed.  Such isn't the case.  

Also, many folks claim that amplifier headroom is a good thing.  I disagree.  Dave Ellis maintains that too much amplifier is simply too much amplifier.  Wise use of $ resources is extremely valid in this realm.  I'd much rather have a quality amplifier that does precisely what I need, than lesser quality amplifier with a bunch of headroom.

On the soapbox...

[konut]

Interesting discussion, which probably deserves a new thread. Prior to the introduction of MOSFET and JFET based solid state amps, it was pretty typical to see distortion curves that started out at a certain level, say .5% distortion, and then gradually diminish to .1%, as the power output approached rated output, then rise very dramatically after rated output. The MOSFET and JFET designs differed as they started out with low distortion right from the first watt. I suspect that your old Kenwood receiver, David, is not a MOSFET or JFET design. The F10's being a digital amp, I would suspect, and please can someone more knowlegable than myself comment on this, that it's more similar to a current drive design, similar to Nelson Pass's F1, than a voltage drive is as typical almost all solid state amps. That would certainly explain it's better behavior with difficult impedance loads and timbley's satisfaction with the clarity. This would also explain why so many are finding satisfaction with these digital amps on full range high efficiency designs. On Nelson Pass's F1 website, he goes into great detail about how current drive is more suitable for crossoverless designs. With active crossovers, in effect, the amp is dealing with a crossoverless load, as the amp is being fed an already bandwith limited signal with no passive electronics, aside from the driver itself, on the output. Just a guess.

The fact that timbley is bypassing any corrective frequency shaping provided by the Klipsh's passive crossover would suggest that, yes, line livel equalization is needed to get the RF-7s to produce anywhere near flat response.

[doug s.]

Hello,

I'd like to quickly comment on my experience with bi-amping my monitors.
First, I'll admit I own a pair of Dave's 1801's and you might consider the following biased.

I bi-amped my 1801s using an Odyssey Stratos for the woofers, Jolida 801A for the tweeters and Marchand XM44 handling the XO duties.  I did this only because I had an opportunity, and was curious what all the fuss was about.

In brief, the results were very under-whelming. The speakers always sounded unnatural and I could never  ...

i am not sure how much useful info can be garnered from this.  did you disconnect the passive x-over prior to going active?  were you prewiously passively bi-amping w/these same amps?  it's not always easy (or ideal) to use s/s amplification *and* tubed amplification when the x-over point is much higher than ~300hz...  active *or* passive...

thanks...

At the Iowa DIY 2004 gathering I was able to listen to Jim Salk's Veracity 3 (passive) and John K's NAO (active). Both speakers sound extremely good, but the sound quality was equal IMO.

again, i am not sure what useful info can be inferred here, re: active vs passive.  it's comparing apples to oranges.  now, if john k were to attempt a fully passive wersion of his speaker to compare to his (partially) active wersion, *that* might be useful.  same goes for the veracity 3  - we would need an all out assault of that speaker w/active crossovers, to compare to the present iteration.  (and, perhaps an all-out assault of the l/r orion in a passive wersion may also be useful to compare to the active iteration.)  

regards,

doug s.