How to shop for speakers?

OK, I've got the upgrade bug. My problem is how to evaluate speaker auditions given the limited local choices and the inevitable differences in amplification, room, etc. I have a local dealer who will let me do home audition, but he does not carry 4 of the 5 brands I am interested in after attending RMAF. He is even getting the mfgr to send a pair for my audition. My problem is how do I judge the various speakers given the variability in listening environments and the time lapses between listening. Buying used for home auditioning and selling what I do not like does not seem practical to me given the price range I am looking at - not much available used in this range and too much potential for significant loss with each transaction. Besides what if I sell one I later decide was the best.

My short list after attending RMAF:

B&W 800d or 802d - not so impressed after dealer demo
Dynaudio Confidence C4 - waiting for dealer to get one for demo
Wilson Sasha or Sophia3 - was blown away by the soundstage of the Sophias at RMAF
I would like to audition Revel Salons or Studios or Sonus Faber Elipsa but local dealers are installers and do not have demo capability

My favorite at RMAF was JM Labs Maestro Utopia but they are out of my price range new.

Amplification is McIntosh MC501 ( this makes me a non-audiophile since I read in another thread that audiophiles do not use Mac equipment - I'm fine with that since I really like the music more than the equipment). But, I would like to hook up a MC275 during the hot summer months to listen at low to moderate levels.o

Not sure if this is a gripe or a request for advice, but I will appreciate any guidance that is offered other than the usual " you listen and decide" I already appreciate that.
I would just like to point your attention to the fact that you might be unable to get the speakers you want. At least new. Do you consider buying used or waiting for a demo pair to show up?
I personally would avoid spending a lot of money and still not getting what I really like. It doesn't have to be the very best but should be good enough.
I agree with Inna... you should seriously consider used speakers. Then if you are not satisfied or want to try another flavor you can move up, lateral or down with little financial loss.

BTW, as a previous Dynaudio C4 & Mac MC275 owner, I can tell you that the MC275 will not have enough muscle to drive the C4's, but your Mac 501's should work nicely. Keep in mind the C4's need room to breath (at least 350SQF), need to be pulled away from all surrounding walls by at least 48" and are not very good @ low to mid volume levels.... they need to be cranked up to sound their best.
I would buy these speakers:
Their current cost would be around $30,000 at least judging from the recent inflation of audio equipment prices. They use the same tweeter as Wilson uses[ although Wilson claims to modify them]. I had a pair of the Mini Utopia from the same period with the same tweeters and they were excellent. I sold them for exactly what I paid for them. I have not bought a speaker on personal audition since the early 60s; when I have heard some prior to purchase I have bought them DESPITE the audition, not because of it. It is really hard to hear speakers in anything like a home environment, most stores do not have good acoustics. I would buy something like these speakers and live with them for a year or two, you may want to keep them, if you don't you will have a much better idea of the sound you are looking for. In any case you are not likely to lose money. I don't understand why the 275 would be good for the summer months, most people want a SS amp for summer because of the heat. I like the 275 better than the Mac SS for what that is worth. I have absolutely no connection with the seller above, they just look like a good deal to me. I recently purchased a pair of speakers used and unheard and am very happy with them, but I know pretty well what I am looking for. Live with a really good speaker for a couple of years and you will too.
Altbrewer...there is no easy answer to your direct question. My suggestion would be to try to audition the speakers whenever business or personal travel takes you to a major metropolitan area that has 3 or 4 high end audio stores that are likely to carry the speakers above. Make arrangements in advance to book some time in their listening rooms with equipment that is similar to yours to the extent possible. There is no way to adjust for different room acoustics and ancillary equipment other than to note where you thought the performance was being impacted by sub-optimal set-up. At the end of the day, there is always some risk when you make a purchase decision if you don't get a chance to audition that gear in your system (which is rarely possible unless you live in a big city and have a good relationship with the local high end stores). The advice above about buying used is one thing to consider as that will limit financial loss if you need to turn around and resell one of these speakers. I would also make sure you have done your research and upfront thinking on matching amplifiers with the speakers selected. The MC501s should be able to drive all the speakers on your list. The MC275s however are likely to have a hard time with almost all the speakers listed above except for the Sophia 3s maybe. Good luck.
I have to agree there is no easy answer. The absolute best way is in-home demos. That way you will know what it sounds like in your space with your setup. FWIW - my favorite speaker is the C4. I prefer them over the consequence ue (well except for a party maybe). But have yet the hear the Evidence series.

That's my opinion and good luck
IMO, you don't need to listen too long to know the speaker is really good. If you need to listen too long, the speaker is probably just so-so, so I would avoid it. I know dealers can and do give crappy demos, but the good one try to make things sound as good as they can. Things like room tunes etc can make a great speaker better, but can't really correct for a less than steller speaker.

Real life example. I walked into a hi-fi dealer and heard SoundLab speakers for the first time (I had never known about the brand before this). I walked out 15 minutes later the owner of a used pair they had for sale. I had them hauled over to my house the next day and never had any regreats.
I almost bought a whole Meridian system this way too, but I could not quit swing the $$$$.
Before this, I had bought the Mirage M3si speakers (still one of my favorite speakers) from a store. I heard them one day and went back the next day to put in an order for a new pair. Never had any regrets. This is one set of speakers I really got my money worth from and still have them.

Hey, maybe that is a great idea- sleep on it . Go listen and if you still remember something good a few days later, then maybe you found it.
I would only throw into the mix, clearly understand your own listening room before listening to any speakers. I know my room, I know how I have to lay out my tunes for best results. I know that very small, very low sensitivity speakers won't do well in my room. I know that I have very good room boundries to produce bass and don't have too many nasty room nodes to deal with. Figure out what hard and soft surfaces do to the mid and high frequencies in your room. You can then have your information as a reference as you compare your listening environment where ever you are and have a better chance to get the results that you are after at home. Like some of the others, I would strongly recommend a good used pair. If they aren't what you like, easier to move without getting bitten too hard. Good Luck, Tim
Use your own CD's to evaluate and compare each finalist with the same tracks. Use a variety of music. Do not be surprised if some things sound better on one speaker but other things sound worse. Try to go with a speaker that presents the sound from your catalog correctly balanced rather than what sounds overly pleasant - it is hard to resist a speaker with plenty of bass (all your selections have this in spades) but try to look for balance as it will be more rewarding in the long run.

The Revels are the more balanced speaker in everything you have mentioned so far but they might not impress you in a ten minute demo as much as something with heavier bass. However, they might be more rewarding over the long haul.

With a bit of experience you can tell what is room and what is the speaker behavior. A good speaker will sound the same at any volume but at high levels the room will come to life and get energized. Excessive volumes in a space that is too small will sound harsh and claustrophobic. Speakers nearly always sound better given more space (within reason of course)
Stanwal, I proofread my posts but missed the error in this one. Of course, I meant to say I used the MC275 in winter, not summer. Also, I would not expect the MC275 to drive any of these speakers to loud volumes, but only for quiet, mellow listening.

To all other responders, thanks. I do believe that home audition would be the best way to judge a speaker, but it doesn't seem practical in this price range. I am not opposed to buying used, but I am not sure that I would feel I got good value if the trial and error process went on too long with, say, a 10% loss each time, for speakers costing this much.

I feel pretty good about looking at the listening room at the dealer and comparing it with mine to get an idea of how the speaker might work at home, but not so much with figuring the impact of the different electronics and cables.

I spent my entire career using objective data to formulate my work product, so I guess what I am looking for is a systematic method that will allow me to compare speakers in different locations at different times. Using a single set of music tracks is a good idea, and I am in the process of making notes about what I listen for with each cut.
I'm reluctant to recommend a speaker to someone I don't know, but I kind of like Stanwal's recommendation if the JM Lab house sound appeals to you.
6550C, your approach is interesting but not, I think, without flaws. You really liked three very different pairs of speakers - SoundLab, Meridian and Mirage. They all must've had something in common in the way they presented music. Do you know what that was?
Altbrewer, I guess you are prepared to replace your amplifiers and cables to better match the speakers you very much like, just perhaps not right away. Because if not you will make your task even more difficult. Say, Revel and Sonus Faber are quite different. A number of years ago I heard both, near top of the line models, with different amplification and definitely preferred Revel. If I remember correctly, Revels were driven by Krell monoblocks and Sonus Faber by McIntosh. Revels had clarity, dynamics and balance. Sonus were too mellow and romantic and slow.
Maybe......spend the weekend in the nearest large city with dealers for what you want to audition. Have everything pre-arranged so stuff is waiting when you show up and you can get down to some serious business. Having Mac amps is almost a must.....and a PIA to bring with you, especially if you must fly.

Some speakers may eliminate themselves from the running and you can than concentrate on the rest.

I know of no way to decide other than by ear. I could say.....'Get Magnepan MG20.1s and be done with it.' Never saw your room and have no idea if you like panels. Your listed choices strike me as different, or maybe without a 'theme'.

Post back when you make a purchase....with a 'mini' review.....
Bring your own music with you too,good variety,if somebody didn't already mention it.
Simply request from your Audiogon siblings if they would allow you to listen to the speakers and equipment that you would be interested in and they will open their doors to you. I have the Revel Ultima Salon 2's and you can hear them if you are willing to come to the Boston area.
6550c has a point. I expereinced the same thing with Spica TC50s years ago. I olistened to everything I could for miles around, and wasn't happy with any of it. I discovered a new store that had opened, heard the Spicas and knew they were the ones. I still have them 24 years later.
"When it's right, you'll know it"
Of the speakers you've mentioned I think the Sophia 3 is the only one that can do what you want. I think the 2275 could drive them, check first, and they would work very well with the 501. I owned the Sophia 1 and I thought it played well at low volumes. I've heard the Sophia 3 it's a fantastic speaker, the bass is more powerful than the 1's so I'm sure it will play at low levels better.
The final test for the dealer to let you take them home, whatever the choice. Only in your listening room can a 'final' choice be made.
when you are looking at expensive speakers you don,t want buyers remorse or you will be less than happy. this is a very problematic question and my thinking is i just enjoy the music on what i,m using now and have the fun of planning my next assault on blowing money. most audiophiles don,t stick with one speaker forever but i have read that magnepan owners are some of the most satisfied with their decisions,,,but so are bose owners. good luck and enjoy the process because a decision made under stress can be regretted. thanks john

Had a pair of M5's. Loved everything about them. Really responded to different amplification. Just need alot of room to really breathe well. Thats why I sold 'em. Just couldn't do them justice. Miss 'em tho'.


You have a difficult dilema. Alot of good advice here. I believe used is a good option. Read about systems and their characteristics. Determine what is important to you. If you can't hear an exact model often models in the same line have similar attributes. That may help.

Hopefully things you do hear can be as similar to your set-up at home i.e. source, amps etc. Impossible most of the time. I know you don't want to hear it but until you get it home with your own stuff you're never going to know what its really like.

At least if you find a line you like, are impressed by models within that line perhaps a used purchase won't be so daunting. You may find you scored! I bought a pair of monitors like that. Years ago heard larger speakers in the line-up. When I needed to downsize and saw a pair of monitors from the manufacturer on Agon I remembered what I liked the most of those speakers. So I researched them a little more and pulled the trigger. I am not saying I remembered all the subtle nuances of the speaker but I did remember what impressed me most. And that plus the characteristics of the monitors as point sources helped me arrive at my decision.

My 2 cents. I know you got a tough choice ahead of you and wish you the best.
I like Aaronmadlers idea of using Audiogon to find users nearby to audition your choices. Some speaker makers even formalise this, with a list of users prepared to Dem, particularly the smaller manufacturers. tyler comes to mind. Many in the hobby are thrilled to meet other enthusiasts. HiFi can be a solitary business, in my case, the family think it all a bit weird, but tolerate my foibles.
I personally dislike auditions in a dealers. You can almost hear the meter running... time is money, time is money. You always feel the pressure to place an order, except in the best.
I would add Vandersteen five As to your list
They can be tuned to your room will then disappear as many other speakers hope to but only in ideal rooms. One of our Clients has them sounding great with Mc 501s and Kimber Kable
Best Johnnyr
I would second the comment above on knowing your room; what size is your room and what limitations (if any) do you have on speaker placement? All of those speakers you mentioned are very good; very good in the right room...

Second, I also agree with trying used; you can get some really great deals on used speakers right here on Audiogon. Narrow down your choices to a couple of candidates then watch for the best deal on nice used pair.
While I appreciate the specific speaker suggestions that have been posted - they have opened my eyes (ears?) to others I should consider - I am really looking for a methodology to evaluate speakers when they are auditioned at different times in different settings and with different electronics. I agree that the best evaluation is in my own listening room, and that is how I picked my current speakers.

Regarding the comment that there is no common thread in the speakers I listed - there is, but it is not an obvious audiological one. They are speakers I have heard briefly and liked, and have been well spoken of. I do not feel I heard them long enough or with music of my choosing, so I would want to audition them in greater depth before making a buying decision.

I would buy used if I wanted to use the hit or miss buy and sell method, but if I take up the dealers time and resources, I am more inclined to buy from the dealer. Still, if the dealer of the model I decide upon does not give good service, then I would hope to find what I want used.

Finally, my room is 19x17 feet with the speakers on the shorter wall. Currently they are almost 4 feet from the front wall and about 3 feet from the side, positioned by the Iron Chef Speaker Setup Protocol. I'm not sure my wife will tolerate this much longer as they are almost directly in front of the door from the garage and really need to be closer to the wall to satisfy her.
Methodology????? A great thread on its own... My first impressions are based on tonal balance, is the bass tight, fast, full, boomy??? Is the mid range through the top end articulate, detailed and smooth? I've built alot of speakers in my time, I'm a stickler for drivers matching sensitivity and am annoyed by mis matches. Next, I listen for sound stage, I have recordings that I am very aware of. Is the stage as deep, wide, tall as I am used to, how is instrument placement on stage? Are these speakers dynamic? Yes/No, what amplification are they using and how does that affect the dynamics, warmth or lack of, dryness or sweetness on top or total accuracy. You get the idea, this can go on and on front end? cd? phono section, cables, yadda yadda yadda. Good luck, Tim
The issue here is matching- you might want to look at this:

IOW, If you know that you are wanting to use tubes (Mac275), you have to look at speakers that are friendly to tubes. Since tube power tends to be more expensive, I would reject speakers that have low efficiencies (less than 90 db) unless you are in a small room.

Its helpful to look at the designer's intention- does he use tubes or transistors? In many ways, that is the easiest guide to start with. Wilsons, FWIW, are tube-friendly. B&Ws generally are not.
Atmasphere,you are saying,get at least 90 db at 8 ohm speakers.If you get 4 ohm speakers,wouldn't 93 db at 4 ohms,for efficiency ratings,be a more comparable match? Or,would it be better just to shop for 8 ohm speakers to play it safe? There is a roughly 3 db volume drop(going by ear),using the 4 ohm tap instead of the 8 ohm tap of a transformer coupled amp.
Yes, good point.I don't know about the figure given by the prior post,but nobody ever seems to mention this for a tube amp.Its common to see the double the wattage for a solid state amp.I tell my friends to try to shop for 8 ohm speakers for use with a tube amp,but tell them if they find a stable 4 ohm, expect some volume drop,so shop for a little more efficient speaker,going the 4 ohm route.
Speaker typically lean toward having a inductive load or capacitive load, these are normally called phase angles, they are measured in degrees. Phasing that tends toward the plus side(inductive) are tube friendly, speakers that lean toward the negative side (capacitive) are not. This is the more important factor, most tube amps will handle a 4 ohm load just fine with an inductive load. And many will handle an 8 ohm load that leads capacitive ok, but hard capacitive spikes are hard on tubes,even on an 8 ohm load and not tolerated on a 4 ohm load. Many impedance charts also include phasing on those charts. On one side of the chart you will see numbers that indicate impedance 2-4-8-12-16 etc. The other side will have a 0, then degrees going
up (inductive) and degrees going down (capacitive). If using tubes, it is almost imperative to get phasing charts on a speaker. I hope this helps, Tim
Sensitivity won't matter, if you have inductive speakers and enough power to get to the listening levels that you require. I looked up the Mac MC275, it is 75 watts, you should be fine with a minimum of 86db sensitivity. That will give you 101db output @ 32 watts. Not rock concert levels, but certainly live Jazz venue volume levels.
HiFiTime & HiFiHvn, most tube amps (that have output transformers) are designed to provide approximately the same maximum amount of power when a 4 ohm speaker is connected to the 4 ohm tap, as when an 8 ohm speaker is connected to the 8 ohm tap. There are several things to watch out for, though:

1)If an 8 ohm speaker is connected to the 4 ohm tap, which is sometimes done to achieve tighter bass or other effects on sound quality, then there would be a 3db volume drop (compared to the 8 ohm speaker being connected to the 8 ohm tap).

2)If the speaker sensitivity is rated with respect to 2.83 volts, rather than with respect to 1 watt (2.83 volts corresponds to 1 watt into 8 ohms), and if the speaker's nominal impedance is 4 ohms, then a 90db/2.83V/1m sensitivity would be only 87db/1W/1m.

3)Fluctuations in the speaker's impedance vs. frequency curve will assume different significance for a 4 ohm speaker connected to the 4 ohm tap than for an 8 ohm speaker connected to the 8 ohm tap, if the fluctuations are not in the same proportion. For example, if the impedance of a nominally 4 ohm speaker varies from 2 ohms to 8 ohms over the frequency range, a greater impact on frequency response would result (with a tube amp) than in the case of an 8 ohm speaker whose actual impedance had the same tolerance (-2/+4 ohms, meaning impedance varying between 6 ohms and 12 ohms).

Along the lines of Ralph's comment the matchup of the speaker's variations of impedance as a function of frequency, and the amplifier's output impedance, should be consistent with the designer's intention.

Also, I second Tim's comments about the importance of the phase angle of the impedance, and its variations with frequency. A low impedance magnitude coupled with a highly capacitive phase angle is a worst case load.

-- Al
Thanks guys.I guess I'll still keep using the 3 db for reference.Sometimes the 4ohm tap does sound better with some 8 ohm nominal rated speakers. That was just a guess.I had a couple of different Conrad Johnson amps,and from what I remember,they wired them all for 4 ohms out of their factory.They told me that they sound the best this way.I see an amp for sale now that has a 6 ohm,and 16 ohm output.Might be a compromise between the two.
Thanks Almarg and Timlub.Some odd things do happen sometimes.In the 80s I believe,a dealer friend tried two pairs of Rogers 15 ohm speakers on a tube amp,and it resulted in a volume drop that was enough to stop him from ordering a second pair for his home.This was on the 8 ohm tape.Being a tech,he was somewhat disappointed.He didn't bother going any further. It seems like we always are learning.I think there are some Magneplanar speakers that are a decent 4 ohm load.It would be nice to have Stereophile,or others do tests on a lot more speakers.That sure would help.To many speakers are rated 8 ohms that have characteristics that should put them in the 4 ohm category in my opinion.It makes it hard for people that starting home theater systems that can only handle 8 ohm loads.
If an 8 ohm speaker is connected to the 4 ohm tap, which is sometimes done to achieve tighter bass or other effects on sound quality, then there would be a 3db volume drop (compared to the 8 ohm speaker being connected to the 8 ohm tap).
Slight correction to this statement in my earlier post. The statement should say:
If an 8 ohm speaker is connected to the 4 ohm tap, which is sometimes done to achieve tighter bass or other effects on sound quality, then there would be a volume drop of up to 3db, the exact value depending on the amplifier's output impedance (compared to the 8 ohm speaker being connected to the 8 ohm tap).
Best regards,
-- Al
Al makes good points; all I want to do here is emphasize something that he mentions about speaker sensitivity:

Sensitivity and efficiency are different measurements! Sensitivity is 2.83 volts at 1 meter, efficiency is 1 watt at 1 meter. Now if you have an 8 ohm speaker, then they are the same. But if you have a 4 ohm speaker, watch what happens: 2.83 volts into 4 ohms is **2** watts. So if you have a 90 db sensitivity speaker that is 4 ohms, its efficiency is 3 db less, 87 db.

Conversely, if you have a 16 ohm speaker that is 90 db sensitivity, its efficiency is 93 db.

Tubes do not double power as you cut the impedance in half, and many transistor amps do. So if you are using tubes, you really have to pay attention to the significance of these figures else they will shoot you in the foot rather quickly!

Its my opinion that the sensitivity figure can be misleading, as it often creates the impression that a speaker is more efficient than it really is. Now whether we like it or not, the amount of power that the amp can make into the load is what we are talking about here- and not all transistor amps double power as the impedance is halved (and certainly no tube amp does...).

My room at home is about 17' x 22'; with 87 db the power levels for any serious dynamics gets a bit crazy- this is why I argue for efficiency if you can get it without compromising resolution and bandwidth, and quite often that is very possible. I make this point as there is a tube amp involved; if you really want to get the performance out of tubes, you owe it to yourself to use them with speakers that work easily with them. Maybe a poor analogy; but this is something like putting decent tires on a sports car that you intend to drive hard...
Hi Atmasphere, I think we are on the same page here. I have built 1 amp and modded a few, but I'm a simple minded speaker guy. I try to speak in the simplest terms possible on these forums, because it took my feeble mind a long time to get where I am, which is mediocre.
Sensitivity is a measurement of power, so 1 watt input measured @ 1 meter gives an spl or sensitivity rating... so yes 2.83 volts does measure 1 watt @ 8ohms and gives you a sensitivity rating for an 8 ohm speaker, but to measure a 4ohm speakers sensitivity, we still put in 1 watt, yes lower voltage, but 1 watt of power to get the output or sensitivity rating.
Where as efficiency ratings are measured strictly in voltage. We have found many variations when measuring a speakers efficiency at different frequencies that do not necessarily coinside directly with its sensitivity rating. Crossover components, cabinet designs and direct driver designs measure slightly different at different frequencies, thus being more efficient at a given frequency, yet overall might measure the same as a different speaker in sensitivity. Again, I believe that we are on the same page and I hope that I am only clarifying your statement. Any way you look at it, sensitivity vs efficiency is similar and can be confusing. Overall, just get enough power and if you are using tubes, try to find your speakers impedence phase angles and you will come out successful. Tim
Thanks everyone.The figures are at least good enough some of the time,but not exact since they are always changing,plus other factors.
Thanks for the clarification guys.Good minds at work here to help keep us on the right track.
Hi Tim, I think you have that backwards: sensitivity is 2.83 Volts/1 meter, efficiency is 1 watt/1 meter.
Hi Atmasphere,
I think I got it right Power = Sensitivity, Voltage = Efficiency. In the long run, it doesn't matter for what we all do and in fact the two terms are 95% interchangable. We all know what we mean when we say a speakers Sensitivity or Efficiency is 90db.
An interesting example for everyone would be what a room does to efficiency. We put set up a 90db speaker in the golden triangle in the middle of a big room, if you get a flat response, they are 90db at all frequencies. Move them back a bit and the bass is reinforced, by ??? 1 to 6 db. We still have a 90db speaker, but we just made the bass frequencies more efficient. The speaker is still a 90db sensitivity speaker, but the room just made the bass more efficient. That is the easiest example of efficiency vs sensitivity for everyone that I can think of . For Altbrewer, I have no idea how all of this will help you shop speakers, please let us know what you end up with. The best of luck, Tim
I emailed my friend that owned SpeakerCraft/Marcof Electronics, he has designed a ton of raw drivers for several different people. As an off shoot of this discussion we were discussing how we have chosen an 8 or 15 inch driver for the same design even though an 8 inch and a 15 inch woofer both have the same sensitivity and can be designed as a woofer with the same mid and tweeter, the 15 is still more efficient because how it moved more air more efficiently. Here is his reply:

Tim, while vc resistance is used as a part of motor force calculation, so is the driver cone area. You can build what you want many many ways, but to tie efficiency directly to voice coil resistance is flaky science to say the least.
Design with the highest flux density in the voice coil gap and the highest ampere turns also in the gap with the lightest moving mass with the largest cone size will win the DB/Watt/1 meter race. It doesn't mean a darn thing about how it will sound. :)
Hope this helps some! As you already know, speaker design, is a giant pile of trade offs (at best).
Tim - I think Atmasphere is right - efficinecy refers to how much power something consumes, and power is measured in watts. Sensitivity refers to how much something is affected by an input. Audio equipment, when run in its normal operating range, acts like a voltage source, so the input to a power amp or a speaker is a voltage signal. The output is then the sensitivity of that speaker to the voltage input.
Hi Honest1,
Agreed, I understand where you are coming from. I don't understand the argument. Sensitivity is rated @ 1 watt 1 meter regardless of a speakers impedance, as everyone has discussed above. It takes varying degrees of voltage to derive the power rating of 1 watt depending on the resistance of the speaker. It is the voltage that changes to measure 1 watt. The power rating of 1 watt is what we measure sensitivity. Varying degrees of voltage change the efficiency. I've had my head on backwards more than once. Either way, I have talked with Ralph and appreciate him, I have no doubt that we both understand the concept. Good Listening, Tim
Strictly speaking, neither interpretation of "efficiency" is correct. "Efficiency" would most properly be defined as acoustic power out vs. electrical power in.

However since both "efficiency" and "sensitivity" are being used in reference to acoustic PRESSURE, rather than power ("spl" = "sound pressure level"), it would seem that using "efficiency" to refer to the ratio of spl to electrical power input, rather than voltage input, would come closest to the correct usage.

And I believe that is the most widely accepted usage. Although the terms tend to be used so loosely and interchangeably that insisting on one definition or the other is probably pointless as a practical matter.

Best regards,
-- Al
Thanks Al, I had quoted my buddy Ed above, he had told me pretty much the same as you, saying no one on the forum has argued this in absolute terms and it really doesn't matter in the context that you are using it and overall would do nothing to further anyone. So as you can see, he just laid out how it is created in a conventional driver. Good Listening, Tim