Do high-efficiency speakers really have better 'dynamics'?

[Duke]

Kates’ paper used 2D modeling, which omitted vertical modes with monopoles, and that made them look lumpier than they really are (Kates assumed dipole bass is line-source-like and has no vertical modes), and the paper attracted criticism for that.

My in-room measurements of large line-source-approximating dipole speakers versus monopole speakers agreed with Kates, but were made many years ago with a borrowed real-time analyzer and not recorded so I cannot present them here. Earl Geddes disagreed with Kates, and I think that was over the two-dimensional modelling Kates used (which I had forgotten about). Perhaps behavior approximating a line source plays a much bigger role than I had appreciated in the (ime) superior in-room bass smoothness of a large dipole versus a monopole, in which case my example of "two monopole subs back-to-back" was a poor illustration of a large dipole panel speaker's behavior in the bass region. Thanks for pointing that out.

Also, why jump to 4 monopole subs? Just because 4 monopole subs in bad locations and phase and positioning will look like a dipole bass pair? Toole showed how much smoother the bass can be with 2 well-placed subs than with one

I agree with Toole that two well-placed subs will have smoother bass than one.

Four is not a magic number, but four well-placed subs are better than two for the same reason that two well-placed subs are better than one. Geddes articulates the underlying principle:

"The use of multiple source locations in the modal region will globally yield a response curve that is closer to the natural power response of the sources and the room. Said another way, if we use multiple source locations the frequency response at any given location in the room will become closer to the true power response (read smoother) the more sources that are used. Basically if I have one source which has a variance, V, of the frequency response (the variation of the response from the average or smooth response) of say 6 dBs, by adding a second source we will reduce this variance by half to 3 dB. Adding a third source reduces this to 2 dB, etc. Basically the variance goes as V/N where N is the number of “independent” sources. A key requirement here is “independent”. If the added sources are close to the first source then they are not independent. And two sources in opposite corners or symmetrical locations are not as independent as two sources placed in non‐symmetrical locations. It is impossible to have two sources that are completely independent at LFs in a small room, so the effect is never as good as the formula suggests." (Emphasis Duke's)

If by any chance you might be attending the Axpona show in a few weeks, I hope you will stop by Room 709. There will be a distributed multisub system in that room, and whether or not we agree on its merits I'd enjoy meeting you.

 

[Duke]

Remember that bass EQ should do very little boosting, instead, mainly cuttiing the heads off of resonant peaks. Which doesn’t require more power.

I was talking about what it would take to achieve comparable bass extension and SPL from comparable vented and sealed boxes, sorry that wasn't clear.

A vented box is theoretically 6 dB more efficient than a sealed box at the port tuning frequency (in practice it's slightly less). This boost in efficiency tapers off gradually above the tuning frequency and nose-dives below the tuning frequency. So assuming two comparable-sized, competently-designed vented and sealed subs achieve the same in-room -3 dB frequency at the same SPL, the sealed box will require greater amplifier power and greater woofer power handling, as well as EQ (in most cases), to get there.

There are tradeoffs which favor sealed boxes as well, so it's a juggling of tradeoffs and/or a minimizing of shortcomings.

 

[40th Anniversary]

So did I Matt. After reading about high sensitivity speakers with low wattage valve amps I wanted to hear some so I went to listen to the Devore O/96's just yesterday. I tried listening to the same test tracks on my system just before I left (Revel F228Be/ARC VT100 MKll/Conrad Johnson ACT2/VPI Classic Series 3/RME ADI2 DAC fs) and left the session with the same feeling about the Devores as Matt. (They were paired with a Jadis 60wpc tube integrated.) There was a richness, a weight, to the sound as well as an ability to present every nuance, especially on vocals. I started by playing two tracks by Gregory Porter, God Bless this Child, (an acapella version from Be Good) and then Liquid Spirit (Claptone Remix), and while polar opposites the Devores presented each convincingly, seeming to display each tracks strengths equally well. (By the way if the remix of Liquid Spirit doesn't get you moving you're dead!)

I'm not at your guys level technically (I'm trying to learn) and don't have much experience with horns at all, but I really liked what I heard. I especially appreciated their sound at lower volumes. By the time I left I liked them enough that I'm already starting to rationalize how I might swing getting a pair.

Never heard the O96, but would love to. It looks so awesome as well! That woofer is simply...magical!

I think the impact of 1. a bigger woofer and 2. less drivers have left impressions on me over the years in terms of dynamic presentations.

A big of a digression: I'm currently building & experimenting with the SEAS 10 inch woofer (A26RE4) in a Dynaco A35 clone project: it has not worked out as the cabinet is over damped. I've added an external vent and it has helped. I am now going to open up the enclosure inside and see if that improves the overall bass response (closer to the A26 project, but in a cabinet the size of the original A35).
I find the original A35 somewhat dynamic.

Had Tannoy Chatsworth (pepper pot tweeter) that I found quite dynamic on some material; and an older pair of Cerwin Vega PD-15s with a horn tweeter.
I've recently acquired a pair of Triangle Comète 40th anniversary with a Magnesium Horn Tweeter which has made me discover the love of good horns in a fairly compact speaker for smaller rooms.
I'm gonna planning to audition a pair of Amphion one12 or one15 in the new year to listen to their waveguide design.

MY CURRENT QUEST: a pair of smaller desktop speakers that offer that magical dynamic presentation! Does such a speaker exists?

Love this site and all the opinions, references and knowledge that is shared. Simply amazing! Thank you.

 

[mhardy6647]

somebody say something about magical woofers?

 

[Doodski]

somebody say something about magical woofers?

Also amazing is that those AL woofers have stood the test of time. The paper and the fiber surround suspensions have held up very well from what I have seen.

 

[mhardy6647]

If not abused.
Sometimes the surrounds do get very tired, though.

 

[Doodski]

If not abused.
Sometimes the surrounds do get very tired, though.

Compared to the foams used today AL nail'd it.

 

[mhardy6647]

well, yeah -- but foam is easy and inexpensive enough to replace.

 

[Doodski]

well, yeah -- but foam is easy and inexpensive enough to replace.

I would take a woofer that lasts 50+ years than a woof that with some sun falls apart in 3 to 5 years.

 

[Senior NEET Engineer]

Higher sensitivity speakers sometimes have rolled off bass and elevated treble. If you applied this kind of EQ to a song, it would increase the DR score.