I'm in the process of trying to determine if I should purchase a pair of Genesis APM-1 speakers that have become available in my area. However, in my many years of listening and experimenting with audio equipment I have never used dipole speakers and need some advice.
My current system consists of an older Shanling solid state CD player, California Audio Labs DAC, Rogue Audio 100W Sphinx integrated hybrid stereo amp and Martin Logan Odyssey speakers. My main concern is that, because I listen primarily to solo guitar and light jazz, the expanded soundstage that I've read that dipoles are known for, might not be a good match.
Mrmb, yes, I do have some success to report. I mounted the acoustical foam on the back of the frame about 10" behind the panel which keeps it mostly out of sight. Based on my way of thinking, because of the concave design of the rear face of the tranducer, placing the damper closer to the source may be more effective for this design.
Anyway, listening to solo guitar seems noticeably improved. The most notable of these improvements seems to be an enhanced center stage effect. The overall presentation seems less complicated and cleaner. I really don't know how to describe what I'm talking about but, although the differences are subtle, I can definitly say that I like it better.
The biggest enhancement to my listening enjoyment, though, is my having been fitted with a good pair of hearing aids. I recommend this approach, btw, to anyone having difficulty finding problems with their equipment. It might be your ears. I know this because I spent over a year replacing components, interconnects and speakers to correct what I perceived as deficiencies in my system.
Thanks for your advice. What I described as egg crate is actually of a pyramidal design so is probably a little more efficient because the angle of attack of the sound waves is shallower.
As far as SPL value is concerned, what I consider loud depends on the frequencies in question, but, in general, it would be somewhere in the vicinity of the mid 70's.
Mrmb, thanks. The foam that I got, and I should have been more clear, is not the cream colored rubbery stuff that one puts on mattresses. It is acoustical foam (polyurethane or polypropylene?) sold specifically to reduce hard surface reflections. By most standards, though, especially materials made for commercial anachoic applications, it was quite cheap. A 4'x8' sheet was less than $80 of which I only used about half.
Maybe now that I know it works I may look into trying some higher quality purpose designed material.
If the egg crate foam helps, you may consider something with more of a broadband acoustic effect.
Several years ago, I built 2 DIY acoustic panels via Jon Risch's design perameters on AudioAsylum. My final floor standing-size products were 6'H x3'W x18"D. I'm still using them. But while researching these, folks mentioned that egg crate foam -- the type used as bed toppers -- although it looks like the foam used in studio's, it really wasn't, and didn't have the same acoustic properties. However, it certainly should give you the opportunity to learn (rather inexpensively), whether you're on the right sonic/acoustic track or not.
FWIW, Soundlab sells an item called the "S.A.L.L.I.E".
S.A.L.L.I.E.'s are mainly for those who can't pull their stats very far out into the room. They're rather expensive, but perhaps one could produce a similar DIY device.
I've also heard it mentioned that artifical floor standing plants behind dipoles also acoustically helps.
Mrmb, I decided not to try the felt; the egg crate design foam seemed to more closely resemble the material used in anachoic chambers that I've seen. Also, felt actually seems like a fairly hard material, now that I've looked at it, and it may be somewhat reflective of sound energy itself.
Anyway, the design I'm using will be an attachment to the Odyssey cross brace holding the damping material approximately one foot behind the tranducer. I could easily be wrong in assuming this but, because of the curved design of Martin Logan panels, damping material closer to the speaker may work better.
Whether the felt panel works or not, it would be great if you let everyone know via this thread.
Additionally, some acoustic panel manufacturers make stand mounted panels. These positioned behind your M/L's may be less visible & hence, less likely to be an aesthetic issue.
That's good to know. You can also try doubling the thickness of egg style foam to see if it improves some more.
I think a higher density absorbing material will ultimately be your solution for the Odysseys if you are looking for further improvements. Several materials have been presented here.
On a separate note, what is the dB value of soft and loud volumes you are listening to? If you don't have an SPL, several apps can be downloaded for free. For me loud is 80dB or more, and the panels remain effective at minimizing the reflections. As you pointed out, the louder it gets the more effective the results.
Jcharvet, I bought some egg crate design open cell foam and cut two panels from it to match the dimensions of the transducer panels of the Odysseys. i had my wife and a grandson hold these panels about ten inches behind the speakers and started listening to solo guitar CD's.
At lower volumes I could discern no difference whether or not these dampers were in place. At higher volumes, though, there is a noticeable difference which seems better with the dampening in place. This difference seems as much related to an improved center stage as anything else. The bottom line is that this reduction of reflected energy improves listening for me, at least for this solo instrument.
Thanks. Even though we could attempt matching our room decor, because a lot of time and money went into finishing this room to our tastes, we really don't want to hang anything on that wall. I do, however want to experiment with dampening as you mentioned.
I'll try the method that I already alluded to. It sounds like you're familiar with the construction of the ML transducer frame so I'll explain how I intend pulling this off. Using a felt panel cut to the dimensions of the transducer, I'll use the topmost frame cross brace for attachment of the cloth to the back side of the panel. It will hang about 10 inches behind the panel.
If this works out for listening to solo guitar I can leave it in place with the option of easily removing it for listening that requires a more expanded soundstage. I'm going to a craft shop tomorrow and choose an appropriate material.
As an addendum to the information provided by Jcharvet, indeed heavy drapes or rugs will work. However, for my application, I purchased absorption panels from Acoustical Solutions: http://www.acousticalsolutions.com/acoustical-wall-panels.
Additionally, one can either buy purchased complete panels as I, or DIY, by buying Owens Corning 703 panels, fabric, etc. such as available here:
After I mounted apsorptive 2" thick panels in back of my Soundlab ESL's, wow, what a positive difference (huge smile)! They improved the sonics at least, if not more, than any item that I ever bought! Frequency response remained essentially the same, but focus, clarity, imaging and soundstage dramatically improved.
My experience (at least with Soundlabs) suggests that its paramount to absorb the back-wave emanating from the panel and its quite difficult to overly dampen that portion of the listening room.
Before installing acoustic panels, I allowed uncertainty with the science verses the art of acoustics, to inhibit purchasing and installing treatments. However, Roger Wests discussion via Soundlabs set-up tips page http://www.soundlab-speakers.com/#!__technology/setup-tips, and discussions with a local audio store owner whose opinions I respected, convinced me that installing absorptive material is better than not, and if that were so, I needed to do more and as Ive discovered, the end result was a resounding success and highly recommended!
In my set up, I use two 2' wide by 4' tall panel. They are oriented so that they are covering the back end of the electrostatic frame and not the subwoofer enclosure. The idea is to eliminate the dipole reflection.
You will get some effect by placing different types of fabrics or rugs behind your speakers. The best materials are those that absorb the sound and not those that reflect or diffuse them. Your best bet is to go to Lowes and buy two sheets of insulation (Roxul about 3.5" thick each) and place them behind your speakers. The plastic covering might reflect the sound, so you might have to open it. You can always return them after performing your experiment.
There are many finished acoustical panels available out there. Some of them can print pictures on the fabric cover to make it more room friendly. Mine are from Mix Master Acoustic, and I find them sonically and cost effective.
"FWIW, careful set up of well designed conventional speakers in a good room can improves on anything that dipoles can do."
Generalizations may allow one to minimize variables and more easily formulate a conclusion; however, as in life and this hobby, they rarely represent the final word, or conclusion on the subject. This generalization regarding conventional vs. dipolar speakers is no exception.
I've heard outstanding music reproduction from every type of speaker (dipolar, horns, so called conventional and otherwise), amplifier (tube, SS, SET, etc.), turntable (high/low mass, belt and direct drive etc.), DAC (SPIDF, USB, tube, etc.). Not blindly believing that any of these, or for that matter, any type of music reproducing hardware is inherently better than the any other type, is the reason why I frequent this forum.
Do I have my preferences and have I found synergy with the components I own, yes. But do I believe that my way is the right way, or that dipole speakers properly setup sound better than any box speaker, or vice versa, no; and the same applies to every other sort, or type of music reproduction devices that are available.
Broadstone: My dipolar type loudspeakers provide a spectacular center image as well as a great soundstage. As the manufacturer suggested, I have the speakers well out into the room and have installed absorptive panels in back of them to ameliorate the back wave.
However, I suggest that you keep trying different speakers and certainly types -- albeit: open baffle, boxed, panel, horns, etc.) to determine YOUR preferences. If audio retailers in your area are limited, you might consider some road trips, or attending one of the many audio shows that occur annually. While setups during show conditions are obviously not the best, a show's advantage is that it allows you to hear lots of different speaker types which may allow you to more easily hone into the sound that you prefer, or are seeking. It's not really about what my preferences, nor any others on this forum. It's all about your preferences. For the most part, there is no right, nor wrong way in this hobby, just different ways to enhance our musical enjoyment.
Jcharvet, thanks for this advice. Even though I've used dipoles for so many years I've never tried this, primarily because my listening room is my living room and we were concerned with how it would look. In the past several years, though, I've begun listening to a lot of solo guitar and maybe it's time to revisit the thought of limiting the phase effects of the ML's.
In regard to this, I'd like to know how important it is to have the panels located on the wall. It would be relatively easy to experiment with this idea but do you think it possible to accomplish the same effect by hanging something like a panel of felt behind and attached to the frame of the transducer panel?
Newbee, thanks again for your input. Yes, the Odysseys are somewhat of a setup challenge, an issue that I've dealt with for over 30 yrs. During that time I've used Acoustat, Martin Logan and Magnepan. Maybe it's because of the curvilinear design of the ML's but I found these to be the biggest challenge of the panel speakers. Also, I find that the setup requirements, especially as regards toe in, seem to be different between orchestral vs single guitar music. I know, I know; this may be a mental issue but it's how I perceive it to be.
As I mentioned earlier, I recently added a pair of Jamo Concert Eights (great speakers, btw) which I bought used, just for listening to solo guitar. They present excellent detail with surprisingly tight and very ample bass. For a larger stage such as for symphonic music I find the the Odysseys are completely adequate. For small jazz groups it is a toss up between the two sets of speakers.
This is the type of compromise that probably most audiophiles would find an affront to their sensibilities but, again, it works for me. Don't get me wrong, though, if I could afford the expense that I assume would be attendant with high end conventional speakers I would welcome the idea of a single pair for all of my listening genres.
Broadstone, FWIW re stereo v mono, one of the differences that you hear when you are listening in mono is that in mono you are not getting reproduction of the out of phase information in the recording which will appear in stereo playback, and is one of the things that enlarges the sense of space. Add to that enlargement, the back wave from dipoles and you can get an overly expanded stage (which some folks like, some not so much). When you go to conventional box speaker, properly set up, you can get a very accurate reproduction of the performance and venue. If accuracy is what you want! And therein lays most of the difference in preferences for speaker design.
FWIW, careful set up of well designed conventional speakers in a good room can improves on anything that dipoles can do. IMHO, dipoles survive mostly because they do enhance the soundstage effects many folks are unable to achieve using conventional speakers. It is just easier to get, so long as you are not too critical. If you are a critical listener, you may find that proper set up of dipoles can be a real bear.
Dweller, I'm not that well versed on audiophile terminology so I can only attempt to describe my issues using terms that I hope will make my point. I'm not trying to "remove" soundstage; I'm simply trying not to add apparent room filling sound where it should not be. I only occasionally listen to orchestral music and appreciate the fullness that I get from the Odysseys but when I'm listening to one person playing one guitar, I want it to sound that way. It was for this reason that I originally had questions regarding a way to employ monaural listening using a stereo system.
Elizabeth kindly responded to that post with advice regarding my speaker setup. Thanks, that was one of my original concerns and I believe that my speaker setup is correct. BTW, Elizabeth, based on hearing issues that I had described, I was fitted with hearing aids. The jury is still out on that one. Although my hearing is improved for general social communication, I'm not yet convinced that listening to music is enhanced except that I'm able to discern detail at lower volumes.
I have a pair of ML Summits and hang thick, picture-frame style absorption panels on the wall behind it to eliminate/minimize the dipole effect. It is very effective, and you will get what you are looking for. You can "turn on/off" this effect anytime by simply placing/removing the panels.
Broadstone: The character of the recording is determined by the Artist/Label/Engineer priorities. An example is the Glenn Gould "Re-Performance" of the Goldberg Variations (DSD recorded by Zenph Studios on Sony Classical label). I was hoping for a Grand Hall acoustic but got a dry intimate presentation instead. In other words, if the soundstage is in the recording, your speakers won't remove it.
Solo guitar and light jazz,get yourself a pair of Harbeth P3 ESR'S. No speaker I have owned reproduces a guitar like them. And placement on these are a breeze!
Yes, electrostats are also dipoles but I'm having difficulty with definitions that I've recently read in regard to dipoles in general. Descriptions are not all exactly the same but the things that seem consistent across the board are that the designs require speakers to be in separate enclosures facing both front and back in an out of phase configuration or that the speakers are mounted on what amounts to little more than boards. The term "enclosure" is also confusing in regard to the open dipole configuration.
My question regarding dipoles being used for solo instruments goes to another thread that I initiated and Elizabeth kindly responded to. I was soliciting advice regarding monaural presentation of solo guitar music that may be a more pinpointed as if the artist was sitting across the room. From what I read about dipoles, which would include my Odysseys, is that they create a wide stage which seems the opposite of what I'm trying to achieve.
I recently have my Odysseys configured with a permanent A/B selector device with a pair of Jamo Concert Eight bookshelf speakers. These Jamo's present a realistic/accurate reproduction of guitar and light jazz but are lacking something when listening to classical symphonic music or movies (in stereo) so I need to find a single speaker pair that satisfies both of these two extremes.
The bottom line is that I remain confused. I'm pretty sure, though, that, even though the Genesis is a really beautiful speaker, I should start looking for a decent conventional speaker instead of continuing with the dipoles. As a matter of fact, from what I'm reading, dipoles seem to be the speaker of choice for surround sound, something that I no longer listen to.
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