Tweakers' Asylum Tweaks for systems, rooms and Do It Yourself (DIY) help. FAQ.

---

[ Follow Ups ] Thread: [ Display  All  Email ] [ Tweakers' Asylum ]

---

[ Alert Moderator ] [ Edit ] [ Delete ]

---

DIY RoomLens Cloning

203.22.142.71

Posted by Gary Jacobson on May 10, 1999 at 23:04:04

I would like to congratulate Jon Risch on his intuitions regarding the DIY "Room Lens" clone that he has described in this forum, and on his own web pages in more detail. 'Intuitions' in this instance meaning those insights gleaned from long familiarity with a particular paradigm and the applications it has to the real world, not 'inspired guess work'.

I frankly must admit to initial skepticism on the matter of these simple resonators and some claims made for their commercial cousins. I rationalised that they would, in any case, make reasonable trellising for my tomato bushes in the summer, so it would be no great loss if they did not work! In the end, the construction was so simple, and inexpensive, and the lure of a better listening experience far too great - that I had to test the concept in practice as soon as possible. The bases of the resonators were constructed from 3 layers of MDF appropriately cut out to accommodate high-density pressure pipe of 60mm outer diameter. Stuffed at the suggested intervals with polyester 'padding' as Jon has suggested (the 'intuitive' part), or 'educated guess' as he refers to it.

Jon suggests that these devices would have least effect with highly directional speakers such as electrostatic and other panel types. Another reason for me to worry (!) about their facility in relieving any room resonance problems - I happen to use stacked Quad electrostatics. I cannot comment, in a comparative sense, as I have not wheeled any box-type speakers into the room to listen. No matter - the key element here is that they DO make a difference and an appreciable difference even with highly directional speakers. This is when using the 'standard' triplet of resonators as suggested by the RoomLens folks in their set up diagrams. Various other positions were tried, and they result in 'interesting' sound staging, but I prefer to adjust for maximum focus, and depth.

Subjectively, these resonators reduce room colourations in the mids and highs. As reviewers have elsewhere commented, both male and female diction is distinctly improved. Again, with my system being especially natural in mid-range definition, I was surprised at what was revealed in both voice modulation and pronunciation, and in some cases, actually, parts of words, which were previously misinterpreted, now being easily understood. This indicates a removal of the room 'humming' in time to the tune in the critical mid-range. I can also confirm the previous observations that any given piece of music sounds marginally louder for the same gain setting than previously. I can only attribute this to the effect of there being more apparent detail. Not detail being retrieved by the system - that was already there (!) - I just couldn't hear it! No, the type of effect I can only recall hearing once or twice before, most notably when changing from a competent but not top-notch turntable to a very good turntable (e.g. Linn Sondek). The better turntable giving the impression of being 'louder' because of its superior (actual in that case) detail retrieval.

Interstitial silence on the sound stage is also much more correctly reproduced. Again, the 'humming' room being significantly quieter in the mids and highs. This lends a delightful air of 'reality' to the overall presentation, particularly with classical music.

The RoomLens folks claim significant improvements with 5 devices in the room as compared with 3. True, there is an improvement in the width of the sound stage, and the 'cleanliness' of the overall image yet again. Would you pay the asking price of $US395-00 per extra resonator? Nope - but at DIY prices, it is well worth the small extra effort and expense ($US30 for two). A little more for the satin black paint to finish them.

It has been said that they do not work at their best with other room treatment devices. This is not my experience, and I have been using them successfully with bass traps in the front corners of the room (behind the speakers). Yes, I have taken the other room treatments out of the room, and the resonators still perform well, but there is not the bass control that I would like. I say 'like'. I do not necessarily imply that my 'liking' is 'correct'. I tend to prefer a leaner bass, with more 'control' than (say) is produced by some types of box-construction speakers. Also, I don't believe that in my particular situation (or perhaps most) the two devices have overlapping actions. The bass traps work up to about 200Hz. These new resonators seem to work well above that frequency. So, they complement each other, rather than 'fight it out'.

How do they work? 'Intuition' points to Young's diffraction fields being formed in the room above 1.5 - 1.7 kHz. Adjusting the positions of the resonators adjusts the reinforcement and cancellation nodes of the diffraction field, and, judiciously done, this improves the 'random' nature of room vibrations in the mid-range, upsetting any tendency to sustain eigentones. The resonating tubes are also not parallel, and so we can expect the diffraction fields (thinking in 3D) to be non-symmetrical from top to bottom of the device, creating a little more interferential 'chaos' around the devices. The resonating structures themselves, being 'stuffed' and different heights, and 'tuned' to different notes (sort of) like organ pipes, will create differential resonances with the principal floor-to-ceiling resonance(s), thus reducing the regularity of that resonance also.

Once again thanks Jon. The best $130-00 (AUD) I believe I have ever spent on 'sound reproduction' in terms of return for expenditure.

Regards,
Gary Jacobson

This post is made possible by the generous support of people like you and our sponsors:

Parts Connexion

---

[ Top of Page ] [ Contact Us ] [ Support/Wish List ] [ Copyright © 2025, Audio Asylum, all rights reserved ]

---

[ General ] [ Speakers ] [ Tubes ] [ Vinyl ] [ Digital ] [ Hi-Rez ] [ Video Asylum ] [ Cables ] [ Tweaks/DIY ] [ Music ] [ Films ]

---