Saturday, August 7, 2010

The way I like speakers these days

Part III - new open baffle speakers which made me sell my Lowthers

I was listening to Lowthers on open baffle for years. Recently I became restless for something new and started searching for new drivers. I knew from the web people liked the B&G Neo3 planar tweeter. Especially with back cup taken off in dipole position. It has flat response, exceptionally good of-axis response, decently high sensitivity (~93dB) and its not outrageously expensive. Next thing was to find the midrange. I searched a lot of pages, and after a while I selected Fostex FF125K. The main reason I like to use "full-range" as a midrange is because I like to cover the widest possible range by it. I like small midranges, I always preferred the sound of small midrange in comparison to big one due to lesser breakup modes at higher frequencies and less beaming. I wanted to match excellent polar response of tweeter and only small midrange can do that seamlessly. This little full-range is amazing on its own, but if you do not overload it in the low frequencies, it will reward you with even more detailed and refined sound. Tweeter and midrange were placed on small open baffle, as usual, and on top of closed box woofer. Woofer is 15" Jamo. Whole system is bi-amplified, active crossover (my own construction based on Marchands LC passive crossover buffered with class A buffers) splits the signal at ~150 Hz, top is powered by Aikido octal preamp and OTL Transcendent amp.
Woofer is powered by Pioneer receiver.

These speakers beats the Lowthers on open baffle in any parameter, especially neutrality. As you know, Lowthers have few peaks of uneven response, especially 4 and 8kHz shout, which can become annoying after a while. I use 31 band Ultracurve to deal with these peaks, but the solution is not ideal. In contrary, the Neo3 and FF125K combination needs very little eq, breakup peaks of FF125K are removed by crossover and the transition to tweeter is great. This combination has more uniform off-axis response, which leads to better and more solid stereo imaging. Everything is better, even power handling. You had to be careful with Lowthers at higher volumes, these speakers are more power friendly, you can play them louder withou a trace of distortion. Pretty high efficiency too, not as Lowthers, but high enough. Bi-amplification takes care of lower woofers efficiency, so no problems here.
Anyway, I am very happy with these speakers and do not miss Lowthers at all. It was time to change main speakers anyway, and this was big improvement. Hard to think of whats baffle bass perhaps? To make it full dipole sound? Who knows. Enjoy the music. regrets of selling Lowthers. I have added midwoofer, to ease the great sounding 4" midrange, which excels even more now. New 10" midbass covers just the slam in the 150Hz to 300Hz. It helps a lot. This make my main speakers effectively 4-way bi-amplified system. It handles even more power, has lower distortion, greater dynamics. I love it. Here are some pics of system a the moment.

Saturday, July 17, 2010

The way I like speakers these days

Part II - vintage Magnavox on open baffle on top of closed box woofer

One day I came across amazingly sounding 6x9" Magnavox mid range driver. I always liked the sound of this little oval speaker for amazing detail, speed and sensitivity. When compared side by side, other midranges were lacking the richness of tone and balance. Especially the balance is great, it is free of any breakup modes. I believe its the oval shape which does that. So I put this midrange on open baffle and accompanied it with the best sounding tweeter I could find. Surprisingly it is vintage Bose paper cone tweeter. As much as I hate Bose for what they have done to audio these days, this tweeter came from big old thee-way floorstanding speakers and sounds great. It matches Magnavoxes high sensitivity. I placed these on top of closed box with 15" woofers per side. The boxes came from vintage Grundig speakers. System is biamped with tube amp powering the open box panel and solid state for woofers. I have always noticed big improvement in bi-amplification, because it allows low power SE tube amps to shine.

Friday, July 16, 2010

The way I like speakers these days

Part I - B&C coaxials open baffle on top of closed box woofers

This is a concept I like a lot these days. Off course there are many ways to make great sounding speakers, this is definitely one of them. I like open baffle speakers, especially in midrange. On the other hand to achieve deep bass with open baffle is difficult. So the woofers are in closed box, which make speakers relatively slim.

I obtained 12" B&C coaxials from parts express for $50 each, the woofers are 15" Jamo for just $15 each. So for just under $100 per side one can put together extremely good sounding speakers. They are clean, coherent, dynamic and efficient. Few watts is plenty. They would, just like many other speakers, benefit from bi-amplification, which is going to happen soon.

Tuesday, June 22, 2010

Aikido Octal and Transcendent OTL

Match made in heaven?

I have just finished Aikido preamp with 6SN7 tubes. I am testing it with Transcendent OTL amp. Sounds promising. The SE OTL amp itself does not have enough gain to be used without pre-amp, hence I was waiting for something to pair it with. So far the clarity of tone is amazing. Heights are limitless, but the bass is lacking a little. Its no surprise, since OTL is only 2 watts. These will be used later in biamped system with some solid state for woofers. It would be heresy to use SE OTL to drive woofers. Anyway, I am pretty happy with the pair so far. Its a work in progress.

The pair together, Aikido without cover.

Pretty straightforward build and easy to put together.

These are the speakers I was testing it with, a B&C 12" coaxials on the top, open baffle, and two 15" woofers per side in closed boxes. The way I like speakers these days. Source of the signal is small Yamaha tuner, not visible, but quite good sounding, I just align it.

Friday, May 14, 2010

Small open baffle speakers

I made these speakers from spare drivers...mostly. I had 12" Blaupunkt subwoofers, than I had four 4" Tesla midranges. When I have seen Dayton 2" dome midrange on sale, I could not resist to finish it with Dayton drivers. So the dome mid and tweeter are Dayton.
These speakers sound wonderful. Woofers are in closed big box, bass is deep and well defined. Mids are clear and open, yes, open, you expected that. Tesla midranges are from old socialist era some hifi leftovers. Dayton gives its presentation extra shine in upper mids, tweeter is sparkly sweet. I like these speakers a lot. Maybe because they are driven by old Tandberg receiver, which I believe sounds way better than any modern receivers.I compared Tandberg to many other receivers,I like this best. Speakers are actually wasted in this setup, they could easily satisfy as main speakers. Dynamic, precise, clean with low distortion. Highly recommended.

Btw I do not like any of that dolby pro-logic 5-channel crap. It degrades sound so significantly that its painful. Any proper sounding two channel stereo gives me more sound enjoyment for good movie than five crappy little speakers shouting around like a mad dog. Sound coming from behind the head is just annoying when the screen is upfront. Two well done audio channels project better stereo anyway. Just my observation.

Saturday, April 10, 2010

PA speakers

I made these speakers for my musician friends, colleagues at work, who formed music group "Coomasie Blues Band". These speakers were made for their rehearsal and small venue concerts. These speakers are made of 18" high power PA woofer per side, four 6" Dayton PA midranges, Radian 485 2" compression tweeter and Selenium supertweeter.
Speakers are very efficient, sound is powerful and authoritative, but not flat. Woofers can not keep up when it comes to the efficiency with the rest, radians are most efficient and have to be tamed by the L-pad. Open baffle midranges give the speakers clean sound, especially for voices, which these speakers are mainly used for. Much better than if voices are handled by 15" PA woofer.

These speakers are powered by Behringer 2500 watts amp and use Behringer Ultracurve equalizer. You can see the eq required to make these speakers flat in the living room. Radians need to be lowered as most efficient, woofers roll of too soon, but that's fine for PA, especially if these are for vocals mostly. One has to be gentle with volume control, as it goes loud very quickly. At one party we tested the speakers a was unbearably loud at 50 watts only, so efficient are the speakers. I once powered the speakers with 2 watts OTL tube amp, that was all needed for normal listening. Ideally one should biamp these speakers.

Update...these speakers were converted into domestic, since the music group no longer performs. Tweeters were too high, so I moved them lower to the ear level, Radian horn was not needed, was removed and sold, and crossover was simplified and optimized using Holm Impulse software. I added external crossover into wooden box. Bi-wiring is possible. Speakers sound exceptional, highly efficient, dynamic, yet balanced and pleasant sounding. They sound good quiet or loud, they do not care, they just play nice music. NIKKO high quality electronics helps too. Some pics...

Friday, April 9, 2010

Big open baffle speakers

Blast from the past or Magnavox revenge...

I had quite a few Magnavox speakers laying around. So I decided to put them all on open baffle. They turned out wonderfully. Amazing clarity. Everybody who visits wants to hear them and everybody is amazed. Such dynamic and crystal clear open sound. Speakers are made of two 15" woofers per side, crossed with 5.5 mH inductor, one 12" midbass crossed with 150 uF bipolar capacitor, one 10" midrange crossed with 40 uF capacitor and a horn tweeter crossed with 2.5 uF capacitor. So the speakers are actually not completely open baffle, since the tweeters are not radiating back. But who cares! I have not measured the efficiency of the speakers, but trust me, must be close to 100 dB/w/m. Speakers are powered with fully restored and upgraded Magnavox, what else, push-pull amplifier 20 watts per side. That is enough to make ears bleed.
I can finally enjoy Carl Orrf's Carmina Burana or Verdi's Requiem in concert like scale I once experienced live.

...and here are some pics from above mentioned fully restored Magnavox amplifier...

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Wednesday, February 24, 2010

Line array speakers

I obtained about twenty midrange drivers on fleabay for $1.98 all! Yes, they had some blemishes. Yes, I had to pay shipping, but still, these were quite cheap speakers. The speakers are Foster, 25 watts continuous, 45 watts music. I arranged the midranges eight per side with power tapering and resulting impedance of 6 ohms.
I used LineSource tweeters, six per side, no power tapering, as close to each other as possible, with resulting impedance of 6 ohms. After first listening tests I decided to use super tweeter (Cervin Vega horn) in the middle. It sounded better that way.

Since the line arrays are quite sensitive, I had to use two woofers per side. Woofers are two 15" per side in parallel, wired for 4 ohms, to help raise sensitivity. Woofers do not go as deep as I would like to, but they match the sensitivity (and they were cheap).
Whole system is bi-amplified with tube amp powering the midrange/tweeter section and solid state receiver powering the woofers.
These line array speakers sound great, they are dynamic, very much like live music, they love the power. They do not suffer the constipation of normal speakers when pushed hard. Its the woofers which run out of pace first. At normal levels speakers barely move, so the speakers sound very clear and relaxed. You can be close or far, you can hear them well. I can be anywhere in the room, yet I can hear great soundstage. I like line array speakers. I can hardly imagine how they would sound if high quality drivers were used (like those in Genesis).

Monday, February 22, 2010

HOLM Acoustics

Absolutely excellent program for frequency response measurement can be downloaded from HOLM Acoustics web page:

Briefly tested my second system, this is what I got.

Sunday, February 21, 2010

Lowthers on open baffle

Why? Quite a few reasons. Mainly I am attracted to simplicity. Plus I am lazy too. Only the simplest can reveal the most complex. There is no simpler speaker arrangement than open baffle. To me enclosure and crossover are unnecessary evil. No enclosure is best enclosure. As well as no crossover is best crossover.

Lowthers have been used in almost any possible arrangement. Large closed enclosure, bassreflex enclosure, mostly backloaded horn enclosure, Voight pipe, transmission line, front loaded horn and so on. I have been listening to Lowther on open baffle for more than ten years now. Finally there were other people putting Lowthers on open baffle, thanks to Dick Olsher and Bert Doppenberg. Lowthers sound on open baffle very transparent, fast and alive. Very much like live music. Side cancellation sharpens the sound beam thus preventing reflections from the nearby walls. High directionality brings clarity. Reflections from the walls, those reaching listener within first ten miliseconds after direct signal, are almost eliminated by open baffle arrangement. Sound radiated towards back of the baffle is no problem, when it reaches listener it is already delayed by a significant tens of the miliseconds and diffused enough. Actually, it is giving spaciousness to the music, a feeling of reverbation in the room without obscuring the original front signal.
Once you will hear a good open baffle speakers, like those from Audio Artistry or Genesis, you will never go back.

Saturday, February 20, 2010

Headphone amplifier

Nothing puts you closer to the music than headphones.
However, to reach this intimacy, good headphones must be driven with appropriate headphone amp.

Most of the people do not like headphone listening. Either because headphones are uncomfortable to wear for them, or most of the time they do not like the sound. And I do not blame them. Most of headphone outputs suck. CD players and cassette decks usually have outputs without volume attenuator and even if they have, the sound is just awful.
But it does not have to be that way. Theoretically headphones should allow you to be closer to the music, more intimate, not disturbed by outside noises. Furthermore, it should be easier to cover the whole frequency spectra with one voice coil, no crossovers,no phase shifts; not influenced by room acoustics, just the recorded sound; should be easy to drive, just a couple of milliwatts...
Why it is not that way?
As I said, to reach this intimacy, good headphones must be driven with appropriate headphone amp.
When it come to headphones, I settled with Sennheiser's HD580 and Grado's SR325. I am not saying that there are no better cans, but these are exceptionaly good. They are just like jin and jang. Two different wolds. Grados are neutral, well balanced, deep powerful bass is combined with extended heights, clean and precise sound. Very dynamic. Their 32 ohm resistance can be a problem for high output impedance tube amps. But I use them often, sometimes I have a taste just for this precise presentation. Sennheisers on the other hand are lighter sounding, nice soft heights, generally more lush and sweeter sounding. Might be too sweet and light with some tube amps. Very pleasant to wear unlike Grados.
Headphone amps?
I have Musical Fidelity's X-Cans, excelent headphone amp. Plus I built a couple of headphone amps myself. Each amp sounds differently. As well as each headphones. So there is a lot of combinations to explore.

This tube headphone amplifier is a combination of Eric Barbour's and Kurt Strain's constant current/mu follower. Amp uses two 6SN7 tubes per side. I tried various power supply versions, solid state rectifier for high voltage and rectified and filtered heaters worked best. Sound of this headphone amp easily beats Musical Fidelity's X-Cans. It is warm, soft, euphoric and clean and dynamic at the same time. I bet it has a lot of second harmonic distortion, just what I desire. I have no way to measure it. And I do not care how it measures, it just sounds great. Never heard anything more euphoric, pure listening bliss!

Update...I have recently converted two tube amplifiers into headphone listening as well, besides the speakers. Using direct signal from the tube amp to power headphones is wrong, complete mismatch of impedance and sensitivity. Transformer coupled output has secondary winding designed to see certain impedance, usually 4 to 16 ohm, which is expected to be on the output for proper operation. Plugging 150-300 ohm headphones will result in increased noise, hiss, hum and may damage headphones with too high signal, and even worse, your hearing. Headphones are just too sensitive and require only tens of miliwatts. If you have headphones with 16 ohms, which is just wrong move on the side of manufacturer of these headphones, because plugging of these to normal jack in the mp3 player or cd player powered by OPA, will result in the OPA overload, be careful, as you may have too much signal to damage the headphones and your hearing, as said above. Easy solution is voltage divider, see picture. You present amplifier with proper impedance and take small part of the signal to power your headphones.
If you have capacitor coupled OTL amplifier like Transcendent SEOTL, you may find other resistor values to work better than for transformer coupled amp, so some experimentation is required. Below in the picture is what worked for me. I do not understand why Bruce suggests to wire headphones directly to this amp, doesn't he listen before he gives and advice? Try both ways, directly, and you will have buzz, hiss and too much sensitivity issue; and with simple voltage divider, and you get pure listening bliss to one of the best sounding amplifiers...good luck!