It isn't so. The higher power isn't for higher SPL, or listening level – it is for operating in class A only in my listening levels, which aren't exceptionally high.
The local Pass Labs dealer once borrowed my power amp in order to demonstrate it to another client. Meanwhile he left me Pass Labs X200 (class AB). I didn't like its' sound so much, however I heard what higher power can do (more holographic, 3 dimensional, sound stage, or presentation).
Right now I have no high efficiency speakers that I like. Should I find ones, I have no idea yet about how they will be build, horn or not. Should there be high efficiency speakers which I'd like their sound – they should suit the dimensions of my listening room.
In any case, I cannot say how such speakers should be built, horns, waveguides, upside down, or whatever. I know that cannot design speakers, so I'm not going to try.
1. I'm not looking for cost effective – I'm looking for the best possible sound quality that my finances allow.
2. On my previous sound system, recording made from vinyl to PC and played back were indistinguishable from the original vinyl. My sound system was upgraded since I made that test. I'll have to repeat it on my present system. If now the results will be similar, or close – I cannot wish for more, concerning digital playback sound quality.
3. I have already a CD player that I like.
4. Others' considerations are theirs. I follow only my own considerations.
Lynn I'm curious if your thoughts on DHT SET amps have changed since you wrote the Amity and Karna articles now that your new speakers are much more efficient than the Ariel?
I was very pleased, actually. Currently the system is apart for driver measurements.
It has been more than two years since I last heard the 288-H, but at that time I found the regular 745 to be so much of an improvement that I didn't keep the 288-H's. To me, the 745NEO/be sounds much better than the regular 745, especially in the area of tone and low-level presence. Even without re-working the crossover, the transition between the woofer and the cd sounded quite good.
I am currently in the process of measuring and evaluating GPA 416 and 515 drivers (Classic Series alnico) as candidates for replacing the TD15m in the upper cabinet (3 cf sealed, 75 Hz - 700 Hz). Once the outcome is clear, I will start working on the new crossover. Only when that is completed will I be able to really tell you what the low-level performance and presence/tone is like. The challenge here will be to get the woofer to keep up with the cd/horn. I suspect that the 515 has the best chance.
There won't be much time for audio tinkering in the next two weeks, though. I'll be in the pit for Nutcracker rehearsals and performances each night through next Sunday (playing timpani), then a week of conducting for the following weekend's symphony concert. Tis the season!
Gary Dahl
Well, that definitely constrains things. You have room that's a bit smaller than mine, and have low-efficiency speakers. Unless you change speakers, tube amps will be marginal at best. If you love the speakers you have now, any improvements in your system will come down to amplification and the front end.
The last commercial speakers I bought with my own money were the AR-6's I had in college in 1972. After that, it was loaner KEFs from Audionics, and after that, my own designs. The speakers I did for Audionics were fairly mainstream, but the Ariels of 1993 took me away from the mainstream of high-end audio, with the combination of a Spendor/Harbeth balance, very narrow and low-diffraction profile, and a true 92 dB/meter/watt efficiency.
I'm not a good position to advise anyone that owns store-bought loudspeakers or amplifiers. I know the sound of my own speakers because I know what's in them, the compromises I made at the time of design (driver availability, size constraints, lack of knowledge on my part, test limitations, etc.), and living with them a long time (in several different houses with different acoustics).
I've been living in this corner of audio long enough that commercial speakers sound odd to me, with Avant-Garde, Wilson, Focal, and Magico just sounding downright weird. I don't know why anyone buys them, except for the glowing reviews they keep getting. They sound awful to me, no matter where I hear them, and the measurements aren't that great, either. I'm puzzled why anyone in this forum would want to copy them.
I rely on the subjective impressions of Gary Dahl and Gary Pimm for the simple reason we have similar tastes and I've heard their systems in their own homes, and they've heard my system in my house. So we can share subjective impressions and areas for improvement that we'd like to work on. Our systems are not identical, since we have somewhat different priorities and different approaches to solving problems.
When Gary D gets his dual-woofer setup going, I'll be very interested in hearing his assessment of dynamics. Why? He plays one of the loudest instruments in a symphony orchestra, the timpani, and I've been in a practice room when he was wailing away on them, standing no more than a foot away. They didn't seem to sound all that loud (the typical acoustic-instrument experience), but you could certainly feel the drum thwacks in your body. The pitch and spatial perspective from drum to drum was also very clear and natural (unlike the blurry impression from most hifi systems).
If the new speaker can get anywhere close to that experience, it's more than good enough for me. I have no interest in reproducing the on-stage experience of a rock band; that's hearing-damage territory, not going there. My days of going to rock concerts are decades in the past (although I did get to hear the Beatles live in Hong Kong, and the Grateful Dead at UCLA in Los Angeles).
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I does. Especially if you only want to use it down to 75Hz. Tho how you will do that in 3 cubic feet sealed, I don't know. The 515 is a very dynamic driver, FWIW.
I will be following Gary Dahl's setup with great interest. One possibility that I might try is removing the back wall of the 515 sealed box, and almost completely filling it with recycled-cotton UltraTouch filling, in the style that Gary Pimm was using for his Beta 8 midbass drivers.
If there is a secondary bass-fill driver below the 515 open or sealed box, that can neatly offset the falling response of the 515 (which has an extremely low Qts). The secondary driver can also take advantage of the floor image to raise efficiency.
If there is a secondary bass-fill driver below the 515 open or sealed box, that can neatly offset the falling response of the 515 (which has an extremely low Qts). The secondary driver can also take advantage of the floor image to raise efficiency.
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The extremely low Qts of the 515 Alnico results in a Lowther-like sloping response. In normal applications, this calls for horn loading to straighten out the response, but the secondary woofer lets Gary play around with crossover overlap to offset the falling in-room characteristic, while retaining the upper-bass virtues of the 515.
The question in my own mind is the effective in-room efficiency of the secondary driver. In Gary's setup, it'll be independently powered and have its own active crossover, so all he has to do is turn knobs, measure, and listen. The effective efficiency of the secondary driver depends not only on the floor image, but the proximity of images from the back and side walls, as well.
The question in my own mind is the effective in-room efficiency of the secondary driver. In Gary's setup, it'll be independently powered and have its own active crossover, so all he has to do is turn knobs, measure, and listen. The effective efficiency of the secondary driver depends not only on the floor image, but the proximity of images from the back and side walls, as well.
I've mentioned doing a system capable of 132dB peaks cleanly as a project, and people start spinning their finger ... . But if you want to replicate that experience cleanly, that's what's required.
Hi Lynn,
Thank you.
Indeed. 30 Watt per channel (KT88, triode mode, PP) wasn't enough.
Also, I made a mistake in my previous post, the height of the room is about 3.52 meter.
It looks this way.
We are on the same boat here.
Again we are on the same bout.
I'm not looking for more than the SPL of a symphonic orchestra from the balcony, at back of the hall (which is where I usually sit in concerts).
Thank you.
Indeed. 30 Watt per channel (KT88, triode mode, PP) wasn't enough.
Also, I made a mistake in my previous post, the height of the room is about 3.52 meter.
It looks this way.
We are on the same boat here.
Again we are on the same bout.
I'm not looking for more than the SPL of a symphonic orchestra from the balcony, at back of the hall (which is where I usually sit in concerts).
Measured the GPA 515-16C's last night and entered the parameters in the sealed-box calculator on mh-audio.nl. The sim shows a system Q of about .77 and is -3 dB at 63 Hz in an 85-liter box. This is low enough for my purposes. In fact, Lynn has suggested using a high-pass filter in order to reduce out-of-band excursion and minimize IM distortion.
In the same box, the sims show the GPA 416-8B's yielding a system Q of about .875 and a -3 dB point of 57 Hz.
My original thought was to try the 416's in the bottom cabinet (5 cf tuned to 23 Hz), which currently houses the TD15H, retuning as needed. Not a great idea, as it turns out. The 416 really needs a much larger box.
The TD15H is perfectly happy in the bottom box, -3 dB at 43 Hz. The main limit on its performance has been the plate amp, nothing special. It will be replaced by a Parasound HCA-1500A amplifier and QSC DSP-30, which will make it possible to tailor the in-room response more effectively.
Gary Dahl
In the same box, the sims show the GPA 416-8B's yielding a system Q of about .875 and a -3 dB point of 57 Hz.
My original thought was to try the 416's in the bottom cabinet (5 cf tuned to 23 Hz), which currently houses the TD15H, retuning as needed. Not a great idea, as it turns out. The 416 really needs a much larger box.
The TD15H is perfectly happy in the bottom box, -3 dB at 43 Hz. The main limit on its performance has been the plate amp, nothing special. It will be replaced by a Parasound HCA-1500A amplifier and QSC DSP-30, which will make it possible to tailor the in-room response more effectively.
Gary Dahl
I don't have a specific target for maximum system output, but I do want a big, dense soundfield (when the program material calls for it) and a sense of effortlessness. When listening to orchestral music, for me there is a point where turning it up louder makes it sound less realistic (even if the system isn't under strain), so I'm not interested in going further. But for music that is normally performed with amplification, I don't notice that effect nearly as much.
My timpani don't seem all that loud to me while I'm playing them. I believe there is a psychoacoustic effect that alters my perception, because I always know when to expect the sounds. In a new piece of music, nearby players may have trouble with unanticipated loud sounds.
Being in front of a brass section that is "letting it fly" is another matter entirely. That can be really loud from the podium…think of those poor viola players! I was once in the orchestra pit during a dress rehearsal of Götterdämmerung at the Seattle Opera…unbelievable. We (and most other orchestras) use clear sound shields in strategic locations to make it as safe as possible.
A system that can do 132 dB peaks cleanly would not be a bad thing as far as I'm concerned, as long as its other musical qualities aren't compromised. But I would rather not listen to it that loud. Now I'm curious about the actual loudness of the music around me…hmmm, there's an app for that!
This is generally due to the way measurements are conducted. Based on the information passed on through education, the types of measurements are used to see if you meet a minimum criteria, troubleshooting measurement techniques and how to process data to reveal problems is a skill accomplished through determination to improve real world performance. Normally these techniques mean nothing to someone with no real world experience.
That's probably to do with this - Acoustic reflex - Wikipedia, the free encyclopedia
Also, this: http://www.speech.kth.se/prod/publications/files/qpsr/1982/1982_23_1_031-048.pdf - quite a solid study ...
If the speaker was 100 dB/meter/watt efficient, the amplifier would have to put out 1600 watts.
That's an appalling thought.
Not only would I not want to be in the same building, I wouldn't want to be in the same neighborhood.
Ahh hah! I take it you declined that invitation, from Basspig to a musical evening ... Why We Need Sound Above 120 Decibels ...