Bottlehead Forum
General Category => General Discussion => Topic started by: drewh1 on March 24, 2013, 05:38:35 PM
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Alright, a disclaimer, I've had a few glasses of wine . . .
I know some of you guys have been at this awhile so I need your input.
So this whole Bottlehead thing has thrown me into a hi-fi crisis. I really love my current system and of course am always looking for improvement. I built the Stereomour thinking it would be a nice alternative amp for listening to at lower volumes late at night. Unfortunately, its sound is too good and has opened up a whole dilemna for me.
I like most things about the sound of the Stereomour, but really prefer the bass and the clarity of the Ayre (it is very defined and realistic) Vocals are better on the Stereomour (of course). Also, my speakers are not super efficient, so I probably don't get the best out of the Stereomour. My speakers are really very good otherwise and I would be hard pressed to better them without spending a lot of money. Money is an object although I am willing to spend quite a bit on my music. I was a professional musician for awhile, you won't believe what a good acoustic bass costs!
So my questions are, Do I?,
1. Accept the limitations of what I have, sit back have a drink and just enjoy it?
2. build some high efficiency single driver speakers?, (I don't want to get in to horns). I think building high performance speakers is a much bigger challenge than building an amp.
3. Roll tubes in my Stereomour until I find a combination that gives me the vocals and bass that I want.
4. build Paramounts (still have the tube rolling issue)?
5. Get a girlfriend and forget about all this hi-fi stuff?
thanks for reading this and I appreciate your input!
drew.
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Hi Drew, but in the mean time, get started by reading through the blumenstein audio thread in the speakers area on this board.
I've been though this, come from roughly the same place in terms of backgound aas you and have been down just about every audio path you can imagine. I think I can help.
-- Jim
I'll contact you offline tomorrow
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Well, I've had a stiff drink or two myself - hey, it's Sunday night! - but I'll drop a comment or two anyhow. Subject to change tomorrow of course!
Bottom line, a good part of the bass and clarity you are missing is due to the lower power and the lower damping factor of SET amps.
Clipping of transient instantaneous peaks is very gentle with SETs and is much less obvious than clipping of a high-feedback solid state amp. But it does damage clarity. The only solutions are to get a more powerful amp, a more efficient speaker, or listen at lower level. (The last is never quite satisfactory if you are intimately familiar with the sound of an acoustic instrument and want to reproduce it - long ago I was a cellist, so I have some idea of where you're coming from on that front.)
The low damping factor will often make a speaker that was designed for solid state sound a bit muddy - the bass resonances are boosted a few dB. It's not enough to be obvious as boominess or "one-note bass" but if the speaker/room combination is really good then the change will be for the worse. Sometimes simply re-optimizing the speaker location is enough to deal with this effect, since room resonances are much larger than speaker system resonances. Otherwise, again only a speaker better matched to the SET characteristic will do the job fully.
If you would identify your speaker, and its efficiency/sensitivity, and perhaps give us some idea of your room size and listening preferences (types of music and loudness), the Forum has quite a large amount of collective experience to offer in support.
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Hey Paul - thanks for your comments - Nice to share a drink with you. I switched to cello after playing bass for many years - always felt cello was really my instrument and did get many years of enjoyment out of it. For a while, I was travelling to Europe on business and found my way to the instrument auctions in London. i had the opportunity to buy and sell a few really nice cellos. My last cello was an old tyrolean with a full curved back. Had a nice low C, not a solo instrument though. Just listened to the bach suites on the Stereomour.
I don't find clarity in the mids and treble to be an issue at all with the Stereomour, in fact I am very impressed with everything this amp does. My other amp is a zero feedback SS amp. As a musician, I value timbre more than many other qualities and find that reproducing timing of the attack portion of a note is critical. The DAC I use also has filtering that eliminates (supposedly anyway) pre-ring and reproduces attack and timbre very accurately. The Stereomour very accurately reproduces piano and strings. (Cello sounds great on it). I have definitely lost clarity and impact in the 50 to 200 hz range though.
My speakers are Green Mountain EOS HD's. I went through a lot of speaker to get to these. They are 2 way with first order cross over, time aligned. Cabinets are designed to eliminate box reflections. These are the closest I have heard to electrostats. 90 db (4.6 ohm) but apparently pretty easy to drive. I use a pretty solid DIY sub for everything below about 55 hz. I have spent ALOT of time integrating the sub and get a very good reproduction of an acoustic bass with the combination.
Maybe I am just reluctant to throw out what I have invested time energy and money into. I have been looking at building a pair or Metronomes (see frugal horn site) with Fostex 208eZ (96db) I can't hear much above 12 khz anyway, so I think FR drivers might be the way to go.
My sense is you have been very involved in the single driver world so maybe you are familiar with the Metronomes.
anyway, I am going on to long now, thanks for your post.
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You know, now that I think about it, all the options I listed in my original post are pretty OK!
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Ok, My humble opinions in order:
1) always a good thing to help you relax into the music
2) High efficiency single driver speakers will give you dynamics, detail, beautiful voices but still need reinforcement on the bottom
3) you are going to roll tubes anyway so let's keep this on the back burner till you get 100 hours on the stock tubes, or till you need a new tube
4) Paramours Paramounts (I didn't have enough coffee when I wrote this) will sound even better in stock form than the Stereomour, it is more refined. IMHO, I am doing well with 2A3 Paramours in a good sized room, 13' X 23'.
5) Do what I did the second time around, find someone who enjoys the same music you do and both listen, smooch, etc.
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Thanks Grainger - All good sensible advice :) - I am going with it (for now)
drew
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My advice may be counter some others, but I just can't help it. I DO know what you mean by saying it took you a lot of going through speakers to get what you wanted in the first place. On the other hand, some of the most fun I had WAS going through equipment. I have ended up with single driver speakers, and wish that would have found them years ago. Most of the designs are an easy build, allowing more of the driver budget to be used on the cool stuff. Grainger is right about needing bass reinforcement if you go that direction. I see that as an opportunity to place a sub where it needs to be, rather than where a full range speaker might be placed. I agree strongly that bass must be reproduced accurately if you want music, not thump. At that juncture, other considerations become important, such as room acoustics and the like. I am still working on producing a higher quality bass from my system. To conclude, my opinion is that new speakers may give the most improvement in a system provided that you haven't already realized that with your present speakers.
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Greg - Thanks for the thoughtful input. This really is the most useful and congenial forum I have ever participated in. I have been considering FR drivers for years and so I think the time has come. The Stereomour is good enough to give me the kick in the pants.
Do you have any favorite designs or drivers you have encountered? I was thinking of the Fostex 208eZ - efficient enough although it will probably need the addition of a super tweeter, I have heard good recommendations on it. Nice thing is I can try multiple designs. Although birch plywood isn't cheap, I can buy alot of it for what I paid for my current speakers. Or I could borrow from the Orcas and try Bamboo.
I really would appreciate your opinion on designs.
drew.
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Thanks for the information; fortunately Green Mountain shares a LOT of information (after you winnow out the marketing talk). They appear to have implemented quite a number of my own prejudices about speaker design, so it MUST be good! <-- that's a joke, son.
I agree that the load should be quite suitable for tube amps, with essentially no change in the timbre above the bass region. But in the bass, the damping factor issue will cause a broad hump, probably around 2.5dB and spanning more than an octave, from about the original cutoff to twice that frequency. That's broad enough to be quite an audible change.
A fairly easy experiment is to reduce the port area; this will tune the port a bit lower and reduce the hump. It's not completely optimal, and will naturally require re-optimizing the sub integration, but it can tell you whether that's the source of what you are hearing. You want something like 35% area reduction. If the ports were straight, I'd suggest some short lengths of 5/8 dowel, but given the curved and bifurcated port design that would probably not work too well. Perhaps some felt lining the accessible portion of the ports; I'd guess 3/16 thick to start with. It's easily reversed with no risk of damage, anyhow.
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I'll give it a try -Roy from GMA (who apparently follows the forum) sent me an email that he has some ideas too. All of this is quite a learning experience.
I do have one quick question - I have found that proper phasing of the sub is critical to integration - would this be affected by changing amps? - cables and lengths are all identical but it is powered by speaker outputs so this might be something else to investigate.
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Phase is a really easy experiment - just swap the speaker cable connections. You'll hear the difference, no question! There is no way to be sure whether an amp is in phase or out of phase with the input signal, the specs are just not always correct even if there are some. That's the real reason I like banana plugs... :^)
I could tell you that most of our preamps reverse phase, and most of our power amps preserve phase, and I'm probably right unless you crossed up some transformer terminals or my memory slipped up. But it's way better to test it yourself. You may even discover that - in your room with your music and your setup, the "wrong" way sounds better. It happens.
You know, I spent a career in acoustical research. Did an awful lot of mathematics, and I always mixed up the phase on complex numbers, it's just way to easy to do that - physicists use i and EEs use j for the imaginary unit, and i=-j, and acoustics draws about equally from both disciplines. So I learned to ignore the problem until the very end, then try the result both ways and select the one that looked most plausible. Much more reliable and much much faster than making a theoretical analysis! If anybody pointed out an error I made, I just said "thanks" and made the change. Didn't happen very often.
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When it comes to OB designs, I am a little green. I have tried a few drivers, and on the whole, I find most of them to have a bit of shout. It's too bad really, because other than that, I really love them. For me, I found this design to be the best by far so far. It is an OB design, but makes use of a sort of tuned Hemholtz(sp?) resonator. It does need help sometimes in the bass region, but with the driver that I am using, it sports a tone control by using a audio transformer with two different taps. Bottom line for me, I'm no longer looking for that speaker that gets it right. I built it out of Baltic birch plywood, rosewood, with 1 1/2" thick cherry baffles. No doubt there are a sea of options. The design may be viewed at Decware.com
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Hey Paul - I meant the Phase on the subwoofer only - My sub is located in a corner of the room and has a long run of speaker cable so it ends up being quite a bit off from the mains. The main outputs are fine. I can tell out of phase pretty quickly, I even got all wound up because I put some Stravinsky on and notice the strings were on the right instead of the left. Thought I had mis-wired the inputs but just got the speaker cables backwards!
Oh and glad to hear you appreciated the GMA design concepts. It is a noticeable difference to move the tweeters into a time aligned position. The imaging of vocals becomes very accurate, just like the singer is standing in the room. BTW, either my ears are adjusting or those caps are "breaking in" but I am enjoying this amp more and more.
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Greg - those OB's look beautiful - I would love to see a bigger picture of them. What drivers ARE you using?
I'll check out the Decware site. it is clear I need to spend some time listening and getting opinions/ideas. There are a lot of great DIY designs out there, just a matter of getting the tradeoffs right I think.
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Oh and glad to hear you appreciated the GMA design concepts. It is a noticeable difference to move the tweeters into a time aligned position. The imaging of vocals becomes very accurate, just like the singer is standing in the room.
I have heard GMA speakers a time or two at Rocky Mountain Audiofest several years ago. They are spooky, almost like listening to headphones but with spatial effects that headphones can't provide. The only speakers from which I've heard a similar effect is a pair of 4" fullrange drivers (the old CSS FR125) in smallish ported boxes that I owned several years ago and listened to fairly nearfield (6 to 7 feet). That was before I moved to a SEX 2.0 and more sensitive speakers, but I still think sometimes about that sound and how I could get that along with the responsiveness and effortlessness of higher sensitivity drivers.
Point being, hopefully you can work it out with the EOS HDs, since I am guessing they have a similar unique and special sound to the ones I've heard. Either way, good luck and enjoy the journey.
Brent
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Hi Brent - Thanks for your post - the GMA's are quite unique, I am planning on sticking with them. In fact, I just got a phone call from Roy, the designer. He called because he noticed my post about finishing my Stereomour. Since I have had the EOS HD, he has redesigned and improved the crossovers, upgrading resistors and changing some values. He is sending me a pair for my speakers. Talk about service, Roy is a great guy and really a pleasure to work with.
So here is the philosophical piece:
I went through a period of swapping out speakers and amps every time I wasn't satisfied. Not only was it expensive and time consuming, it also never got the results I wanted since no single piece of gear is perfect, it is all about trade offs. The reason I turned to DIY was so that I could tweak and change things, try different interconnects without paying for marketing hype, build power cords, and now roll tubes. etc.
I am very pleased to be a part of the BH community because that is what this is about. Start with a solid, reasonable design, build it and then tweak it for your individual tastes (and budget). This is awesome. Although I am starting to eye those Paramounts, damn.
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So here is the philosophical piece:
I went through a period of swapping out speakers and amps every time I wasn't satisfied. Not only was it expensive and time consuming, it also never got the results I wanted since no single piece of gear is perfect, it is all about trade offs. The reason I turned to DIY was so that I could tweak and change things, try different interconnects without paying for marketing hype, build power cords, and now roll tubes. etc.
I am very pleased to be a part of the BH community because that is what this is about. Start with a solid, reasonable design, build it and then tweak it for your individual tastes (and budget). This is awesome. Although I am starting to eye those Paramounts, damn.
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I couldn't have said it better myself.
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Drew,
This sounds like a good plan -- let us know how the new x-overs work out. Aside from getting more powerful amps (not at all saying to not keep the paramounts in mind for the future), but you could always actively crossover to the subs and relieve the GMAs of some loower bass duties.
-- Jim
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Hey Drew - I'm coming in a bit late on this, and I, as well, have had some libations. Not continuously since the first post mind you.. but bear with me (Greg stop it). IMHO - take what you can get from the Bottlehead experience and go on with your life. Sure there will be some cognitive dissonance. Thats a good thing. The Bottlehead kit will open your mind to things of audio to help course your way. Not the answer. But the question will be more clear. It takes you down some paths that you may not have thought of without it. What I found is that the Bottlehead kit helped me focus my quest. On what is wrong, and what is right. Thats huge. Most posts that I read about folks who dont know what way to go with their system. They just know that its not good. - I guess I better quit while I'm ahead... Or have another scotch.
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Glad you chimed in Eric. Great comments, I had to look up Shiit gugner.
Well, right now, the sh((*)t sounds pretty damn good. So maybe I am wrong about caps breaking in. I am happy to admit when I am wrong. I have tweaked my sub settings and moved things around a bit, but I do think the amp is settling. Bass seems better, vocals and imaging are fabulicious. so screw the cognitive dissonance, this is fun!
Gonna roll an inexpensive driver tube, add a remote volume control and wait for my new crossovers. Might have to go back to the dating sites again, though this project has been an excellent distraction from that.
my gratitude to everyone for your interventions!
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Ok - Today my driver tube failed - amp just started sounding like a fuzz tone - presciently I had ordered a JJ ECC81 Gold Pin that came in the mail today.
So after scratching my head and remeasuring everything (it was all good). I thought I would try swapping in the new driver tube - worked.
It is incredible - this is a different amplifier. My theory is that the driver tube was always faulty and not working to spec ever. The bass is incredible with this tube, rivals my Ayre, there is more volume and clarity at the same time. I am really happy with this development -
I guess I would have discovered this anyway. This is what I can an amplifier, now I can sit back and really listen. :)