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In Reply to: Re: I think I have an explanation posted by fatbottle on February 26, 2007 at 08:35:09:
I am doing some active and some passive depending on what I have around at the moment. But the grand plan is totally active. I'll probably do the CD eq/boost passively with a cap and resistor in parallel. I want to keep both options (active and passive) around to compare. I'll use a recommended pro audio active for now. If active wins, as I suspect it will even with a pro audio op amp based one, then I'll see about building a nice tube crossover.The waveguide and compression driver is an 18sound XT1086 horn and ND1090 driver. The web site has very complete info. The mid range is an audax pr170mo. Madisound has a spec sheet. Just don't buy the claimed 100dB/meter crap. At the moment the woofers are borrowed 12" eminence in a bass reflex box. Crossover points are 250 and 1,800 hertz.
If it all turns out nice I might build a 45 set for the treble amp or I might use my 6v6 triode strapped one. I have made some plans to change an old dynaco over to a 6b4g amp using a driver much like Allen's PP1/2 which might become the mid range amp. For the bass probably my old B&K ST140. As you can tell nothing is fixed in stone yet:)
No, I don't think it has much to do with valves and sand. But it is interesting that when I go totally active the differences are less audible. I'll have to see if that still holds true when I bring the open baffle mid back into the equation.
Follow Ups:
Hi ,
Aha ! I assumed you had the DDS units . Hmmm , have you taken a look inside your 'pro audio' crossover yet ? May be a sea of crap electrolytic caps , 5532 op amps etc inside choking your sonics . You may find those HF drivers will need just a simple 1st order network tuned a little higher than (very similar pancake driver) on a 12" Dayton waveguide running like this . 1st order on HF , 2nd order on bass with a zobel . I've heard about those Audax driver specs but maybe a better solution would be to find a 12 or 15" that goes higher without breaking up and go 2 way . I'm having fun with the Tad TD 4001 now , had to implement a parallel trap to get rid of that shouty peak , with active I doubt I'll need this fitted . Now to find an affordable bass driver to do the things some justice . LOL this shit is never ending , isn't it ?cheers
Take nothing for granted with those pro-sound active crossovers. The first one I used years ago sounded absolutely hideous when first installed. After weeks of stuffing around, it turns out that one midrange channel was phase reversed. This is quite hard to figure out in a three way system.The latest adventure concluded yesterday. A few weeks back I borrowed an active crossover from a friend. He hadn't used it before. One midrange channel was 6db louder than the other. This took more time than you'd think to figure out. The speakers were new to me and I kept playing with the positioning because they wouldn't image.
Yesterday after more frustration due to the elusive nature of the good sound I would get occasionally, I realised it would be easy to measure once and for all. I used ARTA demo software and a laptop. Turns out none of the levels match when the controls on the front panel match between left and right AND neither do they track with each other so relative positioning is impossible. If you make any change, you have to measure to get within 0.5db.
On top of that, the crossover frequencies do not match between channels when set the same AND they are both more than 100% off from the front panel reading. I thought I was set at 400Hz, but instead I was at 700Hz on one channel and 900Hz on the other!
After setting it all using the measurements on the laptop, the sound is P0 better. Funny thing is that I thought the sound was acceptable prior to this. These are the dangers of speakers that are new to you and gear that lies to you. You just HAVE TO MEASURE or you're flying blind.
This is supposed to read: "After setting it all using the measurements on the laptop, the sound is 500% better."
You can say that again! But what else would we be doing, paying attention to the wife and kids? At least it cuts down on our drinking time.On the advice of djk, I have decided to give the TDM crossover a try. I am expecting it to be delivered today. I would have liked to get a 3-way but when I called the place they only had one left, a 2-way and for 50 bucks I couldn't turn it down. They sell new for 500 bucks or so. I had been using a cheap ART brand that I borrowed. The pro guys say the TDM is a good deal better than the behringer and guys like Thorsten have said they can live with the behringer.....so we will see how it goes.
Yes, life would be easier with a 2-way. But I rejected that as I felt it forced me into areas I can't afford (or didn't want) to go, like a TAD compression driver and costly horn or a sub woofer. I also wanted to bi or tri amp as I want to be able to play loud. I visited another inmate a bit ago and we were all so blown away by what his speakers that we all went home and started building speakers. Let’s just say we all learned on that day that serious music with serious bass requires serious wattage and a lot of square inches of woofer cone. He had four 15" and four 12". He also had the stage accompany ribbon tweeter. Check that out sometime. Insane power handling and very nice sound. Not too laid back like some ribbons can be.
Duke uses and likes the TAD woofer. If you find something from 18sound you like I can get good prices on them. The stuff isn’t cheap but some say their woofers are just as good as or better than JBL.
no matter how good, how cheap or expensive. You always learn something about the sound of your own system. I listened to a friend of a friend's system once and although it was really modest including his SS amps, there was one element of his system that sounded better than my all tube, full blown system. The good thing about it was that suddenly I knew what I was chasing and now it's no contest.Another time I'd gone round in circles and just plain lost my way. My sound was crap and I just couldn't seem to fix it. Again I listened to other systems and it helped reinforce the strengths and weaknesses of my own. I had direction again and it was easy to improve the sound. Yet another time I was in the US and visited a major audio show. Although not much impressed me there was one surprise or two and when I got home I immediately chased the missing element … wasn’t too hard to do.
If I've learned anything it's that subtle tonal differences can make or break a system. For instance it seemed almost impossible to get great bass without muddying the sound, and accentuating the highs certainly wouldn’t fix it. But I found a way and the great thing about tubes is that it's so easy to tweak the balance.
Russ, I'd be interested to know what your overall perceptions of your system's sound were at the time of your discovery between SS and tubes. How did the sonic weighting change from what it was previously? Is it now stronger in the mids, bass or midbass. Does it have the same HF response ... I mean air and extension?
My speakers came with a really fancy SS active crossover. Initially, everything was fed by this including the amps running the midbass arrays and ESLs. Then I figured that running my tube amps directly to the main speakers had to be better. It wasn't ... although more detailed, it was just too thin sounding particularly on vocals and it took a long time to fix. But fix it I did and it's now much easier to pick the difference in component parts. I think a similar thing is happening in your system.
Naz
You make many good points and ask many important questions. I appreciate the concern and wisdom evident in your words.Let me give the condensed version. It will still be too long.
After hearing these speakers (Scott's) we (Steve, Rick and I) felt like what we had were lame toys. They sounded pretty but they had no balls. Yes we heard bass but we didn't feel and experience it like we now knew was possible. In some ways and with some music we liked the sound of what we had better. But the grandeur of what we experienced could not be denied nor discounted. We were ruined you see. Worse yet, the change to a tri amped system and the requirement for bass wattage meant a solid state amp and an active crossover.
So suddenly I found myself in foreign waters and many variables to balance. It has been daunting and I have done my best to make informed decisions. Some, like the choice to use a pro audio active crossover are temporary and born out of needs at hand.
There is a very strong possibility I am about to embark on the circular marathon path. I hear plenty telling me to go passive crossover or at worse, use identical amps and line level passive. I hear the words but I am swayed but what seems to be a technically superior approach. Certainly it is the proven path for any "serious" approach to sound reproduction in areas (outside the home) where cost is not the primary factor.
If a CD player can be a worthy source is it really inconceivable to think that it is possible to "process" the signal and spit out the right hertz all time and phase corrected.... and then be able to pick good drivers with flat impedances within the pass band.....and then for the first time to really have that load line nailed....and accomplish all of this with no degradation of sound and overall superior operating parameters?
Big and ballsy yet detailed and refined, and even delicate when called upon. To get the simple stuff out of the way first let's agree that this simply means you've gotta have a sub (or more, I have 8 X 12" in each side)! This also means big power to drive them. The good part here is that the sub amps don't have to be great and I've proven that (at least to my satisfaction). When I bought my current speakers I actually ran the subs with the pair of Gryphon class A monos which were internally bridged and good for 650 of the best watts SS can provide ... yep just for the subs. Obviously this was more than overkill and didn't make sense long term and eventually I replaced them with, of all things a pair of Class D PA amps which could provide 1500W when bridged and cost less than a grand each. I still have them today and while not quite as good (but damn close for bass use) they are still in my system.I bought the ARC Ref 600s (600W) to drive the combo of my midbass towers (an array of 8 x 7" drivers) and the ESL panels which are crossed over at 180Hz. Today I run them with my Parallel SE 845s good for only about 75W. The big ARC PP amps sounded good and everything was there from highs to lows but they just lacked the depth and realism that SE is capable of and they were fatiguing. Mind you they finished up a whole heap better when converted to triode mode along with some other mods. I've tried all sorts of PP and SE amps in my system and SE wins in almost every way for realism. There are some good PP and SS amps just as there are bad SE tubers. But given the choice, for overall sound its SE for me.
If I was building some speakers on a reasonable budget I think I'd start with 12" subs (15" can be loose but great if you can find good ones). I'd opt for a line array with some decent drivers for the mids as I think these are the most important of the lot. I'm not sure what I'd use on top, I love my ESLs but they can be a bugger to get right and will always only ever be great in the dead centre position ... but in that position WOW! Ribbons maybe or just good fabric tweeters.
With half decent speakers, plenty of power in the bottom and the bottom kept right away from the mids with a steep slope filter ... and a very good source, I'm absolutely convinced that SE will give you the best result. Personally I'd keep the signal path as clean and simple as possible and that means no active crossovers in line with main speakers, only subs. The caveat being that I haven't heard good tube active crossovers.
My 5 cents worth.
Naz
Hi ,
Hmm , have you tried inverting the phase of the comp drivers yet ? Just thought about your 3way to 2 way problems again . I'm sticking with 2 ways for the time being for the sake of my sanity ;) BTW Tads aren't that expensive for what they are , even the blown ones for $200 are worth considering as Radian replacement diaphragms are readily available . The only issue are the horns . Unless dirt cheap TH4001 can be found (never!) , custom types like the Azura 340 or Salad bowls need to be considered due to the non-standard 1 15/16" throat . I suppose you could just slap on a 2" horn though ;) You are right about the larger cone drivers , just by modelling you can see why cubic inches are so important with HE , and why big boxes are needed for really deep bass . I had to compromise due to funds and went for a 10" Seas H368 . Not a bad driver for the money and 93dB sensitive , rolloff needs to occurr well below 1k due to breakup which is the main caveat . I'm using these in 120 litre EBS boxes tuned to Fs , which is as big as can be tolerated . In the same cabinet size and same port I could go for a 15" Usher 15HM in a SBB4 'super boom box' alignment . I have a small listening room so you can only imagine the amount of room gain . SBB4 is probably the best , letting the room reinforce the low registers . Any speakers which are flat all the way down should be avoided IMO . I'm still at the conclusion that the system overall , including room interactions , is what needs to be approached rather than hammering at each 'black box' in turn . It would also be nice to know what I'm doing too but learning is the fun part at the moment :) Amps . PAH ! Easy . Speakers , well , I'm still working on it LOLcheers
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