|2nd April 2002, 02:36 PM||#1|
Join Date: Oct 2001
Location: Sydney, Australia
New Reference Speakers with Full/Wide-Range Driver
Good day to all,
I am just starting to design my next pair of reference speakers. I have been through the many designs and styles, 2 ways, 3 ways, 4 ways, sealed, bass reflex, transmission line, and more, so I have a good idea what I expect and want from a pair of speakers.
My latest and most intriguing experiment has been full-range drivers. I am converted to the concept as flawed as it is, I had just grown tired of listening to crossovers messing up my jazz and vocals. As I have been listening to a lot of acapella music lately, you can always hear a crossover smear somewhere in the vocals. It is just too good to be able to listen to a sax run up the scale and it is smooth as silk or listen to an acapella quartet without the crossover humps or dips.
But(it is always there!) I am finding that the ends of the spectrum just put to much pressure on any single driver that I have heard, you give up good deep bass, and find the highs can be just a little too gritty for my ears.
So to remedy that, here is what I am proposing to do.
A woofer in a transmission line with a full/wide-range driver as the mid-range covering from 90Hz+- to 4,000 - 6,000Hz area where a tweeter or super tweeter will take over. Essentially a three way.
Lets look at each driver and what we want from it and why.
The woofer could be a 10" or 12" Peerless or Scan-speak, with a folded transmission line tuned to a bass cutoff of 30Hz or preferably less. I do not want tubby, fat, or boomy bass, I want clean, quick, fast bass, I will using this for music only. It would need to carry the bass up to around 90Hz and I want to use as simple of a crossover as possible, preferably first order.
The mid range - I want the full vocal range completely free of cross-overs, hence the low 90Hz, I have sang with good bass singers that can smash a C two octaves below middle C, which is only 65Hz, not many but a few. most of the vocal range is from A3 - 87Hz through C6 - 1,050Hz, with a select few sopranos shattering glass a few notes above that. A piano tops out at about 4,200Hz or so, above that you have mostly second harmonics happening. So by covering the 90Hz though 4,000Hz with one driver we completely eliminate all crossovers in the critical hearing, vocal and fundamental range of most instruments. I am completely annoyed with beaming that goes with most larger wide-range drivers, the largest driver I would want would be 4" preferably less. So here is my shortlist of drivers, the Jordan JX92S, Bandor 50AFSW/8, which are fine except are not very efficient. I am open to any suggestions you may have on suitable drivers. I would go for a Manger, but that is such a quick driver that mating a suitable woofer is almost impossible I am told. Again I want to keep crossover as simple as possible, and if possible use enclosure construction to work as passive crossovers. With the two above drivers, a high pass filter is unnecessary because of the roll-off of the drivers. Most likely a low-pass would be unncessary also because we could just tweak the high-pass on the tweeter to pick-up where the mid-range is starting to tire.
Tweeter - 4,000-6,000Hz and above . I have not given much thought to a driver here and would love to hear you recommendations, again remember I have no love for beaming or narrow sweet spots, I prefer a wide, full listening area. So I am assuming a 3/4" tweeter or maybe even a ribbon would be what we need.
I am hoping for a passive cross-over consisting of a first-order low-pass for the woofer, and a first-order high-pass for the tweeter. I may decide to pinch off the top of the midrange just to avoid too much glare and muddiness because of expecting to much of the mid-range in complex and difficult passges. Plus some possible pads to bring everything into line.
OK, fellow full-range junkies, let's hear your ideas and criticisms. I know there are some very experienced full/wide-range listeners in this forum including Planet10 aka Dave(with some very interesting driver ideas), Dice45 aka Bernhard, Mohan Varkey, just to name a few. A budget is not really an issue here, except like everyone, I am always interested in spending less instead of more.
Surf, Sun & Sound
|2nd April 2002, 05:44 PM||#2|
Wizard of Kelts
You mentioned that you want as simple a crossover as possible. For the lower woofer, have you considered a Dayton 10" Mk II or Shiva? I know that neither one is a Scan Speak or Peerless, but both seem to roll off naturally right around 90 Hz. The Shiva says it is "an artifact" of the near field measurement technique, but whatever. On the Dayton, anyway, I would think you could put your inductor to take effect around 200 Hz or so, and just use the woofer's natural rolloff at the 90 Hz crossover point. Hopefully, this will eliminate various phase distortions in the crossover area. By the time various phase effects due to the inductor take place, the woofer is out of the playing range.
I believe that other Adire products have a similar characteristic.
I include a graph of the Dayton 10" Mark II frequency response.
Just a suggestion. Good luck.
|2nd April 2002, 05:54 PM||#3|
Join Date: Feb 2002
Location: Perth, Australia.
Hiya Lynn (Welsh name, from Sydney), maybe some of my experience can help you.
Transmission line bass - I have a pair (of course) of old KEF transmission line cabinets.(flat, oval woofers).
On sine wave type bass they give the biggest, horniest, trouser flappingest, like live sound type bass you could want, but they don't do kick drum quite the same.
For sharp bass attack you need sealed cabinets, and for that ever so slightly undersized volume, I reckon.
Full range mids - 10+ years ago I had a pair of Yamaha NS-20 8"/1" 40wrms/80wmusic rated cabinets.
These are the big brother to the notorious NS-10 pro-audio mixdown mini monitors. 6.5"/1".
Within about zero minutes of listening after aquiring them I decided that I couldn't stand the sound of the crossovers and promptly transferred them to the bits box.
With the aid of a standard signal generator (a PC sound card output would probably be fine), a standard amplifier, 5W resistor and audio signal meter, I impedence equalised each mounted driver to past 45 KHz.
The impedence compensated woofer was connected full range, and sounded nice out to past 8 KHz or so, and the impedence compensated tweeter was bled in on 1.1 microfarad or so.
Tweeter - you must impedence compensate to have a chance of decent sweet and high highs, and all crossover caps need to be bypassed with smaller values to make it work.
BIG Hint 1.1mF = 1.111..... = 1.0+0.1+0.01+0.001+0.0001........ down to tubular types !. Ditto, all crossover capacitors.
With 120W+120W, with closed windows and doors and wardrobes this combo gave huge and immediate lows, and on the right bass lines this system resonated bigtime the walkway railings on a block of 6 apartments. (only on sundays when the neighbours were out ), and the highs went past my hearing range, really detailed and absoloutely no ear bleeding.
This connection gave excellent phase linearity, which gives wonderfull depth imaging - I had sounds coming through from behind the far curtains, and from behind me ! (and friends).
And this gives fantastic reality to vocals - the lead singer is between the cabinets, the drummer talks from behind the curtains and the crowd is around you - no bulldust, but this requires very fine electrical tuning.
IMO series low pass for the woofer roots the attack, or at least roots the HF/LF integration of such a two-way.
I totally agree that the vocals have to be good, and this worked great for me ! (and friends).
An additional paralleled 10/12/15" deep lows cavity if tuned mechanically and electrically correctly ought to sing right and fling rejected energy to the 5/6.5/8 " LMH driver if you you have a near zero inductance parallel connections between the LL & LMH drivers.
If you need more info, just ask.
Remember the fun is in the chase, and in the eating.
BTW - This excellent depth imaging/excellent phase linearity = excellent absoloute polarity revealling = PITA.
Every second track/record/cd will show absoloute polarity reversals and correct AP is correct AP - you will have to do a lot of swapping of the polarity of the speaker wires at the amp as required !.
IME - I'm all for as full range as can be - with carefull electrical tuning and carefull LL and HH augmentation it can go loud, clean, real, and fast.
Multiple drivers (D'Apillito) can be good too ...... understand two woofers are more than twice as good as one, because of nearfield coupling. Also witness a guitar stage quad box for efficiency .
|2nd April 2002, 09:34 PM||#4|
Join Date: Sep 2001
Location: Sth. Oz
This is a brilliant concept and if you use the right components can be easily designed by ear alone provided you use the right driver for the midband with known response at the extremes. In essence this can be classed as a full range system with a sub below 100Hz and a super tweeter above 10k. I say 10k because the 4-6kHz figure is still far too close to the ears most sensitive region which if you look at a fletcher munson curve will show you what I mean. That is, if you want to avoid the pitfalls you were talking about. The dayton 10" looks like a good canditate since the response could be rolled off with a simple inductor but i would'nt rule out the Peerless CSX 257 H either, you can buy them from WES Comps in Sydney for about AU$100 ea. For the mid I would suggest the Vifa 4" fullrange unit currently on offer over at Parts Express. This unit has a white cone and a response from 100Hz to 10kHz. Check it out. Then all you need is a tweeter for the range above 10k. You could use an old stalwart, the Vifa 25mm alloy dome which has been around for a while and unusually good sounding for the price @ AU$75 from Jaycar.
Make what you will of this, but above all have fun and enjoy the music...
|2nd April 2002, 11:38 PM||#5|
Join Date: Oct 2001
Location: Sydney, Australia
Thanks for the input. Keep it coming. I am open to all comers and all criticism.
Some great ideas here, but unfortunately, I do not have time for a detailed response at the moment. I just sneaked a quick look at what everyone had to say before heading to work.
So I will be rolling this around in my pea-brain all day while I am at work and hopefully get enough done that I won't be sacked!
Thank you everyone for your comments. Will give a detailed reply soon. Must run, see you after work!!!!
Surf, Sun & Sound aka Lynn
|2nd April 2002, 11:56 PM||#6|
Join Date: Dec 2001
Location: VA, USA
So by covering the 90Hz though 4,000Hz with one driver we completely eliminate all crossovers in the critical hearing, vocal and fundamental range of most instruments. I am completely annoyed with beaming that goes with most larger wide-range drivers,
I incorporate that technique into my projects. It works well. I will not crossover lower than 3.5k, preferably 4Khz or over. Though THEIR IS signficant audio information still in this range, I find it to be of minimal consequence. Also remember that IM distortion rises significantly when trying to cover too wide of a range with a single transducer.
I do find that their are some drivers that are suited for that range that are not so small as you seek. A 4" driver will have to be crossed signifcantly higher than 90 Hz. You can use a few 5" units that low, but will then have to use a ported enclosure tuned close to that range which IMO compromises that frequency range. Realisticly, you will need to cross with a steep slope at 150-175 with any 4" driver, while allowing for acceptable output levels. I do not see any way to use a driver 5" or smaller under 100 Hz, with excellent results. You will deal with either non linear distortions or poor transient performance.
Focal makes a very coherent W cone woofer and an Audiom midrgane, 6.5" and 7" respectively, thatoffer outstanding off axis performance a little over 4 Khz. Suprisingly, many of the 'full range' drivers have poor off axis response over 3 Khz, even though on axis in flat to around 20 Khz. Pay attention to this little fact when viewing their data sheets.This will result in poor power response, very undesirable IMHO as this will seriously damage imaging.
The Manger is an excellent idea too, as an extended midragne, but I fear you would need to match it with infinite baffle or dipole woofer in order to reasonably integrate with it's excellent transient decay characteristics, both expensive options if you wish to have reasonable SPL levels. A TL is another possible option. I have considered this driver, but the price alone for raw drivers detracts me from it. Maybe if they could produce a $300 model I would bite.
As for tweeters, consider the Raven, Hi Vi, Phillips, BG, Linaeum or any other ribbons orribbonhybrids. Of course, I never cared very much for any dome tweeter, so perhaps I am biased in this respect.
Have fun, and regardless of what you do, please post your project here when it is completed so that we will have something to read. :-)
|3rd April 2002, 03:46 PM||#7|
Join Date: Oct 2001
Location: Sydney, Australia
A thoughtful Reply
Has it been a long day or what!! I have finally had time to sit down(11:00PM) and digest this information and formulate a response. So I will tackle each post in turn and then have some general thoughts.
To the Kelticwizard,
Excellent idea, to use a sub woofer that will have a natural roll-off right where we want it around 90Hz. The only reason I suggested the Scan-Speak or Peerless was because of the ease of availablilty. I know where I can get the Shiva here in Australia, but am unsure of the Daytona. Anyone with details please let me know. What are your thoughts on the transmission line versus a sealed box in regard to Eric's comments.
Can we get the same roll-off effect with the Shiva or a Peerless or Scan-Speak 10" or 12" as you have shown with the Daytona?
I need more information, so I am asking!!!
I must confess, you have struck whole new territory for me. I read a similar rant by you in another previously posted thread with very keen interest, but chose not to reveal my ignorance till now. Possibly, what you have uncovered here is what I find irritating about most cross-overs. After more thought about the sound I want to achieve, I have concluded it is not about a few db dip or humps caused by cross-overs, although they can be very annoying, but rather there is some sort of smear, harshness, or jumpiness that I do not like that seems to go with most cross-overs, so it may phase distortions or polarity or whatever. So lets hear more on this subject.
You have hit the nail dead center on the head. I agree that the mid-range driver is the critcal piece of hardware here. I want to voice the system by ear, so it will be an interesting and challenging project. I will check out the 4" Vifa as a possible mid-range. If you have any other suggestion, I would be happy to hear them
It is good to hear from someone who used this idea before. I am quite aware of the deterioration of a lot of full-range drivers off axis, that is why I am going to try and use as small of driver as possible. One of the real tests on a speaker is to play an acapella quartet with a strong and deep bass singer, if there is any problems you will start getting bass smear. There is a half-step difference between C2 and C2#, and you should be able to hear it, clearly and cleanly. That is why I am trying to push the midrange into the 90Hz and would ideally like to go as low as the mid-60Hz's, but that is asking to much and still have a small driver to avoid beaming at higher frequencies. I am willing to give a few 1000HZ at the top to get a lower end. I would love to use a Manger but they are just too pricey and I have not heard a good woofer that was intergrated yet.
I have read Lynn Olson's papers on his ideaology on the design of the Arial, and feel much the same way about this project. I am interested in a unique and particular sound. If I wanted a three-way, there are plenty of kits and projects out there where all the grunt has been done. Please, I am in no way near as experienced or as qualified as Lynn Olson(we do share the same first name, may help!), but I like him, do not want an ordinary three-way(or two-way in the case of the Arial). So I know we are going to need to push the envelope here a bit.
The choice of the mid-range is the most important here, and I do not want to have any crossover, mechanical or electrical, above 100Hz. This driver must be able to handle from at least 90Hz to up around 6000Hz and minimize beaming. If I need to I would consider using multiples in parallel or series. My choice is still a Jordan JX92S with concerns of off-axis high frequency roll-off due to the size, the Bandor 50AFSW/8 is almost perfect if they run close their published specs( http://www.bandor.co.uk/Bandor50R.htm - scroll down for this model), with the Bandor 100, and a new addition of the Vifa 4", as serious contenders. The Vifa 4" looks very good as bottom roll-off would down 3db at around 90Hz and has the advantage of being around $40AU per driver versus $250AU, thus very conducive to using multiples. I am sure there other driver options out there. I have being hearing about a Tag-band? El cheapo I know. I do not have to spend $250AU per driver but will if I need too. So keep the driver options coming in. I would be especially interested in hearing from Planet10 aka Dave on this subject. I want to make a decision on the mid-range driver first and work from there.
Gentlemen, I hope this reply makes sense, it is after midnight here and my brain is on the way out. Thank you for you input so far. I will be back with more.
Surf, Sun & Sound aka Lynn
|3rd April 2002, 05:31 PM||#8|
Join Date: Apr 2001
Location: Moonee Ponds, Vic, Australia
I use 4 of the Bandor 50mm driver per channel in sealed 6+ litre enclosures, I have had them for 10 years (The Aust$ was about 55UKpence at the time I think, not these days ) so mine are earlier versions with Copper voicecoil wire and a little more mass.
I run them full range no woofers or tweeters, the bass in my room is amazing, when the system is going I don't think of getting a sub woofer, but when it not , like now as I am replastering/soundproofing the room, I see those little drivers and wonder what the Bandor 300mm unit is capable of.
They are more revealig than my (old) Stax SR Gamma-Pro with transformer energizer, but with out the slight rise in the high end the staxs have, they image really well, room filling wall to wall sound.
I think luck played a big part in my room, being smallish, 4.3lx 3.7Wx3.07H, the modes must suit these speaker very well, also being DC coupled from CD player to speaker can't hurt.
Adding a woofer to a system thats working well is a daunting task, I'd think just the presence of large enclosue/s can adversly effect the room sound, and I would prefer a sealed woofer.
|3rd April 2002, 05:50 PM||#9|
Join Date: Jan 2002
Fostex FE108 Sigma
What about the Fostex 108? It's used by lots of people for many years and has a good reputation as far as I can tell, never having used them myself. Specs <a href="http://www.fostex.co.jp/int/pages/products/spunits/unitpdf/fe108sigma.pdf">here</a> and it looks like its got a good dispersion up to over 5kHz. Bass might be slightly more of an issue, but a TL/labrynth like the Ariel would extend it clean below what you want, and it might even do it in a stuffed sealed sub-enclosure of sufficient volume. Or you could try a semi-open baffle like the big ProAcs. Multiple drivers being crossed to a tweet at 6k will give rise to some possible comb-filtering problems due to the spacing of the drivers being longer than a wavelength at that frequency. I used a cheaper Fostex 4" driver years ago in a line array (9 or 16/side) and there was a lower treble/upper mid anaomaly that we could never quite cure, which was not present with a single driver on an open baffle. I put this down to combing.
For a tweet to match, make sure that the mid and the tweet have approximately the same dispersion pattern around the crossover frequency as this will help them integrate sonically more seamlessly in a real room. Suggestions would be some of the Fostex horns like a T90A/T925A (even an FT17H!) or a Fane ST5022.
For bass, I like the SEAS CA25FEY (DD H317) 10", in an isobarik "clamshell" type arrangement such as Wilson Benesch use. Chris Brady has a DIY TL version <a href="http://www.teresaudio.com/haven/">here</a>, click <b>subwoofers</b>.
|3rd April 2002, 06:22 PM||#10|
Join Date: Jan 2002
I suggest the Karlson speaker enclosure
I have used this enclosure with an EV 12TRXB for decades and it is my favorite:
Unfortunately, the 12TRXB is no longer made but they show up occasionally on ebay. Other speakers will also work as noted in the above site.
For more info go to google and srearch on Karlson speaker.
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