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I have made single driver full range speakers and love them. But there are compromises and I'd like to explore adding another driver to the system. I plan to bi-amp so that the XO will be in the line stage (active or passive). And I would like to start my explorations with Open Baffle but would be interested in opinions to the contrary.
I see two options,
1) small full range (e.g. 4" size) + woofer (e.g. 15" size) with XO below the 'critical audio range' at around 300Hz
OR
2) large full range (e.g. 8" or larger size) + tweeter with XO above the 'critical audio range' at around 3kHz
What are the pro's and con's of these two options ?
I see two options,
1) small full range (e.g. 4" size) + woofer (e.g. 15" size) with XO below the 'critical audio range' at around 300Hz
OR
2) large full range (e.g. 8" or larger size) + tweeter with XO above the 'critical audio range' at around 3kHz
What are the pro's and con's of these two options ?
In short I think that if you've been moderately happy with FR projects so far (which 4-5" drivers IIRC), you'd likely be more satisfied with the 1st approach. It'd likely be much easier/affordable to find a 12-15" woofer with decent performance into the 500-800Hz range (I think it's always agood idea to have smooth performance at least one or 2 octaves beyond the nominal XO point, regardless of the location /slope of filters), than the other way around.
The major pro of the first option might well be that many builders may already have existing FR drivers quite suitable for wide-band mid/tweeter operation. For example the Fostex FE126E, FF85(W)K, Alpair6P or CHR70.3, Fountek FR88 would be at the top my short list for experimentation - no doubt other models will be suggested.
I've heard few DIY & "commercial" OB systems over the past 5-6 years - Hawthorne Silver Iris coax, MJK inspired with FF85K and Eminence woofer (forget which), Lowther/Tone Tubby, the big PHY coax, and at least 2 or 3 more. While some have sounded great in large rooms, for me the biggest con of any has always been aesthetics of fitting them into either of the real rooms that a system would occupy in my home. Simply put, some folks do not have the option of dedicating the appropriate space required for optimal performance of a full sized OB, dipole panel whether ESL or magneto-dynamic, or un-compromised multi-way front loaded horns - hence the continued popularity of more conventional "boxes".
The major pro of the first option might well be that many builders may already have existing FR drivers quite suitable for wide-band mid/tweeter operation. For example the Fostex FE126E, FF85(W)K, Alpair6P or CHR70.3, Fountek FR88 would be at the top my short list for experimentation - no doubt other models will be suggested.
I've heard few DIY & "commercial" OB systems over the past 5-6 years - Hawthorne Silver Iris coax, MJK inspired with FF85K and Eminence woofer (forget which), Lowther/Tone Tubby, the big PHY coax, and at least 2 or 3 more. While some have sounded great in large rooms, for me the biggest con of any has always been aesthetics of fitting them into either of the real rooms that a system would occupy in my home. Simply put, some folks do not have the option of dedicating the appropriate space required for optimal performance of a full sized OB, dipole panel whether ESL or magneto-dynamic, or un-compromised multi-way front loaded horns - hence the continued popularity of more conventional "boxes".
I think the smaller fullrange + woofer could still be accurately called a "full range" setup, whereas full range + tweeter is pretty much a 2-way. From what I understand, the benefits of full range (coherance, imaging, lack of timing issues, and lack other issues introduced by crossovers) are better preserved in the fullrange + sub scenario rather than fullrange + tweeter scenario. I guess it all depends on the quality of the crossover and the overall design of the system, driver selection, etc. It seems like it would be easier to make a fantastic sounding 4" fullrange system with the bottom end filled in with a (sub)woofer, simply because the bottom end is non-directional for the most part.
Having said that, I am currently toying with the idea of adding tweeters to my fullrangers. Before that I was considering adding a sub. I can't fully commit to either modification because every time I sit down and listen to well-recorded/mastered music, I am just soooo impressed with the sound. I think what often leads me to think about "more bass" or "more air" are substandard recordings. In other words, when I play excellent tracks, my system is lacking nothing. The question for me, then, is do I want to modify my system in some way to make up for poorly recorded or mastered tracks? The second question is; if I do make such additions, how will all the excellent recordings be affected?
The reason I question all of this is because I have only recently transitioned from good quality commercial 2-way bookshelf speakers to a pair of DIY fullrangers and the difference in the listening experience stunned me. With the commercial two-ways, all my music sounded "quite good". With the fullrangers, excellent tracks sound truly excellent (like nothing I have experienced in audio before) but lackluster tracks sound, well, lackluster. This has been a bit of a double-edged sword, which has me leaning toward adding a sub and/or a tweeter at one moment, and then wondering why I would even consider that at another moment.
Are you having a similar experience? I wonder if this is a common pattern for fullrange listeners, and I wonder what others have done to address the issue (other than turning their fullrange setups into multi-ways). Perhaps one solution is to simply avoid poorly recorded/mastered music, which I find myself doing more and more. The trouble with this is that a lot of music is poorly recorded/mastered.
Having said that, I am currently toying with the idea of adding tweeters to my fullrangers. Before that I was considering adding a sub. I can't fully commit to either modification because every time I sit down and listen to well-recorded/mastered music, I am just soooo impressed with the sound. I think what often leads me to think about "more bass" or "more air" are substandard recordings. In other words, when I play excellent tracks, my system is lacking nothing. The question for me, then, is do I want to modify my system in some way to make up for poorly recorded or mastered tracks? The second question is; if I do make such additions, how will all the excellent recordings be affected?
The reason I question all of this is because I have only recently transitioned from good quality commercial 2-way bookshelf speakers to a pair of DIY fullrangers and the difference in the listening experience stunned me. With the commercial two-ways, all my music sounded "quite good". With the fullrangers, excellent tracks sound truly excellent (like nothing I have experienced in audio before) but lackluster tracks sound, well, lackluster. This has been a bit of a double-edged sword, which has me leaning toward adding a sub and/or a tweeter at one moment, and then wondering why I would even consider that at another moment.
Are you having a similar experience? I wonder if this is a common pattern for fullrange listeners, and I wonder what others have done to address the issue (other than turning their fullrange setups into multi-ways). Perhaps one solution is to simply avoid poorly recorded/mastered music, which I find myself doing more and more. The trouble with this is that a lot of music is poorly recorded/mastered.
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cogi:
I'd first try adding woofers with HP on the wide-band mains to provide more dynamic headroom. Depending on the existing electronics there are a few ways to achieve this - passive line level XO are relatively cheap to put together for fixed values, and can even be incorporated as input filters on amp.
I'd first try adding woofers with HP on the wide-band mains to provide more dynamic headroom. Depending on the existing electronics there are a few ways to achieve this - passive line level XO are relatively cheap to put together for fixed values, and can even be incorporated as input filters on amp.
Chris,
Yes, I was looking at some of the pre-built XOs over at Parts-Express a few days ago. It's just that so many fullrange addicts are all about avoiding crossovers at all costs. There must be something to that, no?
Yes, this sounds familiar to me - I was smitten when I heard well recorded music on Fostex FE166EN in BiBs. It was quite unlike any other speaker listening experience before. Been dabbling in FR ever since.
And yes, so much of music is pretty poorly recorded. I am struggling for a solution too, and Full Range ASsisTed with woofers (or sub-woofer) looks like the only way out; that too, probably bi-amped.
-Zia
Make it 7kHz or higher - the critical part, so far as I can tell from Fletcher-Munson etc, ends around 5kHz.
On principle, I'd take the 4" FR + a woofer over a larger FR and a tweeter. The reasoning being that a driver that can shift lots of air (for "proper" bass) won't be able to do the upper midrange as it should be, so the crossover must be in the lower midrange, allowing a smaller driver to do what it does best.
That said, for music reproduction at reasonable levels in even a large room, a pair of the 8" Fostex drivers with supertweeters did rather well, though I'm not sure how they'd cope playing something with lots of really low content.
I'd also say that, while tapped horns (what my current system are built around) are very good at bass, getting them to meet up with a 4" driver puts a lot of stress on the smaller driver, so I'd take a larger, direct-radiating speaker for this application. Oh, and active crossovers.
Chris
For me it's more a case of "less is more" , but there are limitations as to how "-less" you can go in a multi-way. I generally like to avoid XO in the "critical range", and passive speaker level components for XO/filters as much for their cost as sonic penalties - of course any speaker system with drivers operating over different band-widths are de-facto multi-ways, and the determining factor might well be the requirement for multiple channels of amplification (not necessarily an impediment for a DIY addict)
edit - what brother Cal said
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chrisb - yes I've had some good experiences so far with 3" (Fountek) and 4.5" (Fostex, CSS) full range - although I haven't found the right application for my FE127Es - they are sitting unused until I figure out how to deal with their treble peakiness.
Cogitech - I noticed the issue with recording quality when I got my first hi-fi, it's a 2-way floorstander PMC speaker with Byrston amp and YBA CD and Magnum Dynalab tuner. I ended up throwing away half my CD collection and finding only a few FM channels that are up to the challenge. Moving to full range speakers did make the difference more acute. I don't have any vinyl - and perhaps that is something I should change in the future....
Thanks for the replies from everyone - I see a rather clear preference emerging so far and this helps me in thinking about the amplifier design that will be needed (all tube, SE for the full range, PP for the woofer).
Cogitech - I noticed the issue with recording quality when I got my first hi-fi, it's a 2-way floorstander PMC speaker with Byrston amp and YBA CD and Magnum Dynalab tuner. I ended up throwing away half my CD collection and finding only a few FM channels that are up to the challenge. Moving to full range speakers did make the difference more acute. I don't have any vinyl - and perhaps that is something I should change in the future....
Thanks for the replies from everyone - I see a rather clear preference emerging so far and this helps me in thinking about the amplifier design that will be needed (all tube, SE for the full range, PP for the woofer).
Even SS would be ok for the woofer I guess, specially given that it takes more watts to produce LF in a smaller box. There are good options in Class D for cheap.
I'd insist on SS for the woofer. Output transformers give valves higher output impedances, which affects Qes of the speaker, in turn messing up any nicely tuned cabinet you might've designed. The added effective series resistance also adds output around impedance peaks.
Chris
EDIT - that said, I've heard some very pretty sounds from valves. I just feel the design of a speaker to be driven by valves requires more involved design.
Chris
EDIT - that said, I've heard some very pretty sounds from valves. I just feel the design of a speaker to be driven by valves requires more involved design.
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+1, it is usually done with XO only on the tweeter, so the extension of the FR determines the frequency, usually above 10k.
My preference is the FR + Woofer.
Why it has the potential to work better is down to the wavelength at the XO point. One gets rid of a very significant downside of XOs if one can space the drivers such that they are within a 1/4 wavelength (or less) of each other. If one can do this then the drivers are essentially co-incident -- to do the same with a helper tweeter it would need to be co-axial with an appropriate time delay on one driver.
Further, there are LOTs of decent midbasses to choose from that extend to 1kHz+, and a growing number of FRs that will hit 100 Hz or less and have extension to 20k+. This engenders a simple 1st order XO which means retention of time/phase. It is also an ideal place (if one takes care with driver selection) to do a series XO. The very nature of the series XO also means that the responses of the 2 drivers can automatically compensate for anomalies inherent in the drivers. This is one place where a passive XO can have advantages over active XOs.
Third, careful choice of XO frequency (amps & impedances too) can get you inherent BSC (doesn't apply to OBs, MJK has good coverage of that in his passive baffle articla)
Forth, back to the wavelengths... when down low, there are no issues with lobing of the dispersion because, due to 3, driver response is approaching omnidirectional.
And a comment on item 2. As the cost, sophistication and choice of DSP continues to plummet I can see some serious advantages to using a 1st order series XO to get into the ballpark, and then DSP EQ to tidy up the details.
It should be noted that a WAW / FAST is actually closer to a "real" 2-way than a helper tweeter, as the bass driver handles 2-4 octaves (using 80-320 Hz XO point) whereas a helper tweeter is more like a single octave (XO @ 10k) so you get more of the advantage out of job sharing.
dave
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Althou SS (including class D) is the usualy 1st choice for the woofer, it is very possible to make a tube amplified woofer that works very well. To date, out 3.2 w Class A EL84 PP (within its power limitations) has seriously good bass, cleaning the clock of many a SS amp.
And the whole Qes argument has holes you can drive a truck thru... althou not common, with careful design, the Qm of the system can be made to be <1 and then one can start thinking of taking advantage of what current drive brings in terms of dealing with backEMF, compression due to VC heating and not using the impedance of the driver as a voltage to current converter.
dave
pardon the brain-fart question ( i.e. I should know this) - are they treated to any degree? EQ can sometimes help, but I've enough experience with careful treatment to be inclined for a "mechanical" (permanent) fix
That's easy, sell them and buy FX120's.
jeff
well, that'd work too
as to the class of amp for woofers, there will be many opinions and much advice proffered on that subject, don't look for the same degree of consensus as to what type of drivers and XO points to select
consensus on a DIY forum, what was I thinking?
That's easy, sell them and buy FX120's.
jeff
The notch filter I use on my 126s (still a little forward for young ears) was 3uF, 4r7 and 0.3mH, all in parallel, in series with the speaker. Puts a ~4dB notch centered around 7kHz, which is where I found the most noticable bit was.
They're a more relaxed listen now, which suits me nicely.
That said, I can understand why people would prefer the more forward sound.
We should probably get back on topic
Chris
Indeed , it is easier to put together a 3" and a woofer (or two in isobaric like I did ) .
It's design choice , also budget , seeing that there are little FRs for 200$...
The tweeter choice would otherwise look at smaller than 1" domes , I guess..
Tony
per my recollection the FE126E's peaks were even more pronounced and objectionable than FE127E, so exact values of notch filtering might need juggling
I found the new FE126En to be quite better in all regards
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