I was just over at the Multi-Way speaker forum. I enjoy visiting. There were discussions on optimizing slotted cabs that’s very interesting to me and applicable to full/wide range drivers. But then I read about problems using soft dome mids, crossover optimization related issues, choosing caps and coils and frequency points to crossover… I felt bad. It’s so much easier and less audibly obtrusive crossing above 10k and below 200hz… if they only knew!
One thing that troubles me, and maybe someone can elaborate, is why so many have set ‘rules’ on how high in frequency specific diameter drivers can operate up to effectively… for example, a 12” can only be used up to 1,200hz, an 8” up to 2,000hz, etc… is it all about dispersion?
One thing that troubles me, and maybe someone can elaborate, is why so many have set ‘rules’ on how high in frequency specific diameter drivers can operate up to effectively… for example, a 12” can only be used up to 1,200hz, an 8” up to 2,000hz, etc… is it all about dispersion?
I think so, mostly. Beaming. And then there is cone break-up that tends to happen around the same point for similar size drivers.
I have a pair of Tang-Band 6.5" woofers that will play right up to 12Khz. They beam badly that high, tho.
I have a pair of Tang-Band 6.5" woofers that will play right up to 12Khz. They beam badly that high, tho.
Thanks Pano! But why obsess over beaming and break up modes when adding additional drivers potentially damages the sound further? I don’t enjoy debating driver limitations with individuals pointing to spec sheets when I know (and they don’t) larger diameter drivers sound good at higher frequencies. Why are we hearing ‘good highs’ with larger diameter drivers despite these limitations?
Nobody beats the WIZ! Whizzer cones help with dispersion but I don't know if you can get aftermarket cones for speakers that were not designed with them in mind. Phase plugs are another option. Dave at Planet10 HiFi sells both finished plugs and blanks so you can make yours to size.
If you want to add a phase plug, the Planet 10's are well regarded and Dave is knowledgeable, helpful and makes regular posts on DIYAudio. I do have to say, though, that I have never used them.
If you want to add a phase plug, the Planet 10's are well regarded and Dave is knowledgeable, helpful and makes regular posts on DIYAudio. I do have to say, though, that I have never used them.
Many of those dispersion arguments are based on theorectical data generated by simulating a flat rigid piston. This proves true with real drivers but the limits are much more fluid. Things get even more fluid if you abandon the idea that the ideal driver is rigid within its passband.
In a multiway the issue isn't the dispersion per sey, but the change at the crossover as you pass from a large driver that is starting to have limited dispersion to a smaller one that has wide dispersion. (ie off axis FR becomes undulating)
With a FR driver there may not be as high a level of dispersion at the top end, but there are no discontinuities with off-axis dispersion.
Most FR drivers also pay little head to the rigid piston idea, by introducing controlled flex the effective size of the driver can become smaller as frequency rises. This is a much greater engineering challenge than brute forcing a rigid piston. If this shrinking diameter can be done without a whizzer i think, in general, that is a good thing. Whizzers introduce a whole set of other issues. One of the reasons i tend to prefer 3-5" FRs. Bass is best served with dedicated woofers if you need a true FR system -- and you can XO down where the drivers are becoming essentially omni-directional avoiding the whole dispersion and interdriver issues inherent in XO discussions.
dave
dave
In a multiway the issue isn't the dispersion per sey, but the change at the crossover as you pass from a large driver that is starting to have limited dispersion to a smaller one that has wide dispersion. (ie off axis FR becomes undulating)
With a FR driver there may not be as high a level of dispersion at the top end, but there are no discontinuities with off-axis dispersion.
Most FR drivers also pay little head to the rigid piston idea, by introducing controlled flex the effective size of the driver can become smaller as frequency rises. This is a much greater engineering challenge than brute forcing a rigid piston. If this shrinking diameter can be done without a whizzer i think, in general, that is a good thing. Whizzers introduce a whole set of other issues. One of the reasons i tend to prefer 3-5" FRs. Bass is best served with dedicated woofers if you need a true FR system -- and you can XO down where the drivers are becoming essentially omni-directional avoiding the whole dispersion and interdriver issues inherent in XO discussions.
dave
dave
Full range is great for 1 person doing some serious listening. It beams straight ahead and doesn't interact with the room boundries. You can adjust the high end by aiming the speakers on axis or slightly off axis. Now desperison is needed and wonderful if your using the system for home thearter or general listening. It's a person taste, room requirements, decor, cost, and experience with high end set-up. It's a journey we all have to travel. A young person is impressed with loud boomy bass. An old person is looking for something more accurate/real. In the end you assemble what is right for you and don't pay attention to hype.
Your generalizations are far to general. True in some cases, not in others.
dave
As a multi-way addict, my reasoning is simple. I like proper bottom end, not something that gets very vague below about 100Hz, clean, undistorted treble, not some mess of cone breakup and resonances pretending, and a good, flat overall frequency response. If you can find me a single driver that does that then I might be converted. 
😀
😀I suppose some of the rules are based on some type of acoustic physics. A typical 8" cone is probably starting to beam at around 1kHz or so and depending on the cone material, break-up is inevitable, so high end response is the sound of distortion. Break -up can be mitigated to some degree by damping the cone, but this can also lead to the deadening of the sound.
I think the rules follow that speakers with wide uniform power responses can sound pretty darn good with less distortion.
Single driver speakers are about purity, cohesiveness and simplicity. If the listener values these qualities over others then this is the gospel they follow. Adding additional drivers tends to lead to crossovers, complications and dilution of the above qualities. The solution is to have more than one speaker.
Having said the above my preference is for the 4" paper, unadulterated single driver speaker. I have found that this size is the best compromise between highs and lows and ultimate volume level, while keeping that cohesive presentation. No filtering allows the driver to directly couple to the amp, which seems to preserve the immediacy/aliveness of the music. If more spls are needed and/or more people are listening, I simply change the speaker.
As a multi-way addict, my reasoning is simple. I like proper bottom end, not something that gets very vague below about 100Hz, clean, undistorted treble, not some mess of cone breakup and resonances pretending, and a good, flat overall frequency response. If you can find me a single driver that does that then I might be converted.
Well, my very first experience in DIY audio has me convinced that there are full range drivers that can offer just what you have described. The drivers are the CSS EL70. They have an Fs of 64hz, which in the right cabinet design can produce very tight, defined bass down into the low 40s, and plenty of it. The overall frequency response is not perfectly flat, but it can be EQed very easily to be so. Dial them down a bit around 440hz and up a bit between 14k and 20k and Bob's your uncle.
Based on this, I can only imagine what might be possible with some of the so-called "high end" FR drivers out there.
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As a young person, I'm not sure this is true. Most young people have never heard a decent system, so when a car pulls up playing actual bass (as opposed to the pretend bass that comes out of miniture iPod docks), they think that's what things are meant to sound like, so that's what they persue.
Back more on topic, if you've ever heard a speaker with an uneven power response in an acoustically live room, you'd understand why people persue decent off-axis performance. It just sounds odd - some frequencies are reflected back more than others, giving a very strange stereo image.
Chris
Amen. As new as I am to DIY, I have been a music lover and been listening to all sorts of loudspeakers my entire life. This is my first experience with an FR speaker system and I cannot believe how fantastic they sound.
Indeed, which is why I do my EQing in DSP; as many others have already discovered, this works incredibly well with FRs.
The design I selected ("Castle" microTower) overcomes these issues quite well, I think. The extra top-firing driver provides plenty of dispersion without losing coherence with the front-firing driver. The two drivers are identical, and are 4ohms each, so it is simple to run them in series for an 8ohm load. The cabinet can then pull the bass from both drivers (which is why I think this design produces such wonderful bass for it's size) and also the result is a 40 watt loudspeaker that can easily produce enough music for many listeners. My house full of guests at Thanksgiving could all certainly enjoy the music equally 🙂
One attribute of a single Full Range speaker is imaging. It's the best I've ever heard. I've listened to a lot of different speakers and none could present space and time like it. That made up for the inequalities FR have. I still feel only 1 person at a time can listen seriously, similiar to near field listening. Anyway, my 2 cents......
cogitech - as your current (avatar) photo suggests, yes these silly little boxes can rather give you pause to look both ways for the rest of the system - I built my (the?) first pair of these about 18months ago, and never cease to smile when listening to them
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As a multi-way addict, my reasoning is simple. I like proper bottom end, not something that gets very vague below about 100Hz, clean, undistorted treble, not some mess of cone breakup and resonances pretending, and a good, flat overall frequency response. If you can find me a single driver that does that then I might be converted.
So, why does that mean you need a multiway? FRs have gotten better in the last few years, what was the last FR you seriously listened to?
To add serious dynamics a FAST is suggested. My last was good from 30ish to 30k
dave
BLH Lowthers about three years ago. Nasty.
Which is, by the nature of having two drivers, a multi-way system. 😉
🙂 I really lucked into my avatar. I am new to Kamloops and I happened to see this sign on the way to pick up the kids from school the other day. I had to do a double-take before I could believe it, as I had just finished the last coat of satin on my towers and re-installed the drivers a couple hours earlier. Driving along with a smile on my face about the success of my first project, and bam! I see this sign. 😱 I just had to stop and take a cell phone pic.
Really sorry for all the off-topic, OP, although I think others have basically answered your question about the size limits, beaming, etc. I have only used 4" FRs, so I have nothing to say on the matter except that I love them 🙂
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You would not be alone. I had a room at the Montreal show a few years back where we had only FR drivers. 4.5, 6.5 and 8 inch. The 8 was my fave for its weight and tonal balance, but the visitors to the room really loved the 4.5. It was the big hit of the show for us.
But don't listen to me. I run a system with the crossover right at 600Hz, big fat drivers. So I really don't belong here. 😛
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