In that case the two 32mm coils will still have more surface area! Assuming everything is the same/apples to apples as you say.
Honestly though I don't think you can say what's better without knowing what the budget is, how flexible he is on enclosure size, what sort of extension he wants etc. For a given set of parameters it could go one way or the other depending on what's available.
Thanks for your advices gentlemen.
I realise that my education is limited as many technical subjects are obscure te me. I have just built the Halcyon and I find it has many qualities. Very happy with the results. For me it is perfect for «electric» music as the bass is very present and in front of the mids and highs.
I have a pait of Harbeth C7ES3, they are very «non fatiguing / soft» but lack precise imaging.
For the next project I aim to make a very precise set of loudspeakers, more precise than the Alpair 10.3 and more precise woofers too. My room is 500 sq ft and I listen under 90 db.
I am tempted by one pair of 10 inch woofers as I never had this kind of woofers.
Troels designs seem to be top notch and priced accordingly.
I realise that my education is limited as many technical subjects are obscure te me. I have just built the Halcyon and I find it has many qualities. Very happy with the results. For me it is perfect for «electric» music as the bass is very present and in front of the mids and highs.
I have a pait of Harbeth C7ES3, they are very «non fatiguing / soft» but lack precise imaging.
For the next project I aim to make a very precise set of loudspeakers, more precise than the Alpair 10.3 and more precise woofers too. My room is 500 sq ft and I listen under 90 db.
I am tempted by one pair of 10 inch woofers as I never had this kind of woofers.
Troels designs seem to be top notch and priced accordingly.
Efficiency varies directly with cone size and two drivers only sucks more power and creates impedance issues. One 12 is about the same cone area as two 8's and may give you some actual bass. Using 8" woofers makes sense if you are making a 2-way system because a 12 will start to break up at a lower frequency, and you can add a sub to handle deep bass. If you "do-the math", multiple identical drivers is not the likely choice.
Here another example of using multiple drivers to achieve higher sensitivity (92dB/2.83V 4 ohm stable), in room response to 20Hz, in a cabinet ~100L. And vertical directivity control:
It uses four 7” midwoofers:
Reference:
https://www.audioholics.com/tower-speaker-reviews/perlisten-s7t/#toc-h2-3
It uses four 7” midwoofers:
Reference:
https://www.audioholics.com/tower-speaker-reviews/perlisten-s7t/#toc-h2-3
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Two 8” beats a 10”
Two 7” beats a 8”.
So four 7” beats a 10”
Here’s how the WWtTtWW array is done:
Reference:
https://www.erinsaudiocorner.com/loudspeakers/perlisten_s4b/
Two 7” beats a 8”.
So four 7” beats a 10”
Here’s how the WWtTtWW array is done:
Reference:
https://www.erinsaudiocorner.com/loudspeakers/perlisten_s4b/
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There are none amplifiers that have an issue if the impedance is 4 instead of 8 Ohm. Instead, you are usually profit from the amp delivering double the power.
If "you do-the-math", you'll realize you are usually gain more output from multiple drivers instead of just one. So, having the most drivers an impedance of 8 Ohm, multiple drivers are the most logical and likely choice, especially since most amplifiers are able to deliver a much higher power at 4 Ohm instead of 8 Ohm.
No, Troels designs are lacking spatial data. Speakers radiate in 3 dimensions but Troels and others (eg zaph) just publish the on axis frequency response. That's just a tiny fraction of the sound radiated by the speaker and is not sufficient to decide if it's good or not. It's like trying to decide if someone is attractive while looking at their backside only - maybe you see something you like but there is not enough information to make a judgement.
Likewise, using expensive parts to build a diy speaker without good engineering will probably not produce a good speaker. This is the case with the watt/puppy - fancy parts, questionable engineering and suppar results. Just because it was on the cover of stereophile 20 times and some reviewer said he sold his kidney on the dark web to buy it doesn't mean it's good.
You said you want articulate bass. The problem with bass is the frequency response of the bass is just as dependent on the room as the speaker itself. So maybe you read the Loudspeaker cookbook and decided you need a sealed box with a QTC of 0.707 to have tight bass. Trouble is the room is like a funhouse mirror that can turn that tight bass into a tubby mess. To fix this you need to correct the bass with a DSP such as miniDSP(you will also need a cheap mic and REW). The DSP will also allow you to shape the bass however you want, provided the subs have enough horsepower.
Just make sure whatever sub you build gets down to -10db at 30 hertz and has plenty of reserve power for the DSP correction. You could do 4x Peerless 830668 in sealed box about 2 cubic feet per side (1cf per speaker). That would give you a QTC of 1, -10db at 30Hz and 94db at 2.83V. I built a 3 way prototype based on this woofer and the bass is wonderful, plus there's no need spend a stupid amount of time building multiple vented test boxes, trying to figure out the box losses and tuning the port, etc.
On top of that box you could put a couple of these: https://www.mtg-designs.com/diy-speaker-plans/vbs-6-2 . Not the high end parts you were imagining, but this guy knows what he's doing. If you did a double blind test I guarantee you would pick the MTG speaker over a WATT/PUPPY or a Troels any day, provided it was properly integrated into a good sub. (note, I wouldn't build a lot of the other designs on the MTG site because many were created before he knew what he was doing. I also wouldn't build the subs because they're not tuned).
I'm done ranting, hope you find this helpful.
Yes, agreed completely and I still didn’t read about requirements on LF cutoff, while at sub-90dB you don’t need more than a well-designed 8” system to get down to 35-40Hz.
I agree that neither the watt-puppy or TG's designs are top-notch in a technical sense and that the room rather than the woofers in the mains largely determines low frequency sound quality but some qualification may be wise.
A pair of woofers in one cabinet and the mid and tweeter in another is a good configuration because the optimum design for each cabinet is quite different and isolating them from each other beneficial. A 7" midrange with a pair of 8" woofers and 1" tweeter is not a good choice because the midrange will be resonant and have too narrow a radiation pattern crossing to the tweeter. A 5" midrange is a more appropriate in this respect without surrendering much at the lower end. A waveguide on the tweeter would also help.
TG is a subjectivist rather than an objectivist and this is reflected in his designs. If you value objective performance then most of his designs with perhaps the odd exception are not going to provide good value. Also his way of designing speakers is not wholly aligned with what an engineer would do but not to the extent the designs are poor just not well optimised with respect to technical performance. Unlike some DIY designs his designs are decent just not top notch unless you are subjectivists with a value system that is well aligned with TGs and then some of them might be.
DSP correction applied to the main speakers can significantly improve perceived sound quality at the listening position but it cannot on it's own deliver high sound quality. That requires the room response to be controlled by absorbing low frequency sound and filling in the cancellation dips that DSP cannot correct. The practical way to do this as someone mentioned earlier is with a set of DSP controlled subs distributed around the room and setup to deliver an even and dry/tight response at the listening position. If you use 4-8 they don't need to be particularly large for music, perhaps 8", but if you want thunderous exploding planets when watching films then 10-12" might be a better choice. They don't need to be the same size so a 15" or two with the rest 8" might work well.
A pair of woofers in one cabinet and the mid and tweeter in another is a good configuration because the optimum design for each cabinet is quite different and isolating them from each other beneficial. A 7" midrange with a pair of 8" woofers and 1" tweeter is not a good choice because the midrange will be resonant and have too narrow a radiation pattern crossing to the tweeter. A 5" midrange is a more appropriate in this respect without surrendering much at the lower end. A waveguide on the tweeter would also help.
TG is a subjectivist rather than an objectivist and this is reflected in his designs. If you value objective performance then most of his designs with perhaps the odd exception are not going to provide good value. Also his way of designing speakers is not wholly aligned with what an engineer would do but not to the extent the designs are poor just not well optimised with respect to technical performance. Unlike some DIY designs his designs are decent just not top notch unless you are subjectivists with a value system that is well aligned with TGs and then some of them might be.
DSP correction applied to the main speakers can significantly improve perceived sound quality at the listening position but it cannot on it's own deliver high sound quality. That requires the room response to be controlled by absorbing low frequency sound and filling in the cancellation dips that DSP cannot correct. The practical way to do this as someone mentioned earlier is with a set of DSP controlled subs distributed around the room and setup to deliver an even and dry/tight response at the listening position. If you use 4-8 they don't need to be particularly large for music, perhaps 8", but if you want thunderous exploding planets when watching films then 10-12" might be a better choice. They don't need to be the same size so a 15" or two with the rest 8" might work well.
I'm with @pulexirritans
But if one is going to insist on passive, here's another supporting example, using the same woofer suggested, but in a BR enclosure- 2 cu ft for a single 10"-
Observe the basic bass sensitivity- ~85dB/2.83V/m @ 100Hz. Note that F3/F6/F10 are the 2pi stats, see the cursor for the anechoic F10.
If we wind up the volts to exploit the maximum the excursion AND power handling, here's the maximum SPL and group delay and air velocity through the vent:
Now, let's compare and contrast to a pair of 8" from the same family- the 830667. Same sized enclosure. Mild change to the vent tuning (see next graph) but note the sensitivity difference- almost 5dB!
Now doesn't the impedance drop too low? Still within 4 ohm load (as expected- see cursor).
And what about the maximum SPL- an extra 3dB!
So 5dB high voltage sensitivity and 3dB higher maximum SPL in the same sized cabinet.
What's the catch?
Sorry about your wallet.
But if one is going to insist on passive, here's another supporting example, using the same woofer suggested, but in a BR enclosure- 2 cu ft for a single 10"-
Observe the basic bass sensitivity- ~85dB/2.83V/m @ 100Hz. Note that F3/F6/F10 are the 2pi stats, see the cursor for the anechoic F10.
If we wind up the volts to exploit the maximum the excursion AND power handling, here's the maximum SPL and group delay and air velocity through the vent:
Now, let's compare and contrast to a pair of 8" from the same family- the 830667. Same sized enclosure. Mild change to the vent tuning (see next graph) but note the sensitivity difference- almost 5dB!
Now doesn't the impedance drop too low? Still within 4 ohm load (as expected- see cursor).
And what about the maximum SPL- an extra 3dB!
So 5dB high voltage sensitivity and 3dB higher maximum SPL in the same sized cabinet.
What's the catch?
Sorry about your wallet.
Hi !
since many years I have a REL sub, it does a fine job. Depending on the match with the speakers it is always more or less set to 35 - 40 Hz. The result is fine in my room.
Sine the Halcyons were completed I removed the sub because the go so low. So it is possible to have plenty bass in this room although many other speakers could not do it !
Whan I want to know is : am I right in thinking that a bigger woofer will make more real / natural bass than a smaller one ?
Happy Sunday
I have some experience with pairs of the Dayton RS225-8 in the Statements II
You've built the Halcyons and liked it?
It makes it easy to recommend: Anthology II
some chatter here at diyAudio
You've built the Halcyons and liked it?
It makes it easy to recommend: Anthology II
some chatter here at diyAudio
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Is that midrange driver a B&W driver and where did you get it?
In my old speaker configuration, I have the similar Focal 7K2 driver..
0407201529_HDR by drjlo2, on FlickrI would say 2 x 8" in the way that Wilson have it in Puppy and Sasha have one big advantage over a single driver and that is the 6-12dB dip created by first reflection from floor. With two drivers, where one of them are placed midways between upper driver and floor will make the frequency response considerably more linear in the 100-200 Hz region (If placed at approx. the same height as Wilson do.)