On a slight tangent, I see more and more commercial speakers with 3 woofers. The typical architecture is a slim tower with 3 vertically aligned 8" or 6.5" woofers
Some examples:
Revel Performa 328
B&W 702 S3
JBL HDI 3800
Martin Logan Motion XT F200
Focal Aria EVO X No. 3
I wonder how these are wired? It is hard to imagine that these use standard 4 or 8 Ohm drivers, since the resulting impedance would be too high or too low. If I were the designer, I would wire them in parallel, and specify either 12 Ohm or 16 Ohm drivers. But I suppose they could use 2 Ohm drivers wired in series... ?
j.
Some examples:
Revel Performa 328
B&W 702 S3
JBL HDI 3800
Martin Logan Motion XT F200
Focal Aria EVO X No. 3
I wonder how these are wired? It is hard to imagine that these use standard 4 or 8 Ohm drivers, since the resulting impedance would be too high or too low. If I were the designer, I would wire them in parallel, and specify either 12 Ohm or 16 Ohm drivers. But I suppose they could use 2 Ohm drivers wired in series... ?
j.
Pretty sure they are custom ordered impedance drivers because they have the buying power. Likely 12-16 ohm range, unless xover is very low and uses 3x 8-10 ohm in parallel with a big fat coil.
Most of them TTBOMK are using custom versions of the drivers with 16ohm coils.
That being said, the number of commercial speakers I see which dip to 2ohms or < is a mite depressing. Especially since they usually command huge prices...
That being said, the number of commercial speakers I see which dip to 2ohms or < is a mite depressing. Especially since they usually command huge prices...
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Yes.
In series, one dies - open circuit.
I parallel, ones dies, the other one dies very soon after - open circuit.
There are commercial speakers which use two 8 inch woofers and which are two ways which have crossover points well above 800Hz.JBL Studio 590 for example.Also some of the older B&W like the 202 which crossed at about 2500Hz.They used 16 0hm drivers in parallel.
I grabbed two "identical" 6" mid-woofers from my stash, and ran an impedance sweep with one by itself and then both wired in series.
DCR is doubled. Le is doubled, Impedance is doubled. Slight variation is likely due to them not being exactly "identical" 😉
Attachments
Also, if you have a rather low current amplifier, you get voltage/power sag when driving 4 ohms compared to 8 ohms.
A truly 'gutsy' amp. will give exactly double power into 4 ohms compared to 8 ohms.
The 600Hz to 4Khz midrange section of my 'Twin Towers' is open baffle and uses a vertical array of six 5.5" 4 ohm drivers.
These drivers are wired parallel/series to create a nice 6ohm load for the crossover design. With a touch of Zobel the impedance is super flat.
The array starts at 2'10" above floor level and ends at 6'3" above floor level. Because it's open baffle and its F range, TS parameters don't apply.
Because of its sheer expanse + listening room + distance from the speakers, I get a very big, open & coherent sound stage without noticeable
comb-filtering 🙂
These drivers are wired parallel/series to create a nice 6ohm load for the crossover design. With a touch of Zobel the impedance is super flat.
The array starts at 2'10" above floor level and ends at 6'3" above floor level. Because it's open baffle and its F range, TS parameters don't apply.
Because of its sheer expanse + listening room + distance from the speakers, I get a very big, open & coherent sound stage without noticeable
comb-filtering 🙂
Absolutely couldn't agree more.
Highly prefer 8 ohm and wouldn't even care moving up to 16 if more available.
Once involved with basic to extended amplifier design.
You just appreciate friendly loads even more.
Why wouldn't the driver Thiele–Small (TS) parameters apply?
This is quite different from using a point-source design approach. I wonder which of the two design approaches is producing the more accurate sound stage? Is the less accurate sound stage result going to be preferred under some circumstances?
I love point-source / dual concentric speakers for near-field monitoring / listening > it can't really be beat IMO.
But listening at a significant distance from the speakers in a large room with open baffle design is quite a different situation.
Large diaphragm operating area really comes into its own in such an environment.
This is why I have per Ch. > a 15" sub. + 12" bass + vertical array + bi-polar tweeters. It is a room filling experience, much like live music.
The TS parameters of the mids I say aren't applicable are those related to enclosure design, and the other Q's are also not relevant when
it comes down to the natural sound of the drivers 🙂
PS.
I love 'classic Tannoys' > great sound at a moderate distance.
But listening at a significant distance from the speakers in a large room with open baffle design is quite a different situation.
Large diaphragm operating area really comes into its own in such an environment.
This is why I have per Ch. > a 15" sub. + 12" bass + vertical array + bi-polar tweeters. It is a room filling experience, much like live music.
The TS parameters of the mids I say aren't applicable are those related to enclosure design, and the other Q's are also not relevant when
it comes down to the natural sound of the drivers 🙂
PS.
I love 'classic Tannoys' > great sound at a moderate distance.
Someone told me once that two driver in series, if their resonant impedance peak doesn't match exactly (pretty common) then they won't share the load evenly through that frequency space, electrically speaking. But if you have them in parallel then each driver can drink their fill. But I haven't heard anyone else mention this as a concern.
Think it's a thing?
Think it's a thing?
With very cheap & poor quality drivers such a situation can exist, but even then, it probably wouldn't be too significant.
With decent quality drivers, such a thing would be of little significance.
PS.
The more the quantity of drivers in a series/series parallel situation the more the average 'settles - out'.
It is when combining completely different drivers that things can become quite problematic.
With decent quality drivers, such a thing would be of little significance.
PS.
The more the quantity of drivers in a series/series parallel situation the more the average 'settles - out'.
It is when combining completely different drivers that things can become quite problematic.
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I once listened to a large set of Tannoy loudspeakers, and they were able to achieve high SPLs with ease. However, natural sound reproduction did not seem to be their forte. If the reproduction of electronically amplified music is the goal, then a room-filling, high-SPL live sound experience could be expected to be somewhat PA-style in its sound quality. This seems to be borne out when listening to acoustic instruments being replayed over such systems, which seem to tend to imprint their own character on the reproduced sound.
If "a large set of Tannoys" means more than a single pair, you would run into definite comb-filtering problems. BUT >
If you're referring to a single stereo pair, I disagree. In a past job of mastering, the in-wall Tannoys exhibited excellent clear fidelity.
When it comes to high SPL reproduction of music NOT sounding like a PA > that is the art of excellent speaker design VS a noisy mess.
PS.
Today there are actually TWO kinds of PA systems > Cheap & Nasty VS very expensive using Super Drivers, Time alignment and massive headroom.
PS.PS.
"electronically amplified music" is what we ALL listen to 😎
If you're referring to a single stereo pair, I disagree. In a past job of mastering, the in-wall Tannoys exhibited excellent clear fidelity.
When it comes to high SPL reproduction of music NOT sounding like a PA > that is the art of excellent speaker design VS a noisy mess.
PS.
Today there are actually TWO kinds of PA systems > Cheap & Nasty VS very expensive using Super Drivers, Time alignment and massive headroom.
PS.PS.
"electronically amplified music" is what we ALL listen to 😎
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