Hi everyone,
As I think about building some bass towers next year I am reminiscing about some of the most exceptional speakers I ever heard, the Snell A/III. Among the attributes I was impressed by was the bass performance. Just outstanding feeling that the speakers were pushing all the air in the room at once. I believe it's also called coupling to the room. As I recall, these speakers had a smallish 4" mid and tweeter in a hemispherical baffle in a separate enclosure which sat on top of an over large bass cabinet. There was quite a bit of distance between the mid and the floor slot.
Another attribute which I learned later was that the woofer was mass loaded. Sadly a reason so many have now failed.
On the negative side, these speakers were very sensitive to the amps used and as I recalled seemed to really not perform well at all with tubes.
My question for any who remember, or want to opine, is what made those speakers perform so well in the bass range?? Was it the floor firing woofer? The mass? something else?
I'm thinking about this in large part because I would love to recreate that experience, but not necessarily the design choices. Maybe knowing how Snell achieved the performance will help me put some of that into my next build.
Thank you,
Erik
As I think about building some bass towers next year I am reminiscing about some of the most exceptional speakers I ever heard, the Snell A/III. Among the attributes I was impressed by was the bass performance. Just outstanding feeling that the speakers were pushing all the air in the room at once. I believe it's also called coupling to the room. As I recall, these speakers had a smallish 4" mid and tweeter in a hemispherical baffle in a separate enclosure which sat on top of an over large bass cabinet. There was quite a bit of distance between the mid and the floor slot.
Another attribute which I learned later was that the woofer was mass loaded. Sadly a reason so many have now failed.
On the negative side, these speakers were very sensitive to the amps used and as I recalled seemed to really not perform well at all with tubes.
My question for any who remember, or want to opine, is what made those speakers perform so well in the bass range?? Was it the floor firing woofer? The mass? something else?
I'm thinking about this in large part because I would love to recreate that experience, but not necessarily the design choices. Maybe knowing how Snell achieved the performance will help me put some of that into my next build.
Thank you,
Erik
I did a poor job of describing the A/III, but Stereophile does a better job. It used a 12" floor firing woofer in a 2.9 cubic foot cabinet, in large part due to research by Roy Allison.
The source position was something Allison was interested in. It's possible the floor port was responsible for avoiding floor cancellation frequencies.
A port has mass. Mass loaded is usually used to describe a transmission line that ends in a port, however it could mean other things.
A port has mass. Mass loaded is usually used to describe a transmission line that ends in a port, however it could mean other things.
Many years ago, I built some interesting but simple loudspeakers.
Consisting of a church organ style reed based 1" Birch Ply case to house the 8" loudspeaker in one end, facing out of the case with a 1/4" Birch Ply reed from top to bottom.
The reed helps the lower register increase in sensitivity and produced a well balanced result from an otherwise lacking amplifier.
Sadly my drawings are long gone but I will attempt to reproduce them as I sold many pairs.
Consisting of a church organ style reed based 1" Birch Ply case to house the 8" loudspeaker in one end, facing out of the case with a 1/4" Birch Ply reed from top to bottom.
The reed helps the lower register increase in sensitivity and produced a well balanced result from an otherwise lacking amplifier.
Sadly my drawings are long gone but I will attempt to reproduce them as I sold many pairs.
The non-close floor coupling of woofers and its associated 150 Hz dip has even been referred to as the Allison Effect.
https://www.audiosciencereview.com/...fect-on-frequency-response-in-the-room.49791/
As I understand the Snell approach the woofer was indeed close coupled to the floor, even closer than with the AR9 and the Allisons.
But the claimed magic was not enough to persuade other manufacturers to follow that approach: KEF and B&W e.g. remained faithfull to classic woofer placement in their flagship models.
https://www.audiosciencereview.com/...fect-on-frequency-response-in-the-room.49791/
As I understand the Snell approach the woofer was indeed close coupled to the floor, even closer than with the AR9 and the Allisons.
But the claimed magic was not enough to persuade other manufacturers to follow that approach: KEF and B&W e.g. remained faithfull to classic woofer placement in their flagship models.
@AllenB - Apologies for the confusion. In this case, per my poor memory, some versions of the Snell A used woofers with additional mass added to them in the form of poured epoxy. This was effective but in the long term caused premature failure of the suspension. That's what I meant by mass-loaded driver.
I hear things about woofers near the ground being a compromise. I honestly don't see it, assuming they are crossed low enough. This seems the ideal placement, no?
All true. I have to say that the "claimed magic" for me was very real. I had never read anything about Snell before I heard the A/III and remain fascinated by them to this day. If I was a billionaire instead of buying a social media company I'd attempt to recreate some of the features with modern drivers, such as the hemispherical baffle. OTOH, the Sonus Faber Stradivari has much of the same sonic qualities and honestly, prettier. I just don't have the room /money to build such wide speakers. 😢
In my opinion, there is a significant advantage to placing the woofer near the floor. Of course this forces compromises in other aspects of the design, but the bass performance in the mid to upper bass can be really nice.
If we assume a single woofer, with the center of the driver at 12" (300 mm) of the floor, and assuming the midrange driver is about ear-level, a crossover frequency of 200 -300 Hz will work well. Above 300 Hz and the distance from woofer to mid starts to create some issues.
The ubiquitous tower speaker with twin woofers has some advantages here, because one of the woofers will be close to the floor. A stand-mounted monitor (such as Neumann KH420 or JBL L100) will always have a floor reflection that affects the upper bass to lower midrange. This can make placing the speaker in the room more challenging.
I never got a chance to hear any of the Snell speakers...
j.
If we assume a single woofer, with the center of the driver at 12" (300 mm) of the floor, and assuming the midrange driver is about ear-level, a crossover frequency of 200 -300 Hz will work well. Above 300 Hz and the distance from woofer to mid starts to create some issues.
The ubiquitous tower speaker with twin woofers has some advantages here, because one of the woofers will be close to the floor. A stand-mounted monitor (such as Neumann KH420 or JBL L100) will always have a floor reflection that affects the upper bass to lower midrange. This can make placing the speaker in the room more challenging.
I never got a chance to hear any of the Snell speakers...
j.
I'm also a fan of 100-150 hz cut off for middle sized rooms and speakers.
The Snell was indeed good (had the luck to listen once), have a good souvenir of it.
Maybe you could try the poor man strad from Troels but with sligthy different drivers. (but the cut off is higher iirc)
Also an hybrid if you can recess the loudspeaker from the wall is for you ? sealed <100 Hz, OB or LB from 100 Hz vinicity to ??? 600 hz/800 Hz then a FR (MarkAudio ?) to make it 3 ways and not 4 ways ?!
Should be challenging w/o MiniDSP like solution.
Of course the next good choice is the classic 10/12" sealed at 200/300 Hz cut off , a good 4" to 5.5" paper (papy russe like) then the tweeter of your choice with the patern you like the most.
My main is still a band pass sealed acoustic cut off at circa 100 Hz then mid up to 2100 hz circa. The Kef 104/22 was made also a little like that and I loved that speaker ! (he lacked just a littlemore deep bass). With a 12" an F3 at 40/45 hz will be a little a challenge but you won't miss anything, it is really enough. And if the room is not 40 square meter a 10" will do, imho. Sealed is the key.
Dunno if that helps much... my 2 cents anyway. Poor Man Strad is anyway feasible thanks to TG and in free access.
The Snell was indeed good (had the luck to listen once), have a good souvenir of it.
Maybe you could try the poor man strad from Troels but with sligthy different drivers. (but the cut off is higher iirc)
Also an hybrid if you can recess the loudspeaker from the wall is for you ? sealed <100 Hz, OB or LB from 100 Hz vinicity to ??? 600 hz/800 Hz then a FR (MarkAudio ?) to make it 3 ways and not 4 ways ?!
Should be challenging w/o MiniDSP like solution.
Of course the next good choice is the classic 10/12" sealed at 200/300 Hz cut off , a good 4" to 5.5" paper (papy russe like) then the tweeter of your choice with the patern you like the most.
My main is still a band pass sealed acoustic cut off at circa 100 Hz then mid up to 2100 hz circa. The Kef 104/22 was made also a little like that and I loved that speaker ! (he lacked just a littlemore deep bass). With a 12" an F3 at 40/45 hz will be a little a challenge but you won't miss anything, it is really enough. And if the room is not 40 square meter a 10" will do, imho. Sealed is the key.
Dunno if that helps much... my 2 cents anyway. Poor Man Strad is anyway feasible thanks to TG and in free access.
@diyiggy What I did not mention in this thread is that this will be a fully active design using a Hypex 3-way plate amp. My current "bookshelf" speakers are 2-way passive on stands. My goal is to fit the tower under them and convert the whole thing to an active 3-way.
I love wide baffle speakers but no room and beyond my budget right now. I have to have others build the cabinets (Solen.ca) so want to stay affordable. IMHO, the magic of the Strads isn't the driver quality so much as the wide baffle and excellent crossover.
I love wide baffle speakers but no room and beyond my budget right now. I have to have others build the cabinets (Solen.ca) so want to stay affordable. IMHO, the magic of the Strads isn't the driver quality so much as the wide baffle and excellent crossover.
So the challenge is imo to find the good mid that is going low enough w/o being too large for a better soundstage (5" max ?). Most of the good sounding one needs 300 Hz cut off. 250 Hz if no listening too loud (flats). Maybe the trade off could be a Revelator here.
If you think it twice the band pass à la Kef 104/2 cabinet is clever. It exploits all the verticality of the box for the bass load, use push pull cancelation, the band pass filtering helps a little to the resonances of the bass drivers (but left up another one, filtering can be tricky but you're active). Then the mid treble front baffle that can be made diy with two mdf sheets adds some mass and decoupling with good recess of the sides for good soundstage (they disseaper in theroom litterally). Todat I will round it à la Joachim Gherardt in what he mades for even better smoothing. Chellnge here is to find the good sealed that work with low VAS as the Kefs drivers.
The variation With a baffle less 100 hz to up is more challenging (10" to 12" with goodXmax and a LR transform), ask Juha here. Bass : sealed good 10" bass, LROY4 in 30/40L sealed ?
The variation With a baffle less 100 hz to up is more challenging (10" to 12" with goodXmax and a LR transform), ask Juha here. Bass : sealed good 10" bass, LROY4 in 30/40L sealed ?
By making separate subs and placing those in very close range to your listening spot you will experience that effortless enveloping deep bass in your own room.
Many moons ago I built the Audio Concepts Titan, a simple, closed box push-pull compound system using two fairly basic AC12 woofers, close coupled to the floor. After endless experimenting with placement -it all sounded problematic in the beginning- I finally settled for placement side by side of my two seater couch-listening spot. Than the magic unfolded, and all that for a few hundred of dollars. Speaker Builder's reviewer Gary Galo ended up using the same placement in his review of the Titans.
Since than even cost no objective systems that do not properly deal with rooms modes sound unbearable to me. After moving I disassembled the Titans, but in more than 30 years I never got back what I then gave up.
Many moons ago I built the Audio Concepts Titan, a simple, closed box push-pull compound system using two fairly basic AC12 woofers, close coupled to the floor. After endless experimenting with placement -it all sounded problematic in the beginning- I finally settled for placement side by side of my two seater couch-listening spot. Than the magic unfolded, and all that for a few hundred of dollars. Speaker Builder's reviewer Gary Galo ended up using the same placement in his review of the Titans.
Since than even cost no objective systems that do not properly deal with rooms modes sound unbearable to me. After moving I disassembled the Titans, but in more than 30 years I never got back what I then gave up.
At Érick, what you heard in the Snell was a whole : bass + MIDWOOFER. (snap drum behavior + articulation is important factor in the 100 hz to 200 hz circa.
IMHO, you will be good with a QTC around 0.6 for your bass sealed, something between over damped and max flat of the 0.7 : active you can easily trimm that as if you put 1 uf then 0.1 uF shunt in a secpnd order lo pass for instance. It is what I did at setuping my bandpass (Boston Acoustic Lynnfield serie : the high end ones), I was surprised to hear 0.1 uF (shunt of a 2nr order low pass) at the end made a difference on the articulation and weigth in a 40 square meter room, with an acoustical cut off as low as 100 Hz ( 115 electrical).
What is your 7" ? He will be plenty of energy in the low, the soundstage will not be as good as the Snell, though I believe.
IMHO, you will be good with a QTC around 0.6 for your bass sealed, something between over damped and max flat of the 0.7 : active you can easily trimm that as if you put 1 uf then 0.1 uF shunt in a secpnd order lo pass for instance. It is what I did at setuping my bandpass (Boston Acoustic Lynnfield serie : the high end ones), I was surprised to hear 0.1 uF (shunt of a 2nr order low pass) at the end made a difference on the articulation and weigth in a 40 square meter room, with an acoustical cut off as low as 100 Hz ( 115 electrical).
What is your 7" ? He will be plenty of energy in the low, the soundstage will not be as good as the Snell, though I believe.
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(the idea of a littlier sized Revelator was because they are snappy there for their little size and extend higher as you know of course for the tweeter cut off).
If close of the sofa, could also be made open baffle à la Linkwitz : win-win : articulation + neighbour quietness !
I'm using a 6.5" SS Revelator woofer already. Really not changing it for this project. But I will probably seal the cabinet and then make more choices from there.