Dunlavy Speakers

[Brent71]

I was quite interested in the Dunlavy speakers, back in the day. They used cheapish VIFA drivers that I used in a couple of designs I was working on at the time. They were using the D"appolito configuration (Dome tweeter in the middle, a midrange both above and below as well as woofers above and below the midranges. The crossovers were first order, so measurements would be poor in some locations but superb in others. Used in a large room so you could be a good distance from them, they blended well and sounded good. Luckily the drivers were a mineral filled polypropylene that rolled off smoothly so the first order crossovers were adequate

D'Appolito design requires 3rd or 4th-order crossovers.

John Dunlavy used only 1st-order crossovers, stepped baffles, and sealed enclosures, because it's the only way to get near-perfect step and impulse response; 2nd-order and steeper crossovers store energy and cause poor step and impulse response; ports cause the Q to go sky-high.

Dunlavy SC-VI step response. This shows how nearly perfectly time-aligned they are at a listening position of 10 feet, and it's a 7-driver speaker; really impressive!

 

[Daverz]

I owned a pair of Dunlavy MTM type speakers with two 5" drivers and a tweeter in the center. Forgot the model number. I think they were a vented design. They had absolutely no bass at all. Otherwise, they were okay. I owned a pair of 2-way speakers with a six-inch driver, and that trounced the Dunlavys, bass-wise.

I don't remember a vented model. The reason the small ones had no bass is that they were sealed, used first-order crossovers.

D'Appolito design requires 3rd or 4th-order crossovers.

John Dunlavy used only 1st-order crossovers, stepped baffles, and sealed enclosures, because it's the only way to get near-perfect step and impulse response; 2nd-order and steeper crossovers store energy and cause poor step and impulse response; ports cause the Q to go sky-high.

Dunlavy SC-VI step response. This shows how nearly perfectly time-aligned they are at a listening position of 10 feet, and it's a 7-driver speaker; really impressive!
View attachment 341544

Of course, these days anyone with a measurement microphone and the right software can get a similar step response (at the listening position).

Step response of a a 2.1 system with Buchardt S400 mains and an SVS SB-1000 Pro corrected by Acourate.

 

[Brent71]

I don't remember a vented model. The reason the small ones had no bass is that they were sealed, used first-order crossovers.


Of course, these days anyone with a measurement microphone and the right software can get a similar step response (at the listening position).

View attachment 341549

Step response of a a 2.1 system with Buchardt S400 mains and an SVS SB-1000 Pro corrected by Acourate.

That's pretty cool. I know just about nothing when it comes to that stuff, way above my pay grade. I wish I did have a clue about DSP, I think it would be nice to eliminate the passive crossovers in my SC-Vs and go the route John Dunlavy wanted to go with DSP and separate channels of amplification for tweeter, mids, mid-bass and woofers.

 

[G|force]

I did that with a pair of JBL 4343 4-ways. Subjective improvement in every area. If I had a pair of SC-V or SC-VI I would not hesitate.

 

[Daverz]

That's pretty cool. I know just about nothing when it comes to that stuff, way above my pay grade. I wish I did have a clue about DSP, I think it would be nice to eliminate the passive crossovers in my SC-Vs and go the route John Dunlavy wanted to go with DSP and separate channels of amplification for tweeter, mids, mid-bass and woofers.

I've considered projects on a smaller scale, such as replacing the electronics for my NHT Xd system. But when I add up the cost of all the electronics needed -- and those are just 2-ways -- I could buy some pretty nice speakers instead.

 

[Holmz]

….

John Dunlavy used only 1st-order crossovers, stepped baffles, and sealed enclosures, because it's the only way to get near-perfect step and impulse response; 2nd-order and steeper crossovers store energy and cause poor step and impulse response; ports cause the Q to go sky-high.

Dunlavy SC-VI step response. This shows how nearly perfectly time-aligned they are at a listening position of 10 feet, and it's a 7-driver speaker; really impressive!
View attachment 341544

The problem here is that most people only care about frequency response, and few care about time do response (step function and impulse response).
And furthermore the idea of phase coherent is also low on most peoples lists.

it is pretty much FR Uber Alles, and time alignment without a notion of whether it is 0 degrees or 180 degrees out.

 

[HionHiFi]

I owned a pair of SC-V’s a few years back now. They were the big boys at the time. Best speakers I’d owned up to that time. Sadly, I had to sell them… wish I hadn’t. I’d have been done with speakers. I can still remember how I felt when I first heard them. The bass response was sublime. To this day I’ve never heard bass like that. Of course the SC-V’s are huge.

Dunlavy wrote a series of articles in Widescreen Review Magazine called Loudspeaker Accuracy in Feb 2007 - Aug 2007, Newsletter 09-15. I couldn’t find it online but I have it downloaded if you want a copy. It’s a masterclass of loudspeaker design according to John.

 

[egellings]

I don't remember a vented model. The reason the small ones had no bass is that they were sealed, used first-order crossovers.


Of course, these days anyone with a measurement microphone and the right software can get a similar step response (at the listening position).

View attachment 341549

Step response of a a 2.1 system with Buchardt S400 mains and an SVS SB-1000 Pro corrected by Acourate.

It's likely mine were sealed, then, but I don't remember.

 

[MattHooper]

I owned a pair of SC-V’s a few years back now. They were the big boys at the time. Best speakers I’d owned up to that time. Sadly, I had to sell them… wish I hadn’t. I’d have been done with speakers. I can still remember how I felt when I first heard them. The bass response was sublime. To this day I’ve never heard bass like that. Of course the SC-V’s are huge.

Dunlavy wrote a series of articles in Widescreen Review Magazine called Loudspeaker Accuracy in Feb 2007 - Aug 2007, Newsletter 09-15. I couldn’t find it online but I have it downloaded if you want a copy. It’s a masterclass of loudspeaker design according to John.

Wow, SC-Vs! That's commitment! Must have been magnificent.

 

[HionHiFi]

Wow, SC-Vs! That's commitment! Must have been magnificent.

Commitment, is the right word. I don't like to talk about it. I wish I'd never sold them. It brings tears to my eyes !

 

[norman bates]

Full range drivers with whizzes have a bit of phase variance.

DECWARE - Audio Paper - Understanding high efficiency full range drivers

A flagship audiophile website featuring the personality of audio guru Steve Deckert, with many articles on high fidelity and acoustics to read you can also find online forums, stereo classifieds and his line of Zen Triode tube gear

www.decware.com

Actually, this isn't too bad phase changing for a 6" with whizzer.

Rethm Maarga loudspeaker Measurements

Sidebar 3: Measurements

www.stereophile.com

 

[Anthony LoFi]

I see now and again Duntech and Dunlavy advertised in Australia.

https://www.gumtree.com.au/s-ad/hallett-cove/speakers/duntech-emerald-speakers/1320164217

 

[dfuller]

Well, the axial response of the SC-VI is certainly pretty good (courtesy Stereophile) No directivity plots though.

 

[ahofer]

I remember listening to Duntech Sovereigns, and being very impressed. 1981, must have been.

I’m sure you all recognize it as the most accurate loudspeaker in the world, per their website:

Sovereign - Duntech

somehow the Princess is also the most accurate loudspeaker in the world.

 

[Brent71]

I remember listening to Duntech Sovereigns, and being very impressed. 1981, must have been.

I’m sure you all recognize it as the most accurate loudspeaker in the world, per their website:

Sovereign - Duntech

somehow the Princess is also the most accurate loudspeaker in the world.

I'd like to see the measurements to see if that's actually true. When JD was still at Duntech the Sovereign's were the most accurate speakers in the world, but he outdid them with the DAL designs. Straight from JD himself:
"And no! The speakers I designed in Australia did not exhibit the level of accuracy of our present designs because I had neither a decent, large anechoic chamber or the measurement capabilities available with the MLSSA system, time-domain spectrometry, and other gear we presently use."

 

[Daverz]

I've got my SC-IIIs out for a spin. These have been sitting unused for many years, and they may be 25 years old (I bought them used in 2001 or 2002). They are definitely not ideal for my room, I have to put them very near the front walls (I don't even have one continous wall for them) so that I can sit back 3 meters from them, and can only get them a little more than 3 meters apart (and even that is a bit awkward`).

Subjective impressions for what they are worth: center image is quite strong, they image very well, though images are a bit more diffuse than my Buchardt S400s. Being 6 feet tall, they give a nice sense of scale. Treble is good, but not as smooth or extended as the S400s. Bass is more satisfying than I remember. Specs give an F6 of 35 Hz, so they may not need a subwoofer for most of my listening. There is a bit of "shoutiness", but that may be due to the room.

In room measurement with psychoacoustic smoothing:

I wonder what's causing the broad dip before 1 kHz, perhaps reflections from the front wall.

EDIT: there were measurements of the SC-III by Bascom King:

Dunlavy Audio Labs SC-III loudpeaker (July 1998)

EDIT: I generated some correction filters with Acourate, and they did smooth out the shoutiness that I heard.

EDIT: I was aligning the sub today and measured the mains alone again, and now that dip is gone. So human error (then or now) or something else...

 

[phantompowered]

I've come across a pair of SC-II for sale local to me that are fairly affordable.

I'm a big fan of Dunlavy's design approach and the SC-IV stands out as one of the best speakers I've ever heard, but the impression I get from the very limited online discussion I have been able to find is that the SC-II is significantly lacking in the low end without a sub, which I cannot make happen as I'm in an apartment.

Is this an accurate descriptor? My current speakers are B+W 804Ss, which have a pretty decent, though not chest-rumblingly spectacular, low frequency response from two 6.5inch woofers and one mid-range driver, which is nearly the same configuration of drivers in the Dunlavys with the exception of the extra mid-range unit.

Thoughts? Feelings? Measurements?

 

[norman bates]

I remember him saying (loosely), "If you wouldn't buy an amp or CD player that can't pass a square wave, why would you buy a speaker that can't ?"

I would buy those speakers, but I have a problem wanting to play with all this stuff.....

 

[DSJR]

Anybody know anything about these? A mastering engineer friend swears by them (I think he uses SC-Vs), but I can't say I've ever heard them. What's their claim to fame?

Not Simon Heyworth by any chance (Super Audio Mastering)?

 

[Daverz]

I've come across a pair of SC-II for sale local to me that are fairly affordable.

I'm a big fan of Dunlavy's design approach and the SC-IV stands out as one of the best speakers I've ever heard, but the impression I get from the very limited online discussion I have been able to find is that the SC-II is significantly lacking in the low end without a sub, which I cannot make happen as I'm in an apartment.

Is this an accurate descriptor? My current speakers are B+W 804Ss, which have a pretty decent, though not chest-rumblingly spectacular, low frequency response from two 6.5inch woofers and one mid-range driver, which is nearly the same configuration of drivers in the Dunlavys with the exception of the extra mid-range unit.

Thoughts? Feelings? Measurements?

My SVS SB-1000 Pro sub has a setting to roll off the response at 40 Hz, as well as 3 PEQ filters available, and, of course, a volume setting -- all of this available on their phone app -- so you have various ways to tamp down the low bass when the neighbors are around.