[Tim Diebert]

Hey guys & gals!

I thought I’d share with you all my recent subwoofer build. After owning many subwoofers over the last 20yrs, running through all the normal sizes...8” 10” 12” 15”....a few of the basic designs....sealed, ported, passive radiator, bandpass, I decided I wanted to jump into the world of larger drivers. Yes I know we have access to 21” 24” & possibly larger subwoofers, but I personally wanted to see what a top of the line 18” driver is capable of in my home.

My living room is not very large, totaling approx 225sqft (13.5’x 15.5”x 8.5’). I can however close that area off to the rest of the home. If I shut all the adjacent doors leading to rooms/kitchen/dining I’m able to gain some mid-bass impact & pressurization.

After a LOT of research I decided that I wasn’t going to cut any corners with the driver I purchase. I became aware of Harbottle Audio, a few years ago, who work in tandem with Funk Audio. Harbottle Audio has developed a driver that is an absolute diamond in the rough. The Ridge 18vS (18 version studio). The fundamental design theory behind all of their driver developement is Low Distortion Low Compression aka LDLC. Designing from that standpoint is what really sets them apart from most if not all other subwoofer manufacturers on the market. It’s a MUST read for any of you enthusiasts & there is a great write up on the Harbottle Audio website. I highly recommend checking it out.

Once I spoke with Cody Hiebert, owner of Harbottle Audio who designs the drivers alongside Nathan Funk of Funk Audio & was given a short lesson on what his drivers are capable of, I was convinced. Well...that & also the incredible track record of this driver along with all their other products.

I think that’s enough babbling from me. I know you all clicked on this to see the pics. I’ll be putting together my thoughts on it’s performance in the near future. I’ll probably write up a full review on a separate thread. So keep an eye out for that if you’re interested because I can tell you this, the 18vS driver is doing something I NEVER thought an 18” subwoofer could do!!

• Hint: It’s crossed over at 200hz

DRIVER:
Harbottle Audio - Ridge 18vS
dual 4ohm
w/upgraded solid carbon fiber cone

AMP:
Funk Audio M1
1000w RMS/2000w Peak
w/DSP

ENCLOSURE:
19.5w X 24”h X 21”d (4cuft)
3/4” Baltic birch including bracing
1.5” baffle
Sound deadening & 2” foam lining interior

FEET:
SVS Soundpath x4

EDIT:
•••CLICK HERE FOR DEMO•••

And now the pics!!.......

 

[Tim Diebert]

 

[Tim Diebert]

 

[(The Other) Colin Miller]

Hmmm...

You're making me wonder if I can do a straight swap with the Dayton/China Ultimax 18's I just finished building cabinets for, only to discover that my drivers are 50% out of spec, and PE thinks that's normal and fine.

Nice job BTW. Looks fantastic.

 

[BP1Fanatic]

The right tower looks lonely tho'....beautiful driver!

 

[HarbottleAudio]

Hmmm...

You're making me wonder if I can do a straight swap with the Dayton/China Ultimax 18's I just finished building cabinets for, only to discover that my drivers are 50% out of spec, and PE thinks that's normal and fine.

Nice job BTW. Looks fantastic.

Sad to say, but that is normal. +/-10% is a starting point for drivers in full production when they are manufactured to industry standards, and as you see, that isn't a hard ceiling but more like a loose suggestion. As a comparison, we offer +/-5% on conceptual drivers (not in production, only concept designs), and +/-0.5% in end performance on our full production models.

 

[Tim Diebert]

Hmmm...

You're making me wonder if I can do a straight swap with the Dayton/China Ultimax 18's I just finished building cabinets for

I know PE recommends their 4cuft flat pack for the ultimax 18”. So if you built sealed enclosures that are 4cuft or close to that then yes you can drop the Ridge 18vS into those. You can check the cutout diameter needed for the 18vS on their website harbottleaudio.com but I do believe the ultimax diameter is identical or close enough.

What amp do you have for your subs currently?

 

[Tim Diebert]

The right tower looks lonely tho'....beautiful driver!

Thank you!

Oh TRUST me!....I know
I’m hoping to remedy that in the future.

I have an enclosure I made for abother driver that I didn’t end up using. A few months ago I set it up next to my right main just to see how duals would look. Believe me that thought has already run through my mind hahaha

 

[Ennsio]

That's an awesome looking sub! Nice work. I'm very interested to hear more of your impressions of its performance since I have ordered the same 18vS driver and the M18 enclosure from Harbottle Audio and they will be arriving in January.

 

[Tim Diebert]

That's an awesome looking sub! Nice work. I'm very interested to hear more of your impressions of its performance since I have ordered the same 18vS driver and the M18 enclosure from Harbottle Audio and they will be arriving in January.

Well, without giving too much away, you WONT be disappointed!!

What sub, if any, do you currently have?

 

[(The Other) Colin Miller]

Sad to say, but that is normal. +/-10% is a starting point for drivers in full production when they are manufactured to industry standards, and as you see, that isn't a hard ceiling but more like a loose suggestion.

Yeah, I was thinking I would swallow +/- 10%, not a big deal, but the degree of variance was annoying. That being said, the way it varied in terms of real world results, I don't think most people would have noticed, and if I wasn't a picky snoodler I don't think I would have noticed. The Fc was higher than it 'should' have been, but so was the Qtc (and in most applications for most people, who cares?), so the F3 wasn't that far off, so even if you were measuring the output in-room, you would probably dismiss any variance from what was expected as a difference in 'room gain', or what not. I have yet to spend the time dialing it in, but it wasn't that hard to get it actually flat-like down to 20 Hz with a shelving filter, and it doesn't itself sound bad, and I think most people would be just fine with the 'thunky' character of the higher Qtc. It's not boomy, and with some more tuning of the EQ, and placement, and maybe after tweaking the crossover relationship with the rest of the system (the pair of drivers doesn't seem to blend nearly as well as the relatively cheap velodyne CHT10 that they replaced, though I don't know if that is because of the drivers or because the physically larger enclosures changed the phase relationship due to the drivers being more forward in the room, I will try rotating them later). I think they have a shot at sounding pretty okay... but realistically I can't see them handling the low stuff in Can's "Last Night Sleep" with the same deftness of my TC sounds 12 inch subs in the other room.

While I do think that the UM-18 is still of good value in terms of build and materials for what you pay, I think that in retrospect my expectations, while not unfounded based on the information I had, were a bit unrealistic. Or maybe they weren't. I don't know. Regardless, it has been a good learning experience, and when the irritation fades, it's still interesting.

But despite them probably still being a good value for the money, they aren't what I was looking for, and they're certainly not the same drivers that were tested at data-bass.com, which is the main reason I pulled the trigger on them in the first place. What I really wanted was something not just with low distortion and extension (via reasonable EQ is fine with me), but something that did it starting with a slightly overdamped starting points, so that I could tune the degree of 'thick thunk presence' balancing to taste with EQ, and if necessary playing with box stuffing material. Tactile response certainly is of no detriment, but what I really want is as close as I can get to good 'headphone bass'.

I shall definitely be playing with your driver data, and maybe watching for the upcoming group buys, and when ready maybe even bothering you with a phone call or two. I think the UM-18s can get me by for the holidays, but I don't think they're going to be the last stop on the living room subwoofer train.

As a comparison, we offer +/-5% on conceptual drivers (not in production, only concept designs), and +/-0.5% on our full production models.

That's kind of insane (in a good way for your customers). Do you test them before they go out the door? How in the heck can you manage that kind of build tolerance?

I know PE recommends their 4cuft flat pack for the ultimax 18”. So if you built sealed enclosures that are 4cuft or close to that then yes you can drop the Ridge 18vS into those. You can check the cutout diameter needed for the 18vS on their website harbottleaudio.com but I do believe the ultimax diameter is identical or close enough.

I put them in a couple of these...
Denovo Audio Sledge M4-18s Baltic Birch 4.0cuft Subwoofer Flat-Pack for 18" Subwoofers. I like sealed just fine. While I certainly understand the benefits of reflex systems, and some of them sound great, they just aren't my priorities, generally speaking.

I like the cabinets, and while they're not exactly fine furniture grade, between the stain and the many layers of gunstock oil (it's not as smooth as a varnish, but it's really tough and easy to touch up), I like how they turned out, especially if my eyeballs aren't right up on them with a light creating a direct surface reflection from behind, which shows streaks like brush strokes because the oil was rubbed on, dries quickly. Anyway, I would like to keep them. I was cruising around the Harbottle website after finding this thread, and your write up, which re-sparked interest. I had heard of their drivers before (I think I sort of briefly met on a Facebook Group, Home Theater Enthusiasts before it grew a bit dense with... nevermind), but I didn't know they made 18's (or were thinking 12's or 15's on the way), and 24's were way more than I needed. I've noticed that some of the 18's have enclosure volumes that are spec'd even significantly lower on the minimum size, which could be theoretically appealing as well, so long as I'm really only giving up efficiency. Lots of new interest to explore! I was actually thinking of Stereo Integrity as well, though it would seem based on the data-bass.com information is that they put a little more emphasis at staying relatively clean with a huge dynamic range as opposed to pushing distortion a bit lower at the cost of a little less displacement capability. I have no doubt they're excellent drivers, but what pushed me to the Ultimax first wasn't primarily the lower cost, but that the distortion levels at levels more likely akin to my modest needs, particularly at higher frequencies, were significantly lower. Would that difference itself be audible? I don't know, but having and eating are both nice when it comes to cake.

What amp do you have for your subs currently?

Right now, and for the foreseeable future, a pair (or possibly 4 when I complete assembly) of IcePower 1000-ASP. My presumption is that driving dual 2 ohm coils in series would be the most sensible thing to do, though I also wonder about using two modules per driver and driving dual 4 ohm coils individually in tandem, if that were available. As I don't listen nearly that loud (I think) I would guess that the benefit would be more a novelty than a performance gain. But it would provide a rationale for the second box that will eventually occupy that 2 RU space in the living room rack... I suppose I could also use it to drive the 8" mid-bass modules. Perhaps ludicrous overkill, but that too would have some novelty value.

I know there's better bang/buck options out there, but I've had good experience with the 500-ASP versions that have done well by me for a very long time, both as subwoofer amplifiers, and as non-audiophile background music amps. , don't run hot, have and need no fans, and I really don't crank it nearly to the degree that some do, so I'm quite happy with them. Plus, I got to build my own 2RU high enclosure with vintage Carver-style handles, a brushed aluminum front plate, and a cute little blue power button dead center. For a cheapie Taiwan-made chassis, no complains. Supposedly you can connect LEDs to a couple of pins that can also be shunted to disable the internal limiters, and get clipping indicators as well, though my relatively modest output needs would probably make that more of a decorative effort than a useful feature. A friend of mine HAS blown these models of amplifiers up, but he lives in Hungary, has no immediate plans to visit, and because the maximum output is determined by me and hard coded into the control system, and eventually set to make playback loud enough to damage anything somewhere between unlikely and impossible, I'm not concerned. They supposedly have thermal safeties built in (which my friend tripped, repeatedly), but I'm more inclined to simply not go there. I guess I'm getting old.

Thank you!

Oh TRUST me!....I know
I’m hoping to remedy that in the future.

I have an enclosure I made for abother driver that I didn’t end up using. A few months ago I set it up next to my right main just to see how duals would look. Believe me that thought has already run through my mind hahaha View attachment 3069896

I think that will look very splendid. Plus, if you wanted, you could brag about that esoteric, (and supposedly available on a handful of recordings ) 'stereo' bass. But even if the main result was that it just looked cool... it sure would look cool!

 

[HarbottleAudio]

We QC each driver around 100 times depending on the motor type. Then we run each driver in a rig and check for noise. Then we measure params. Then we box the driver and run it at thermal capacity for a full duty cycle. Then we sign off and "approve for use".
We came up with these measures because we have used other drivers before we developed our own and found that we don't like dealing with driver issues and it's cheaper to fix the manufacturing process than to warranty and justify poor performance. So we just make the performance the same. A lot of it is actually in LDLC engineering that Nathan and I developed. It rides a razors edge between perfect and sounding terrible. But we measure and verify anyway because we need to know that you can run it at thermal limit without issue.

 

[(The Other) Colin Miller]

We QC each driver around 100 times depending on the motor type. Then we run each driver in a rig and check for noise. Then we measure params. Then we box the driver and run it at thermal capacity for a full duty cycle. Then we sign off and "approve for use".
We came up with these measures because we have used other drivers before we developed our own and found that we don't like dealing with driver issues and it's cheaper to fix the manufacturing process than to warranty and justify poor performance. So we just make the performance the same. A lot of it is actually in LDLC engineering that Nathan and I developed. It rides a razors edge between perfect and sounding terrible. But we measure and verify anyway because we need to know that you can run it at thermal limit without issue.

I don't think there's a 'like' button with an appropriate graphic to represent how much it pleases me to know that somebody actually does this.

And what does LDLC stand for?

 

[HarbottleAudio]

I don't think there's a 'like' button with an appropriate graphic to represent how much it pleases me to know that somebody actually does this.

And what does LDLC stand for?

Low Distortion Low Compression. It's boring but it's accurate.
Here is the paper I wrote on it.

About Harbottle Engineering

Harbottle engineering and standards

www.harbottleaudio.com

 

[Tim Diebert]

And what does LDLC stand for?

Low Distortion Low Compression

 

[Tim Diebert]

Low Distortion Low Compression. It's boring but it's accurate.
Here is the paper I wrote on it.

About Harbottle Engineering

Harbottle engineering and standards

www.harbottleaudio.com

I didn’t find it boring.
Actually very interesting & is what helped me appreciate just what these driver are doing. It’s a good read.

 

[Chris Popovich]

Yeah, I was thinking I would swallow +/- 10%, not a big deal, but the degree of variance was annoying. That being said, the way it varied in terms of real world results, I don't think most people would have noticed, and if I wasn't a picky snoodler I don't think I would have noticed. The Fc was higher than it 'should' have been, but so was the Qtc (and in most applications for most people, who cares?), so the F3 wasn't that far off, so even if you were measuring the output in-room, you would probably dismiss any variance from what was expected as a difference in 'room gain', or what not. I have yet to spend the time dialing it in, but it wasn't that hard to get it actually flat-like down to 20 Hz with a shelving filter, and it doesn't itself sound bad, and I think most people would be just fine with the 'thunky' character of the higher Qtc.

Put a linkwitz transform on that sucka and stop worrying about it. Dial in whatever Q you want.

Chris

 

[noah katz]

Yeah, I was thinking I would swallow +/- 10%, not a big deal, but the degree of variance was annoying. That being said, the way it varied in terms of real world results, I don't think most people would have noticed, and if I wasn't a picky snoodler I don't think I would have noticed. The Fc was higher than it 'should' have been, but so was the Qtc (and in most applications for most people, who cares?),

I'd care if a Qe that much higher was due to a weaker motor.

...we offer +/-5% on conceptual drivers (not in production, only concept designs), and +/-0.5% on our full production models.

Really?! I'd think the spider stiffness would change more than that just from temperature differences.

 

[HarbottleAudio]

I'd care if a Qe that much higher was due to a weaker motor.




Really?! I'd think the spider stiffness would change more than that just from temperature differences.

That was a typo on my part. It is corrected now. Our spec for conceptual designs are +/-5% but because the result is so tight, we actually can only measure the end performance at +/-0.5% variance.
In terms of temp, you have to ask what you are measuring and when you are measuring it. Since we design for maximum output at thermal limit, or approach is very different in that ts parameters are a basepoint of reference and then only used to verify QC.

 

[(The Other) Colin Miller]

Put a linkwitz transform on that sucka and stop worrying about it. Dial in whatever Q you want.

Chris

Thanks for the suggestion.

I've heard reference of this many times, though I haven't run across anything that specifically defines exactly how it is applied.

I understand, I think, the basic concept, in that if you apply minimum phase EQ directly to a signal feeding a minimum phase device to correct the amplitude for the Q that you want, the phase will follow.

My DSP units allow me to adjust the Q/shape of the shelving filters, such that the shape of the shelf can compliment/compensate for the 'hump' before roll off. I stumbled upon that as opposed to simply dinking with parametric peaking/cut filters while twiddling on another project. Using that, I've managed to extend the low frequency response while still keeping the slope and the shape about the same, mas o menos.

However, the 'Q' values the units reference in terms of the parameters don't seem to reflect the same conventions reflected by the TS parameters. Rather, the numbers applied reference the bandwidth of the filter in 'octaves'. I can replicate (or get pretty close to) a 2nd order butterworth by simply adjusting for maximally flat and 3 dB down at the crossover point, and a 4th order L/R by cascading two of them and verifying that they're 6 dB down at the crossover point. That seems to work pretty well, though it's a lot of try and see, then try again, repeat until better.


* Edit, after homeworking on the Internet*

ESP - The Linkwitz Transform Circuit

ESP - The Audio Pages. A complete description of the Linkwitz Transform Circuit - find out how it works.

www.sound-au.com

It looks like a Linkwitz transform is basically applying shelving filter with a complimentary shape to effect the curve you're looking for. Maybe I've been unwittingly fancy (or at least partially fancy) earlier than I knew?

Is there more to it than, or is this at least 'close enough for government work', for those of us not inclined to step into some deep math?