Velodyne DD-18 Subwoofer Review

[Sheep]

I'm pretty sure 4x 10s won't give you the LF extension of a 15 or 18, the main thing you gain by multiplying subs is spl. You might find that a single 18 could give you equal or higher spl than 4x 10s along with more extension, someone correct me if I'm wrong. You really only need one DD to flatten room response, +/-3db is considered flat, and in most situations 1 DD can do that unless you have serious room issues that should be addressed with acoustical treatments.

When you add SPL, you can play lower, they go hand in hand. 4 DD10s would be fine for my room, but since they don't use bracing, I may consider something more cost effective.

SheepStar

 

[Sheep]

also, is it normal for sealed enclosures not to have batting inside? (or was it all removed)

it hurts to see a DD opened up like that ...

It does have batting, didn't you see it to the side of the enclosure?

SheepStar

 

[MACCA350]

When you add SPL, you can play lower, they go hand in hand. 4 DD10s would be fine for my room, but since they don't use bracing, I may consider something more cost effective.

SheepStar

They must be braced well enough or we'd have heard about the problems. Check out the clear DD10 not much space for more bracing

cheers

 

[mike c]

i think you only gain SPL when you colocate, right? when you intend to benefit from a smoother frequency response by putting the subs in different locations, don't you lose the SPL advantage?

 

[Sheep]

They must be braced well enough or we'd have heard about the problems. Check out the clear DD10 not much space for more bracing

cheers

That's a small enclosure. The walls on the DD-18 are much larger, which in tern makes them more prone to resonate.

What sound does a DD-18 make when you wrap on it's side? *Cheap* *Cheap* lol

SheepStar

 

[MACCA350]

That's a small enclosure. The walls on the DD-18 are much larger, which in tern makes them more prone to resonate.

Here's what Velodyne say

the cabinet has been engineered to eliminate resonance and create stability

Whether you believe they've done their homework or not is your choice, but they're one of the oldest subwoofer company in the world, so they must have learned a thing or two over the years.

I've never heard any sound coming from the box itself, although the wall next to it vibrates quite badly at certain Fq

cheers

 

[gene]

That's a small enclosure. The walls on the DD-18 are much larger, which in tern makes them more prone to resonate.

What sound does a DD-18 make when you wrap on it's side? *Cheap* *Cheap* lol

SheepStar

Try to tone down the ignorance for once please. There is more to subwoofer design than stuffing a bunch of unnecessary bracing or overstuffing into a box. I personally own 2 DD15s and although they don't sound as dead as other products I've compared them to when you knock on the side wall, the sub sounds excellent. I never detect any boomy or hollow signature to them and they integrate quite well into a room, even when seated within a few feet if you properly set them up.

 

[gene]

i think you only gain SPL when you colocate, right? when you intend to benefit from a smoother frequency response by putting the subs in different locations, don't you lose the SPL advantage?

You gain SPL either way but depending on how the subs play into the room it can be anywhere from up to 6dB gain or loss if you have acoustical cancellations.

Either way, if you want deeper extension in a large room, its best to go with multiple larger subs.

 

[MACCA350]

Gene, how long have you had the DD15's for?

cheers

 

[jaxvon]

That's a small enclosure. The walls on the DD-18 are much larger, which in tern makes them more prone to resonate.

What sound does a DD-18 make when you wrap on it's side? *Cheap* *Cheap* lol

SheepStar

Subwoofers don't need to be as heavily braced as midrange enclosures. As long as the panel resonance is above the passband, you're cool.

 

[Sheep]

Try to tone down the ignorance for once please. There is more to subwoofer design than stuffing a bunch of unnecessary bracing or overstuffing into a box. I personally own 2 DD15s and although they don't sound as dead as other products I've compared them to when you knock on the side wall, the sub sounds excellent. I never detect any boomy or hollow signature to them and they integrate quite well into a room, even when seated within a few feet if you properly set them up.

Just a joke, hence the sarcasm face.

But, if the enclosure isn't the deadest, would extra bracing allow you to use a lower Servo setting and thus have more headroom?

SheepStar

 

[MACCA350]

Just a joke, hence the sarcasm face.

But, if the enclosure isn't the deadest, would extra bracing allow you to use a lower Servo setting and thus have more headroom?

SheepStar

No, because the enclosure at the moment isn't adding any distortion to the driver output. If anything heavier bracing could possibly lessen the output because if there is any flex with the box at the moment more bracing would lessen flex and increase the back pressure in the box and the servo would force the amp to deliver a bit more power to counteract the force(although the amps have heaps of headroom already). Also there is very little difference between the lowest and highest servo setting as far as distortion and output go(1 = 3,500 sampling rate, 8 = 16,000 sampling rate)

cheers

 

[MarkS]

Extra Driver Pics

Hello Mike C

As/ request, here are some extra pics of the DD-18
driver. Quite the behemoth.

hey gene, may we request for close up pics of the driver?
maybe he has some saved or something.


the one side view pic in the review looks to be a marketing pic from velodyne. the DD-10 driver Bruce Hall held in his video interview looks to be more intimidating than this one ...

 

[Reorx]

Gene, or anybody else who has heard this sub...

How would you compare this sub to those offered by other companies.
ie: SVS and HSU?

 

[mike c]

Hello Mike C

As/ request, here are some extra pics of the DD-18
driver. Quite the behemoth.

thanks MarkS!

 

[MarkS]

I most likely might be wrong on this but, shouldn't there be two lines on this graph?

Hello Mike C

A dBr vs frequency curve represents a ratio between two curves.
In this case, the operand curves were the THD&N (dB spl) at Servo
setting 1 & 8, each measured with the sub set to max. output.

Sometimes this approach is referred to as "normalizing" one curve to
another or simply "normalization". Presenting data in this way generally
makes for easy visual interpretation where it comes to making
comparisons between curves. Essentially, the more similar the operand
curves are at any given frequency point, the closer to 0 will be the
resulting dBr value at the corresponding frequency point.

Referring to Graph 2b, at ~ 67 Hz the dBr value = 0. At this frequency
point the THD&N (dB spl) plots for Servo setting 1 & 8 curves were
identical. At around 40 Hz, however, dBr = +4, which means the THD&N
dB spl figure for the plot produced at Servo setting 1 (minimum
feedback) was about 4dB greater than that produced at Servo
setting 8 (max feedback).

 

[Sheep]

Gene, or anybody else who has heard this sub...

How would you compare this sub to those offered by other companies.
ie: SVS and HSU?

Didn't you read the disclaimer in the first post?

SheepStar

 

[billy p]

Didn't you read the disclaimer in the first post?

SheepStar

I don't think that was there from the outset, or was it.

 

[Sheep]

I don't think that was there from the outset, or was it.

It was, which is why this thread actually stayed on topic.... somewhat.

SheepStar

 

[MarkS]

Mark,

What did you think about the build quality when you took it apart? I was surprised to see wedges for support, no cross bracing, and excessive silicone inside the cabinet. I'm sure it doesn't effect sq, but for 5 large, I thought I'd find gold in that box.

Hello Buckeyefan 1

The cabinet itself is very sturdily constructed.
It appears they've used tongue-and-groove joinery,
well doused with (probably) an epoxy and sealed
liberally wherever appropriate. As well, they sealed
every remaining potential leak point in the
unit with either silicon caulk or some sort of epoxy,
eliminating any chance of the sort of wind noises
that plague many, many subs. Any stresses
generated by extreme internal pressure variations
(remember, we're talking about a sealed system here)
or driver-sourced panel vibrations are handled
by the DD-18 cabinet with ease.

There's more than 1 way to approach the panel
resonance issue! Where it comes to said resonances
you can isolate, you can damp or you can shift the
resonance spectrum around.

The approach taken by Velodyne is to build the
DD-18 cabinet with panels sporting a resonance
spectrum largely outside that span of audible
frequencies where the system would likely be
operating. So, no, we don't see all sorts of
unneeded, complex internal architecture, just
an approach that works beautifully. Incidentally,
bracing occupies internal volume, which,
if all else is to be held steady, would require
a larger cabinet - something to avoid in a business
where SAF can weigh heavily when it
comes time to making purchasing decisions.

The modest amount of box stuffing used by Velodyne was
shown in one of the graphics. (Image 4a, I believe).
I would estimate the box stuffing occupied ~ 25%
of the internal volume of the cabinet.

When judging build quality I'm looking at how well a
manufacturer actually built the specific design approach
they chose, not what design approaches (or features)
they didn't chose to use/incorporate. Velodyne
did a great job, incorporating build features I haven't
seen in any other sub I've yet reviewed for Audioholics.

Overall, where it comes to extraneous noise, the DD-18
is by far the quietest home-use system I've encountered
so far.

Best regards,

MarkS