Velodyne SMS-1 anybody tried one yet?

Have any of you guys tried the Velodyne SMS-1?

It's a room correction system that works with any subwoofer. It appears to cost about £550 here in the UK (a rip-off as usual - it can be had for $600 in the US).

It also has an 80Hz high-pass output so your main speakers can be relieved of bass duties altogether - I guess you need a pre-power setup for that or perhaps a single source system.

 

Haven't tried one, but I'd very much like to. Have you seen this review?

 

I have much experience with the Digital Drive line of subwoofers and it's software, which is identical to the software in de SMS-1. Works great and improves bass performance spectacularly.

I am the distributor for Velodyne in the Netherlands, so if you have any question, I should be able to answer them...

 

I do have some questions

I have a stereo setup with an integrated amplifier (no bass management).

Currently my main speakers operate down to 50 Hz (-3dB) and the sub covers 20 Hz to 40 Hz. There is a room peak at about 45 Hz which is quite noticeable and another at 85 - 90 Hz.

If I want to correct this with an SMS-1, am I correct in assuming that I would need to use the 80 Hz high pass output on the SMS-1 to feed a power amp to drive my main speakers. The SMS-1 would then correct room modes in the 20 Hz to 80 Hz range via the sub.

If so, then the most important question is: what is the quality of the signal coming from the 80 Hz high pass output? Will it degrade the sound from my main speakers? I ask this because the SMS-1 is full of digital electronics (including video) which could pollute the analogue signal if steps have not been taken by Velodyne to ensure that the 80 Hz high pass output remains clean.

 

I hear great things of this on the avtalk forum for Velodyne products. It's definitely on my shopping list and, while you may think the UK price is a bit high relative to US, it is not expenive on an absolute level for what it does and how well it does it IMO. You should try the Norwegian 25% VAT!

http://www.avtalk.co.uk/forum/index.php?t=thread&frm_id=8&rid=1678&SQ=1138291688

 

The use of the SMS-1 for AV is quite different to its use for stereo. In an AV setup, the AV amp will perform bass management and will be used to limit the low frequencies going to the main speakers so that these frequencies are handled by the sub. In a stereo setup you can't do it this way so, unless your main speakers response naturally falls off from say 80 Hz (Spendor S3 perhaps), you have to use the 80 Hz high pass output from the SMS-1 to feed a stereo power amp for the main speakers.

I can well believe that the SMS-1 is a pure delight to AV fans and every house should have one

I am however concerned about its audiophile credentials. How good is that 80 Hz high pass output? Will it compromise a high-end stereo system?

Is anyone out there using a Velodyne DD sub for high-end stereo? Are you using the 80 Hz high pass output and if so, with what results?

 

We have used Velodyne DD subs in some very high-end setups, where we have used them purely BELOW the response of the main system, running the mains full-range. No luck in correcting the response above that however... Many of the nasties in the response of the main system can be dealt with by placement of the speakers/listener or bass trapping.

An example below of a system where we used a DD-18 up till 60 Hz, to fill a major gap in the response at the listening position, making sure the boost (always tricky) did not result in extreme levels elsewhere in the room.

 

I use a DD12 sub and it is superb. I use sealed box loudspeakers (the excellent Merlin TSM-MX standmounts) and cross over about 45 hz in fill in mode.

I do not have a pre/power combo so I cannot tell you about the 80 hz high pass mode.

In all honestly, rather than go for an SMS I'd save up more and try to go for a s/h DD12 sub, ditching the REL.

 

How much do these (roughly) go for s/h?

 

Err, lots. £1500 would be a normal s/h price.

 

I have a pair of DD15's.

I don't use the internal equalization at all (I do EQ using other tools). You could put it like this: I don't use the SMS-1 that's built into the subs.

To my mind, the secret sauce of the Velodyne is their excellent servo controlled distortion performance.

You can take the SMS-1 "functionality" out of the DD series and still have a sub woofer with awesome performance...

What you cannot do (and this is really my point) is add the SMS-1 to a mediorce sub and turn it into something great...

The DD series of subs really are the dogs bollocks..

 

I wasn't expecting to create the ultimate sub out of my REL. I was just trying to investigate ways of curing my room boom without chucking out all the furniture in order to install bass traps.

Right now it looks like building a pair of dipole speakers might be the easier (and cheaper) option.

 

For all the hoopla about dipoles (and there are some advantages to their power response), they nevertheless output bass and if the "room boom" (aka. standing wave, mode etc) exists along the axis on which they do put out that bass you are potentially still screwed unless you have a great deal of flexibility with placement (of both the listening position and the speaker).

 

The room boom takes time to build up. The SMS or Behringer don't work in the time domain so they will be less than perfect but people in practice like what they do after having gone to reasonable lengths with positioning and room treatment. I don't think one can make a dogmatic statement in advance of you trying one if you are not satisfied with the preparatory steps mentioned.

 

You could keep the REL and daisychain it off the DD, so it would be equalized too; placed in a different part of the room it could help level the lumpy response you will still get in places other than where the equalization mic was placed

 

Linearizing the frequency domain will have a big influence on the time domain. They are in some ways interchangeable. Correct for RT60 and you get linear frequency response and vice versa.

 

You seem to be simultaneously confused about both how those boxes work and the duality of the frequency and time domains.

[Parametrric] Equalization works because room modes are minimum phase - which means you only need to linearize the frequency response (domain) to get the right time domain behaviour.

 

Yeah, what he says...

 

The daisychained sub does not get a corrected response. It just gets the same response the first sub gets, so BEFORE correction.

I would never advise using different subs, due to phase issues.

 

TB - Cheers for reminding me of this product. I remember knowing Velodyne were going to release it but had since forgotten about it and didn't know it was out. I'm curious about it too, for reasons similar to your own I believe (a dominent ~50Hz room mode). Not sure if it will be possible to get one on home demo to try but I'd be very interested in giving one of these a shot sometime.

I'm not sure if the Velodyne does its measurements using a series of tones or using a frequency sweep, but I'd always assumed either the tone played long enough, or the sweep was slow enough, that time enough were provided for modes to build up? Certainly if I play a frequency sweep track I have through my system room modes are obvious.