[Kevin Haskins]

I am now stocking and selling both the Velodyne SMS-1 & SC-1250 power amps.    Both are great tools and additions for the subwoofer lineup.   I'm getting some measurements on the SC-1250's pre-configured equalization curves and hopefully will have some suggestions for subwoofer builds that match.

With the purchase of an Exodus Subwoofer the SMS-1 is $525 plus shipping.

With the purchase of an Exodus Subwoofer the SC-1250 is $900 plus shipping.

Give me a call if you want to purchase otherwise.

Best,
Kevin

[Kevin Haskins]

I have the SMS-1 up on the site.   I'll work on the web site this week to offer some packages with the Exodus subs, discounting the package.

Let me know if you see any typos.




http://www.diycable.com/main/product_info.php?products_id=687


I'll also be getting some measurements of the SC-1250, 1000W Class D amplifier along with an Auto-EQ DSP system.    Velodyne uses some pre-equalized settings for their contractor series subwoofers and I'm hoping to take advantage of a few of those configurations.   

[Kevin Haskins]

And here is the SC-1250 contractor series amplifier.

I'll take some FR measurements of the various EQ curves for those who want to know.   I am looking for a couple that may be of use with Exodus subwoofer builds.



And the rear panel.



http://www.diycable.com/main/product_info.php?products_id=688

[Kevin Haskins]

Ok... I took some measurements of the SC-1250 and it's various pre-set modes last night before heading home.


Here is the frequency response in generic mode (no equalization applied).   Notice it has a little 3-4 dB hump centered on 24Hz.   I assume this is due to a highish Q subsonic filter in the analog domain and maybe some help with a DSP filter because it is fairly aggressive.    Either way, it isn't anything more than a curiosity due to the fact that the DSP equalization is going to deal with the in-room measurement, making the hump in the FR moot to some extent.    The subsonic filter is a good thing as far as I'm concerned.   It allows us to use this beast on resonant systems, specifically the Maelstrom-X plus Passive Radiators and provides good protection for the driver.



The above was without any kind of low-pass filter.    You can see once again, there is some sort of low order roll-off up high.   The output filter on the output stage of the Class D amplifier was probably intentionally designed for this limited bandwidth application.   

Here it is with the DSP based crossover @ 160Hz.



Same measurement with the low-pass @ 80Hz.   Ignore the jaggies in the measurement above 150Hz, they are a limitation of the measurement, not representative of amplifier behavior.   



And here is a 30Hz (lowest setting).   Once again ignore the jaggies. 




I took measurements of all the pre-set equalization curves.   They are not really going to be useful due to the fact that Velodyne uses limiting filters to protect the subs.   I could design something that would work with my subs but the limiting filters would in effect neuter the output, not taking advantage of our high stroke designs.    I'll try a sample at some point to confirm. 

[Kevin Haskins]

I also measured the Parts Express 1000W rack-mount subwoofer amp.    This one also has a subsonic filter with a corner they say is at 17Hz.

Here is the raw FR without any filters applied (besides the subsonic).   There is with the onboard signal processing bypassed.   As you can see, it is still a limited bandwidth amplifier.   Nothing wrong with that, that is it's design intent.   



Here it is with the low-pass filter set all the way to 200Hz.   I think the little hump at 50Hz is due to the PEQ.   It is hard to dial it in so that it doesn't have any effect on the response.   My biggest beef with these types of controls is that the knobs only approximate the settings.   You would really need a room measurement to meaningfully set them.   



Same thing, 100Hz low-pass.



And the lowest setting, 30Hz.



Here is a measurement using the PEQ settings at a 65hz setting, full cut (about 15dB) and a Q of about 0.2.    You can see the circuit works well, but you would need a way to measure the in-room response, set the controls, retest, twiddle the control, retest, twiddle the control, retest, twiddle control etc... etc...      Do this a couple times and you quickly find the value of the Velodyne setup that gives you a quick room measurement, and allows you to view the response and quickly equalize (with seven PEQ filters rather than one).     

[JDUBS]

Kevin, that SC-1250 looks like an awesome subwoofer amp!  I know it mentions a maximum of two subs, but is this driven more by the 4-ohm total load?  Just curious if you could run >2 subs such that its a 4-ohm load or better.

-Jim

[Kevin Haskins]

Kevin, that SC-1250 looks like an awesome subwoofer amp!  I know it mentions a maximum of two subs, but is this driven more by the 4-ohm total load?  Just curious if you could run >2 subs such that its a 4-ohm load or better.

-Jim

Jim,

Yea... ignore the two subs comments in the marketing materials.   All of the contractor series subs that Velodyne designed for the installer market are 8-ohm subs.    This is a single amplifier channel that is designed to run a 4-8 Ohm load.    If you have two subs in different locations you are going to need two different equalization curves.    It doesn't have the ability to individually measure a sub and set equalization differently for two subs.     The only time it would work, is if you built the two drivers into one enclosure and had them physically in the same subwoofer/location. 

It is a good amp for a Maelstrom-X as it packs enough power.    It has more than enough power for either a single Shiva or Tempest.   

[JDUBS]

Kevin, that SC-1250 looks like an awesome subwoofer amp!  I know it mentions a maximum of two subs, but is this driven more by the 4-ohm total load?  Just curious if you could run >2 subs such that its a 4-ohm load or better.

-Jim

Jim,

Yea... ignore the two subs comments in the marketing materials.   All of the contractor series subs that Velodyne designed for the installer market are 8-ohm subs.    This is a single amplifier channel that is designed to run a 4-8 Ohm load.    If you have two subs in different locations you are going to need two different equalization curves.    It doesn't have the ability to individually measure a sub and set equalization differently for two subs.     The only time it would work, is if you built the two drivers into one enclosure and had them physically in the same subwoofer/location. 

It is a good amp for a Maelstrom-X as it packs enough power.    It has more than enough power for either a single Shiva or Tempest.   

Cool.  Thanks Kevin.  Very nice looking amp!

-Jim

[Kevin Haskins]

Ok... I'm not allowed to have them on the site due to Velodyne Internet policy.    I can sell them, just not offer them for sale individually via the shopping cart. 

I'll have some packages that include them with the subs, otherwise you will need to call to order.