[rythmik]

Very cool!  Have you been using Hypex amps in the other plate amps too? 

All HX* amps from our nomenclature are based on Hypex Ucd modules.  Our finished sub LV12R is based on Ucd module and we have been selling them for 9 months now. We almost sold out the first batch and arranging a second batch. 

Each Ucd module is most cost-effective when seeing a 4ohm load. That is what we are shooting for.  It also helps us the standardize the load. We use to have 8ohm version of 12" and 15" drivers, we stop them a while ago in favor standard 4ohm drivers. But 8" driver seems to bring back the old problem again for a different reason. Some may want to simply the crossover and put four 8" driver in each channel (like two in fornt and two on the back).

Now I'm confused.  I'd like to add an 8" sealed sub to a set of X-LS classics for a computer setup.  A single 8" driver seems like an excellent, compact option.  Which amp would I need to pair with which driver?  HX580 w/ 4 Ohm driver and leaving one amp unused?  Are there any plans for a sealed enclosure w/ a single 8" driver?

Here is a photo of what I have for my prototype. It is 12" wide, 20" high, and 14" deep. The white dots on the dust cover are my markers, not something you will see from production units. With two 8" driver, its output is very comparable (albeit a bit less) to a typical DS1200 or SW12-04 driver.



This is the close-mic frequency response of prototype. The final production will be a bit different. This should give you some idea of the frequency response.  Note that this is close-mic, if one consider baffle loss in real application, the upper will be slightly emphasized and that makes the upper end extension a bit higher than this plot.  Objective of these 8" subs to simplify crossover design. I have seen some advocating MBM. In my view, MBM just adds crossover complexity. If we can have enough number of these smaller driver, at the same time, provide sufficient low end extension, it should be a better alternative. 

We recommend to have the driver fully populated.  Ucd is self oscillation class-D. If you don't put a load, the output can see a high DC. I am not sure how that is going to affect long term reliability.

Has a price been set for the amplifiers intended for the 8" (sealed box) speakers? And can you point me to the specs on them (or a verbal description)?  Also is the cost of all the 8" speakers the same as the 16 ohm 8" OB version?
 
Thanks

Sealed version of 8" driver (DS800) will be $139 each list price (a bit more expensive) than Danny's SW08 drivers.  HX580 (we should have name these HX600, but we already have a model H600, so we name the amp HX580 to avoid confusion) has list price of $379, and HX300 has a list price of $289. Please note each HX amp is a mono amp regardless how many Ucd modules it uses.

We do encourage the customers to use a pair of HX580 driving four DS800, we have a package price of $1179 for that. 

[jparkhur]

Here are the images of the 8" in an OB application.  Danny and Brian did a nice job on these.  I had to use the 370 amp at the time, the others were not in yet. 

[rak313]

...



Here is a photo of what I have for my prototype. It is 12" wide, 20" high, and 14" deep. The white dots on the dust cover are my markers, not something you will see from production units. With two 8" driver, its output is very comparable (albeit a bit less) to a typical DS1200 or SW12-04 driver.

That looks like a 1.4 cu. ft. box for 2 x 8" drivers. I thought Danny said the 8" driver only needed 0.35 cu/ ft per driver?

...
We recommend to have the driver fully populated.  Ucd is self oscillation class-D. If you don't put a load, the output can see a high DC. I am not sure how that is going to affect long term reliability.

Couldn't you short the unused amp's input , and wire the output to a 100 ohm 10W resister?

...
We do encourage the customers to use a pair of HX580 driving four DS800, we have a package price of $1179 for that. 

Just to be clear - you mean 2 x HX580 (4 total amplifiers) with each amp driving a 4 ohm 8" speaker? and how much cu ft per driver?

Thanks

[AKLegal]

So if  I want to build a dual 8" open baffle sub I need to buy the HX300 amp correct?  Also, since Danny's subs are 16 ohm, a OB with two of them in parallel would see about 150 watts from the HX300 right?

[jparkhur]

So if  I want to build a dual 8" open baffle sub I need to buy the HX300 amp correct?  Also, since Danny's subs are 16 ohm, a OB with two of them in parallel would see about 150 watts from the HX300 right?

You can do three without issue.   16 + 16 + 16 would be 5. 3 ohms.  (feel free to tell me I am off?)



Danny says....

Actually the DCR is less and three of the woofers comes in right at 4 ohms.

[AKLegal]

You can do three without issue.   16 + 16 + 16 would be 5. 3 ohms.  (feel free to tell me I am off?)

I think that is right, if not I need a refresher course.

What are the dimensions to the U-Frame you built?  How low do three 8s go in that configuration as opposed to the h-frame?  I'd prefer to build a u-frame as its easier to build and looks better imo.  Thanks

[rythmik]

So if  I want to build a dual 8" open baffle sub I need to buy the HX300 amp correct?  Also, since Danny's subs are 16 ohm, a OB with two of them in parallel would see about 150 watts from the HX300 right?

OB drivers are in a separate category because the power they receive is not used to fight back the back pressure of sealed enclosure. The 200-300WRMS per driver is more for sealed configuration.

[jparkhur]

OB drivers are in a separate category because the power they receive is not used to fight back the back pressure of sealed enclosure. The 200-300WRMS per driver is more for sealed configuration.

This makes sense.. Thanks Brian..

I think that is right, if not I need a refresher course.

What are the dimensions to the U-Frame you built?  How low do three 8s go in that configuration as opposed to the h-frame?  I'd prefer to build a u-frame as its easier to build and looks better imo.  Thanks

Don't remember...  You could probably figure it out pretty close by the photos.  Danny stated that you could increase the sides some to make them go lower.. but not over 4-5 inches total.. then problems occur.
I know there is a 3 degree tilt and the tweeter / FRD mid point is at 37 inches

[Danny Richie]

You can do three without issue.   16 + 16 + 16 would be 5. 3 ohms.  (feel free to tell me I am off?)

Actually the DCR is less and three of the woofers comes in right at 4 ohms.

[rythmik]

That looks like a 1.4 cu. ft. box for 2 x 8" drivers. I thought Danny said the 8" driver only needed 0.35 cu/ ft per driver?

The Vas of the driver is 25liters. So larger enclosure can see more output at 10hz (about 3/4" peak to peak excursion).  If you don't need output at 10hz, you can settle with smaller enclosure size. Our extension filter switch now has 3 settings: 1) Low/music, 2) Low/HT, and 3) high. At low/music, it is a simple 2nd order extension filter at around 18hz with Bessel alignment which mimics a typical sealed sub roll-off.  For Low/HT, a 3rd order rumble filter is added.  For High extension, we use a 3rd order filter at 28hz.  If the customers use a smaller enclosure, we will recommend either 2) or 3) setting.

Just to be clear, our design objective is try to extend the low end as much as possible so the customers can hear what a "fuller spectrum reproduction" can bring us.  If we want to do that, we need to also be able to produce SPL at a reason level, and hence the enclosure size consideration.  I am very happy with the proto-type. I play "Peom of Chinese Drums". I can almost feel the vibration of the drum skin. It sounds very open/transparent/effortless. When you put the driver into a enclosure too small, it will begin to sound compressed. For these 8", I really haven't tried when that will happen. As more clients/customers try them out, we will get a better picture of the best trade-off. 

Just to be clear - you mean 2 x HX580 (4 total amplifiers) with each amp driving a 4 ohm 8" speaker? and how much cu ft per driver?
Thanks

Hope the above explains the trade-off of using large vs smaller enclosure volume. This weekend, I will put in a wood block into the enclosure to reduce the volume and see how it affects the low end output. My experience is at 20% variation is not going to cause the world to collaps, so 0.7*0.8=0.56 is probably also ok. Anything smaller should wait till our further investigation.

[brj]

So is the HX300 suitable for a single 12" sealed SW12-4 driver?

Is it available now?

Thanks!

[rythmik]

So is the HX300 suitable for a single 12" sealed SW12-4 driver?

Is it available now?

Thanks!

It is not.  Crossover and phase adjustment in HX300/HX580 has been designed to be more suitable for higher crossover frequency.  If you'd like to save money, we still have some A300 left.  Those work well for SW12-4.

[sts9fan]

That dual 8" will be a product? When?

[AKLegal]

^^^

Anyone who are interested should send me email as soon as possible as I am arranging air-ship units and i need a tally of how many units to airship.

Has anyone gotten a response from Brian regarding the above?  I have emailed him and sent him a PM but he hasn't responded.

[kc8apf]

I haven't had a response either.

[rak313]

Brian,

Do you have T/S parameters for the  8" - 4 ohm driver?

Thanks
 

[Greggo]

At some point, it would be great to just get a clean list of recommended woofer/amp combinations for both 8" and 12" for both sealed and OB.  I find both the GR Research and Rythmik Audio sites to be a little confusing as to how to quickly find the right pairing between amps and drivers for the desired application.  I am hoping to launch into a big DIY project by next summer, and right now the GR servo subs are at the top of my list for handling 20-250 Hz.  Intrigued by the idea of 4 x 8 inch woofers per side, but probably land on 2 x 8 inch plus amp for each side.  Probably going to do an 8 inch mid plus waveguide passive design and then figure out how to put a circuit in front of the main power amp to roll things off to line up with the servos at 250 Hz.

Do the new amps offer a line out or do I need to split my pre out into two rca cables for each channel, one feeding a servo amp and the other feeding my main amp?

Regards,

Greg Jensen

[Danny Richie]

Intrigued by the idea of 4 x 8 inch woofers per side, but probably land on 2 x 8 inch plus amp for each side.  Probably going to do an 8 inch mid plus waveguide passive design and then figure out how to put a circuit in front of the main power amp to roll things off to line up with the servos at 250 Hz.

Sounds like some stuff that I am working on.

Do the new amps offer a line out or do I need to split my pre out into two rca cables for each channel, one feeding a servo amp and the other feeding my main amp?

The best thing to do is split the signal at the pre-amp or at your power amp. I have been using the inline RCA filters that I am making for Serenity Acoustics and those work out great.

[jtwrace]

All HX* amps from our nomenclature are based on Hypex Ucd modules.  Our finished sub LV12R is based on Ucd module and we have been selling them for 9 months now. We almost sold out the first batch and arranging a second batch. 

Do you think you will ever switch the A370 series to have the UcD module? 

[rak313]

I would think the N3s (vertical version) combined with an single sealed 8" servo would be compact and sound mighty good as a small set of mains.