Simple 12" Infinity Kappa VQ MidQ Plans

[WmAx]

I found some nice Neutrik XLR to RCA adapters at mouser for 8 bucks a peice so i got a couple of those. So far everything is on order except the amplifier which I am hopefully getting used. Going to head to lowes or home deeps and see what they have for plywood or MDF, I may just go with the MDF anyway if its much cheaper.

Realize that while you can convert from RCA to the input of the DCX, if you go from the DCX output to a RCA consumer level input, the DCX may over-drive the regular amp and have a slight audible hiss(due to the very high level being send to the consumer level input). A Harrison Labs 12dB attenuator can be use in line to the consumer amp, if you intend to send a signal to a consumer amp. Or you can get a transformer based passive convertor that will reduce the voltage and prevent ground loops at the same time. This is just a warning if you try to send DCX output to a consumer level amplifier.

-Chris

 

[Haoleb]

Realize that while you can convert from RCA to the input of the DCX, if you go from the DCX output to a RCA consumer level input, the DCX may over-drive the regular amp and have a slight audible hiss(due to the very high level being send to the consumer level input). A Harrison Labs 12dB attenuator can be use in line to the consumer amp, if you intend to send a signal to a consumer amp. Or you can get a transformer based passive convertor that will reduce the voltage and prevent ground loops at the same time. This is just a warning if you try to send DCX output to a consumer level amplifier.

-Chris

Thanks, I'll be using the EP2500 and I'll just make or pick up a short set of XLR to XLR for that.

I just downloaded the Room EQ wizard software, I already have the RS analog meter and a couple denon room setup mics that i found laying around at my old job, One of them is quite nice. I dont know how well it performs though.

I'll have to download the DCX software and check it out

 

[WmAx]

Thanks, I'll be using the EP2500 and I'll just make or pick up a short set of XLR to XLR for that.

I just downloaded the Room EQ wizard software, I already have the RS analog meter and a couple denon room setup mics that i found laying around at my old job, One of them is quite nice. I dont know how well it performs though.

I'll have to download the DCX software and check it out

BTW, I do hope you will use an outboard amp for the mains and use the DCX to control those as well. In that way, you can achieve seamless/perfect integration, along with multiple ways to adjust tonality of your mains, especially if you measure them with an accurate measurement mic to determine issues that can be addressed.

-Chris

 

[Haoleb]

At this point I doubt i'll be doing that, I may give it a try at some point but as it stands now I have no plans to. This is strictly a 2 channel system, no recievers no eq's none of that. Of course I am open to trying something that will improve the sound though.

As a side note I just got back from lowes and picked up two sheets of 3/4 birch ply ($55 each here) I'm going to rip all the peices for both cabinets today and probably start gluing the internals up ive only got enough clamps to do a couple peices at a tiime so it will take a couple days for me to get it all assembled and then design a more attractive way to mount the driver vs just screwing it on the front. I might flush mount it. Have to see what I have to work with when they show up.

I'll be taking plenty of pics along the way too

 

[avaserfi]

At this point I doubt i'll be doing that, I may give it a try at some point but as it stands now I have no plans to. This is strictly a 2 channel system, no recievers no eq's none of that. Of course I am open to trying something that will improve the sound though.

As a side note I just got back from lowes and picked up two sheets of 3/4 birch ply ($55 each here) I'm going to rip all the peices for both cabinets today and probably start gluing the internals up ive only got enough clamps to do a couple peices at a tiime so it will take a couple days for me to get it all assembled and then design a more attractive way to mount the driver vs just screwing it on the front. I might flush mount it. Have to see what I have to work with when they show up.

I'll be taking plenty of pics along the way too

Using a high quality equalizer such as the DCX2496 will allow for optimal performance of your loudspeakers if they are sufficiently linear. This is due to the equalizers ability to form virtually any desired tonality.

Also, if you plan on flush mounting the driver you will need to laminate to 3/4" pieces of ply together on the front baffle otherwise the ply is just not thick enough.

 

[WmAx]

At this point I doubt i'll be doing that, I may give it a try at some point but as it stands now I have no plans to. This is strictly a 2 channel system, no recievers no eq's none of that. Of course I am open to trying something that will improve the sound though.

If it's stand alone 2 channel system, then you have an outboard amp for the mains, right? Get a xlr-rca transformer adapter and route the DCX to the mains amp and use the DCX to process the signal. It will be the IDEAL set up that offers the highest sound quality, lowest distortion, etc.

-Chris

 

[Guiria]

You will want to get some OC705 or 8lb Rock wool to place inside the cabinet. Use a 4" piece wrapped in cloth (to eliminate chances of pieces being blown out the port) and glue it (using 3m Spray 77) to the large brace.

To clarify...

Cut a piece of 4" thick rock wool the size of the large brace and glue it to the front of the brace so the damping material is between the brace and the back of the driver?

This build plan looks awesome, thanks for your hard work.

 

[avaserfi]

To clarify...

Cut a piece of 4" thick rock wool the size of the large brace and glue it to the front of the brace so the damping material is between the brace and the back of the driver?

This build plan looks awesome, thanks for your hard work.

Well, the rock wool only comes in 2" sections as far as I know. So you would need to laminate two pieces together. Otherwise you are correct. You can also place some on the bottom of the cabinet. As long as it has about 4" distance from the port opening (top of cabinet) you are okay.

 

[mike c]

WmAx,
i'm considering the DCX2496 over the DCX2310 for simple crossover work, because it would seem that the 2496 has more accurate crossover cutoffs due to it being digital.

i have a question though about the unit and all behringer units ... they all seem to have specs/feature uses only up to 20hz, has there been a measurement on Behringer units on how they behave below 20hz?

 

[WmAx]

WmAx,
i'm considering the DCX2496 over the DCX2310 for simple crossover work, because it would seem that the 2496 has more accurate crossover cutoffs due to it being digital.

Yes, the DCX is deadly precise. I have measured it's response actual vs. indicated response. Here is a comparison of the GUI's EQ response as indicated on the adjustment window vs. actual measured response: http://www.linaeum.com/images/dcxaccuracy.gif

i have a question though about the unit and all behringer units ... they all seem to have specs/feature uses only up to 20hz, has there been a measurement on Behringer units on how they behave below 20hz?

The 20Hz limit is the lowest value where you can specify a filter. It is not a bandwidth or frequency response limitation on the DCX. The engineers decided to limit the lowest filter setting ability at 20Hz for some unknown reason. I am not sure what the FR is on the analog CX units.

-Chris

 

[ParadigmDawg]

Ok guys, I am pretty certain that I am going to sale the Servo and try a couple of these. Any downside to this plan?

 

[WmAx]

Ok guys, I am pretty certain that I am going to sale the Servo and try a couple of these. Any downside to this plan?

Let's see....

1. Far superior performance...

2. You get a valuable learning experience...

3. Lower cost than a commercial sub of far lower quality...

I can't seem to find the negatives......

Oh, wait.... there is no warranty on your own built product. Is that a problem?

-Chris

 

[ParadigmDawg]

Cancel the "valuable learning experience", you know who will be doing the dirty work.

Let's see....

1. Far superior performance...

2. You get a valuable learning experience...

3. Lower cost than a commercial sub of far lower quality...

I can't seem to find the negatives......

Oh, wait.... there is no warranty on your own built product. Is that a problem?

-Chris

 

[jboogie]

A million thanks

I will be starting my build of these starting on Wed. I am going to integrate a plate amp, but that should have minimal effect on the overall plan.

(For those that saw some of my other ?'s and replies, I have decided to keep the plate amp and simply upgrade at a later time.)

I will post with any progress or insights.

Again, thank you so much!

 

[Haoleb]

Where are you going to mount the plate amp? There is little room inside the sub for something like that. If you put it on the back you'll be blocking the airflow in the port (depending on how deep it is)

 

[WmAx]

DO NOT INSTALL the plate amp in any part of a port wall.

-Chris

 

[Djizasse]

I've seen this on sale:
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&ssPageName=STRK:MEWAX:IT&item=370065635446

It refers to the "INFINITY KAPPA SERIES PERFECT 12D VQ" (notice the "D" after the 12).

I consulted the infinity site but was unable to understand the differences between the "12 VQ" and the "12D VQ" versions.

Is it still appropriate to this project?

 

[WmAx]

I've seen this on sale:
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&ssPageName=STRK:MEWAX:IT&item=370065635446

It refers to the "INFINITY KAPPA SERIES PERFECT 12D VQ" (notice the "D" after the 12).

I consulted the infinity site but was unable to understand the differences between the "12 VQ" and the "12D VQ" versions.

Is it still appropriate to this project?

The 'D' stands for dual-voice coil. The one that all of the cabinet designs is given for here is the single-voice coil version.

-Chris

 

[gus6464]

Not to hijack the thread, but if one wanted less extension (25Hz max) would it possible to put these drivers in a smaller sealed enclosure?

 

[avaserfi]

Not to hijack the thread, but if one wanted less extension (25Hz max) would it possible to put these drivers in a smaller sealed enclosure?

This would be possible with the correct driver/amplifier/cabinet integration. The largest loss with using a sealed cabinet would be increased distortion, maximum SPL and low frequency response. It is important to note that a driver capable of being equalized with minimal distortion down to 25Hz in a sealed cabinet will be very expensive.

A cheaper option would be designing a ported cabinet that uses utility port. That is the port is not sufficiently designed to eliminate port compression (so it is smaller), but compression will occur out of the intended passband due to tuning frequency and DCX integration.