TOPIC:

Hi!

I have a 2X4HD, and I've run the REW correction and love it!

I'm considering taking the plunge for the DDRC-24 upgrade, and I have a few questions:

1) My speakers are rated to 32Hz, and I'd like to extend the range just a bit to maybe 27Hz - but no subwoofer. When I read about the functions, it appears that the system is intended toward a "real" 2.1 system. (I know that my 27Hz will not be as "genuine" as 27Hz if I had a true subwoofer, and that's okay). Any issues extending the bass that deep? (Maybe a +6-8dB boost will be needed in that range)

2) It seems like I will lose my PEQ abilities, to further "tweak" the sound according to my own listening preference. How adjustable is the target curve? I like to make a few narrow "bumps" with the treble frequencies. (I don't mind digging out my old graphic EQ for this task if necessary but it would be nice to stay keep it all within the MiniDSP).

3) On my 2X4HD I use outputs 3 and 4 to go to a 2nd amplifier for L&R to a different room(zone), with its own REW correction. Will I maintain the ability to separately handle the 3rd and 4th full-range outputs, or will the DDRC-24 only send subwoofer outputs to channels 3 & 4? (I would even be happy with non-corrected L&R outputs to channels 3&4 if necessary)

Thanks!

-Bob C.

Hi, the potential negative effect of bass boost will be the same regardless of how you get there. I'd suggest trying it with the PEQ and see. Personally, I would not be trying to boost the speaker if it's ported (unless it's quite large and you don't listen very loud).

The target curve is "quite" adjustable. It won't do notches I don't think. Not entirely sure what you are after but you can try the free download from dirac.se.

Re. 3rd question, please see manual

Thanks John-

1) When you say "the potential negative effect of bass boost" - I'm not going to ask the speakers to do anything I haven't heard them do already. They make great sound down low (and yes they are big speakers that I typically listen at a low volume). I infer from your statement that there is an issue with over-boosting the bass, although it sounds like you are saying it would be a speaker issue and not a miniDSP issue (?). I'd love to learn more about that statement...

3) According to the manual, it seems like the input PEQ I have now would be replaced with the Dirac parameters. Right now, I have my room correction parameters on the output of channels 1&2, and the input parameters are just my personal "flavor" of the music. After the Dirac room correction is run, could I manually move those parameters (I assume just copy the biquad parameters) to the output channels (outputs 1&2) since I only have two speakers in the room? Then I can leave my old-fashioned REW correction on output channels 3 & 4? This would leave my input PEQ to be according to my "taste".

(Being a licensed piece of software, I realize that I may be locked out from reading the data that the Dirac routine generates... which would make #3 impossible)

If that doesn't make sense, let me know and I can try to clarify.

Thanks!

-Bob C.
Edit: Regarding point #1, I added a thumbnail of a screen capture I took from another forum - not sure about the rules but I can make an attribution if necessary (or even delete since I didn't specifically request permission from the originator). The screenshot shows the Dirac correction that someone else got with the identical speakers as mine, and he seems to have been able to successfully "extend" his bass down to about 24Hz, which would be more than enough to make me happy. (He was using a DDRC88A)

Hi Bob!

I agree with John. From my experience, I would not extend very much the low end response of the loudspeakers. Taking the example of your graph (just in my opinion) it would be safer (and would sound pretty well) to adapt the target curve to the natural roll off of the speakers. I read an in-room response of -6 dB nearly 24 Hz, which is just excellent.

The drawback of extending the low end response is that you are working against physics. You would give the drivers to more excursion (more critical in bass reflex designs, as John noticed) and even get little acoustic benefit. Try the Dirac Live demo and play yourself.

Hope I have helped!
Jorge

Thanks for the feedback...

I know the speakers can make the sounds I want them to make. I don't know whether that is 32Hz or 26Hz or what, but the speakers can make the sound at the volumes I listen. My concern isn't the speakers. I'm not asking them to do +30dB at 13 Hz - I'm just asking them to make sounds I've already heard them make.

Is there a reason the 2X4HD has a problem in that frequency range? It seemed to work fine for the other gentleman on the DDRC-88A, but I haven't looked at the processor or whatnot to see if that has some different capability than my 2X4HD. And I've heard my own speakers do just fine down there when "boosted" (not a very good word, I realize) down in that frequency range.

It seems that I have set off some alarms here, and I'm not sure why. I know my 27Hz will not be as good as 27Hz produced by a large Hsu or SVS, but when I've gone that deep before with these speakers I've been very happy with the sound. As a matter of fact it's the reason I gave away my SVS (SB1000) - because I found the speakers making all of the bass I need in the range that I want, which is already on the border of having the upstairs neighbor complaining at pretty low volumes.

Not trying to argue - just trying to learn. I've heard the sound I like, and it seems like someone else has even more success than I've had (per the graph) - but I'm being told that I can't do it. It's a smart group here and I just want to learn more!

Thanks,

-Bob C.

The excursion of a ported loudspeaker increases very rapidly below the port tuning frequency. Boosting at these frequencies will increase that excursion even further, which is why caution is warranted. However, if they sound fine to you then they are, in fact, most likely fine.

There are no alarms, just information in response to your question...

On your other question, you can generate filters with different target curves to save in the (four) preset configs. Or if you want to change things "on the fly" then you can change the PEQs in the output channels. (Does that help? )

All of these concerns/warnings are only related to the loudspeaker capabilities (size, sealed/ported, tuning frequency) and room interaction (room boosting or reduction), lets say the electro-mechanical and acoustic domains. None related to dsp capabilities or quality. Any of the Minidsp processors will do a great, great job there. The choice will depend mainly on your connectivity and system integration possibilities.

Regarding boosting: just remember that each +10 dB = x10 W (power); +20 dB = x100 W; +30 dB = x1000 W

As John said, try by yourself and know your system's limits. It is quite easy!

Jorge

Thanks! Makes sense. I can handle the "aural" part of it - like I said it's all sounds I've heard the speakers make before. Haven't measured it, but I'll know it when I hear it. I will probably tune the Dirac with a flat target curve and then play around with the output PEQ settings to suit my taste in bass and make sure I'm not doing wonky things with the speakers.

And with regards to the output channels - I understand what you say, thanks for the information. However it looks like room correction (which I'll perform in the living room) will also be applied to output channels 3 & 4 even though those speakers are in room #2 and have totally different characteristics. Ideally I would have liked the room correction to be applied on the output side for only channels 1&2, but I'll deal with it!

Thanks again for the help!

-Bob C.

If you want to, you can perform the calibration for Room A, store it in one preset, then perform calibration for Room B and store that in a different preset.

There are only 2 channels of DL correction in the DDRC-24. If you want more channels of DL at the same time, you will need the DDRC-88A, and there's an app note for that.

HTH

Hi-

Just wanted to follow up...

I got the upgrade, and I've been playing around with it. Holy smokes! What a great setup.

FYI after I ran the measurements, the Dirac software suggested a correction down to 18 Hz. My chin almost hit the floor when I saw that! But sure enough, the system produces bass unlike I've ever heard from just a pair of floorstandiing speakers. Then I kept playing around with the PEQ settings, and I'm completely blown away. I had to back the settings WAY down from where it would tolerate - it just overpowered me and made me borderline uncomfortable (and I'm sure the neighbors weren't fans). In fact I couldn't even find the limit of the system, for fear of the entire building getting upset with me. I sit here listening to the system and I can't believe that there is no subwoofer in the room. And LFE in movies are, well, beyond what I thought this system would ever do or want.

And needless to say - the rest of the room correction sounds fantastic as well. The "dark room" test (lights off, to visualize the band/artist/etc. playing in front of you) is just out of this world.

Target achieved.

-Bob C.

Fantastic! Thank you for the update