miniDSP SHD integration

I think the easiest thing for you is going to be to put the miniDSP right before the sub. That’s where most of your bass issues will occur anyway, and miniDSP is pretty transparent, especially for subwoofers.

Plug the ports on the back of your main speakers, this will make integration easier and lower the distortion and bass output.

I’ve had a great deal of success with this alone.

If you wanted to take this 1 step further, put a capacitor in line with your amp. This will give you a 6 db/octave high pass filter. Use about 0.04uF for an 80 Hz high pass filter.

Of course, if you are experimenting, at each of these steps you’ll need to remeasure.

Almost forgot:  Seek out the AM Acoustics room mode simulator and try to keep your sub, speakers and listening location outside the lowest room modes.

Ok, to be clear you are talking keeping everything as is except connect the miniDSP to the sub out on my preamp, then to the sub to control low pass and subwoofer room control. 
Then use a pair of capacitors on the speaker out to control high pass, without room correction. Interesting!

There is also the Mini DSP Studio SHD. Streamer > Studio > DAC> preamp. You can then do Dirac live room correction. Contact Deer Creek Audio for guidance on this.

OP:  You read that correctly.  this is pretty much the way the great Floyd Toole recommends.  His point, and I agree with it, is why buy a certain pair of speakers you like the sound of and then try to EQ them to sound like somethig else? Except in the bass, where all sorts of nasties lurk.

To clarify:  I'm paraphrasing Toole's take on EQ, but the suggestions for plugging the ports and using a high pass filter on the mains is not part of his argument.

@erik_squires

Thank you. My ports are plugged. It was necessary when I added my preamp to flatten my bass response. A couple more questions. Would the SHD be overkill in this scenario and a lesser miniDSP do? Would I not just run my AVR room correction in home theater pass thru & adjust the subwoofer equalization manually?

I really do think the SHD is overkill for this, when the HD for $250 will work just fine. The SHD is really meant to be a full function streamer/preamp. 

If you must have Dirac the miniDSP DDRC-24 will add that capability ~ $500, but then you are going to put it in front of your amp.   This is not really a terrible idea either, but you are going to have another A/D, D/A conversion in between. 

Ordered the miniDSP HD from Amazon for sub management only. Arrives tomorrow. Thank you. 

Great!  Good luck.

Forgot to mention that you can build effective high pass filters for your amp with screw down RCA terminals, a little wire and some caps.   I suggest Cornell Dubilier for your starter film caps. Then if you like the high pass performance/speaker integration move up to some nice copper films from Parts Connexion.

@erik_squires 

Lately I have seen you mentioning plugging ports on the mains to help with bass control. Obviously you must be on the camp of those who don't think the speakers can be hurt by plugging the ports. Can you elaborate on that and how you actually plug them. Socks, straws, part or whole? Sorry for hijacking the thread.

Hey @baylinor - You can’t hurt speakers by plugging ports, but you are changing their behavior. The behavior when plugging any ported speaker is going to be rather similar. You raise the -3 dB point, but also dampen the response. That is, if there’s a peak at the low end, the peak will be reduced. This behavior may be beneficial in some cases. Some speaker makers go so far as to include foam plug for this reason. For instance, bookshelf speakers which you might want to put all the way up to a wall.

From an academic, absolutist perspective, plugging a port is not the same as making an ideal sealed speaker.  Generally, sealed cabinets should be somewhat smaller than their ported counterparts, so if this was an engineering exercise you'd build 2 different cabinets, one for sealed and one for ported use, but from a pragmatic approach, several speaker designers and my own experience shows this approach can be useful if you have too much bass or are integrating speakers with a subwoofer.  It will also reduce cone excursion and distortion, an especially valuable feature if adding a sub without a high-pass filter.

The only way to know if this is right for you is to try it. I’ve had one A’goner report their bass was best with 1 of the 2 speakers plugged. I imagine this achieved a half-way setting between the two options.

You can actually improve reliability because having a sealed cabinet reduces the amount of motion the driver makes below the port frequency. Below resonance, the port is basically just a great big hole. That is, the springiness of the air in the cabinet which helps to control the woofer motion vanishes. The cabinet might as well not even be there. The THX standard for satellite speakers was to use sealed cabinets, because when combined with high pass filters the combined response would match subwoofers ideally. This is not as good a solution as the THX specs, but it shows that when adding a sub this approach can be useful.

I recommend virgin alpaca socks... :) Definitely not anything crunchy. Nice clean socks wadded up tightly which you can still pull out works just fine. You also don’t have to fully pack the port, just seal the ends, so if you have a very deep port, say 6" long, you don’t have to stuff the whole thing. Just a tight sock on the opening to prevent air from moving in and out of the cabinet is fine.

Much appreciated. It's only my streaming that at times needs some taming of the bass which I do on my dual subs. I did try plugging the ports on the mains before with similar results but was worried about messing with the integrity of the mains. Your explanation is reassuring.

@baylinor if you find yourself adjusting bass levels for music too much you may have some resonances you can tame with EQ if not otherwise.

Some music may excite a room mode, which has you reaching for the volume control.

Check the AM Acoustics room mode simulator for help placing your speakers, then measure and consider bass traps and/or EQ if the problems are still pronounced.

My issue is strictly music related. I use my streamer almost entirely for electronic music and like to play it at 75 db, hence the overamplified bass issue. My vinyl and CDs collections have less than 5% electronic music and bass is perfect.

My measured frequency curves improve significantly by plugging my ports (I have 2 rear firing ports per speaker). My KEF R11’s came with soft sponge plugs for that purpose. 

They are plugged again since Eric convinced me it can't hurt the speakers. I listened to some heavy electronics on my streamer and had no need to adjust the subs to tame the bass. It's all good. Thanks @erik_squires.

Glad I could help you, @baylinor  - You seem to have proven the effects I was talking about, how well-balanced bass output makes it easier to switch music and still have excellent results.