Low Shelf Filter for Audirvana

Yes, you can access Audio Units from within Audirvana where you can add a parametric EQ. If you're fairly sure it's 45Hz, you should be able to configure the centre frequency at 45Hz and specify the amount of attenuation to apply and the width of the attenuation curve. I'd start with an attenuation setting of -3db and a Q of about 12 (that's the Q value that sounds about right for me in a room with a strong 49Hz resonance. Then try increasing or decreasing the attenuation in 1db steps until the booming seems under control, then maybe 0.5db steps around that point. Live with that for a while (few days), then maybe tweak the attenuation again after becoming acclimatised to the 'new' sound.

thanks allan. i tried it last night but it seemed to kill the nice instrument timbres and sound i was getting. perhaps a bettr quality plugin\audio unit might improve matters?

Dirac Live, possibly. Not sure if it will integrate with Audirvana or if it will need a different software player. Might be worth browsing computeraudiophile forum for further info on Dirac or other alternatives.

Thanks Allan. Tried a few things now including demo of Dirac, killed the sound quality for me. The best so far is jriver dsp eq, targeting the problem frequency but that too kills it for me. The best solution is going to be large amounts of acoustic treatment, downgrade speakers (step down from scm40a to scm19a), or live with it.

Hi, Halloween Man. I wonder how long you've had your your SCM40a's? For the first 6 months, my passive SCM40's, suffered with overpowering bass, in my fairly small for larger ATC's room. By this time, I was already experimenting with DIY bass traps, and using a low shelf filter in jriver. I didn't notice any change in musicality with the filter switched in, but had to change the depth of bass cut for some recordings, which I found very inconvenient. I was beginning to wonder if I'd bought the wrong speakers, when the problem started to resolve by itself after about 8 months of running in. At this point I have to mention that I also started with a new NAP250.2, on the same date I installed the SCM40's..

I am very pleased with the sound now, and 2 years on, I'm really glad I didn't change the speakers.

Klyde posted:

Hi, Halloween Man. I wonder how long you've had your your SCM40a's? For the first 6 months, my passive SCM40's, suffered with overpowering bass, in my fairly small for larger ATC's room. By this time, I was already experimenting with DIY bass traps, and using a low shelf filter in jriver. I didn't notice any change in musicality with the filter switched in, but had to change the depth of bass cut for some recordings, which I found very inconvenient. I was beginning to wonder if I'd bought the wrong speakers, when the problem started to resolve by itself after about 8 months of running in. At this point I have to mention that I also started with a new NAP250.2, on the same date I installed the SCM40's..

I am very pleased with the sound now, and 2 years on, I'm really glad I didn't change the speakers.

I suspect you've just become accustomed to the bass, perhaps having had a bass-light system before. The ATCs aren't exactly heavy in the bass.

Halloween Man posted:

Thanks Allan. Tried a few things now including demo of Dirac, killed the sound quality for me. The best so far is jriver dsp eq, targeting the problem frequency but that too kills it for me. The best solution is going to be large amounts of acoustic treatment, downgrade speakers (step down from scm40a to scm19a), or live with it.

I also tried Dirac and found it killed the music - too much correction makes it all artificial. Although I haven't tried for myself, as AP identified you can use AUdio Units to set up a parametric filter with Audirvana - the important thing must be to get it right. THere is free Mac app called REW (room equalisation wizard IIRC), but you need a reasonable microphone to use it (one I have ised is the Behringer ECM8000, but there are others). Don't try to make the room flat, but simply reduce the worst of the resonance at the listening position.

Hi ib thanks for the info. I have now tried that and can see a massive bump at 45hz that moving the speakers does very little about. The peq of audirvana doesn't sound great so I'm about to invest in lots of bass traps, tuned to 30-60hz.

i can get rid of the bump by moving sofa to near middle of room but that is just not practical.

Hi klyde. I wonder if the tweeter and mid took a bit longer to run in and therefore later made it sound more balanced after a while. No doubt 250 drives the speakers well. I have the active versions so no amp. Thanks.

ib on paper scm40 appear bass light but in reality they are very much full range speakers with large amounts of bass energy that my 4m x 4m room is struggling with.

Halloween Man posted:

i can get rid of the bump by moving sofa to near middle of room but that is just not practical.

Middle of the room is usually the other extreme,mwith the bass near cancelled (before room treatment), so likely to be bass light. Usually about a third or two thirds of the room is better (IIRC there's a theoretical ideal of 0.38 of the dimension). But practicality has to rule in a family home - unless ther's the option of moving seat forward when serious listening, otherwise leaving it close to wall.

Halloween Man posted:

ib on paper scm40 appear bass light but in reality they are very much full range speakers with large amounts of bass energy that my 4m x 4m room is struggling with.

My observation was picking up on your assessment that seemed to say you originally found the SCM40s bass heavy, but after 8 months they started to improve and after 2 years you were happy with them - which wouldn't be bass decreasing, rather you coming to like it compared to what may have been a bass-light system before you changed to the SCM40s.

But that's nothing to do with the bass reflections, which can certainly cause certain parts of the room to have excessive bass at some frequencies - and other parts of the room no bass. I've seen your other thread, which has beveloped into an interesting and useful one for anyone suffering anything similar.

hi ib, i think this was clyde.

i only had my scm40a for a few months. it took a few weeks for the speakers to settle down and to be honest since day one the bass response has been too strong at the very bottom end for my room. ironic as before i purchaed i thought they would be bass light after looking at the specs and comparing to my existing pmc 20.23 specs.

im only now beginning to understand the room problem and tackle it as discussed in another thread. it will be interesting to see what effect acoustic treatment has.

Room treatment vs. an extended home demo of SCM19a.

It sounds rather as though you didn't do an extended home demo if there were detectable bass issues from day one, and that the speakers are simply too big and too bassy for your room. Bass traps sound rather like treating the symptoms rather than the disease. Should you be taking a different approach?

Halloween Man posted:

hi ib, i think this was clyde.

 

Sorry, my mix-up! 

Hungryhalibut posted:

It sounds rather as though you didn't do an extended home demo if there were detectable bass issues from day one, and that the speakers are simply too big and too bassy for your room. Bass traps sound rather like treating the symptoms rather than the disease. Should you be taking a different approach?

The room unevenness will of course still be there, as in the 45Hz frequency will be boosted relative to frequencies above and below in the same places in the room, just less prominent so not so obvious, or to put it another way round, if the 45Hz level is correct relative to the bulk of the spectrum, frequencies immediately above and below will be quieter relative to the whole spectrum. Reduction of the standing waves is the only way to even out the response (other than modifying the signal to compensate).

However the reality is that real rooms have peaks and troughs - and other adverse effects such as early reflections - and the majority of people probably only listen in untreated rooms unless a significant problem exists, so are quite unaccustomed to the sound of a treated room which can then sound 'wrong' (different for surround sound, where the multiple speakers provide the ambiance). There is always the debate as to whether or how much room treatment is desirable, both in terms of 'killing' the sound if too much, and/or available space especially in smaller rooms, and/or aesthetics, particularly in rooms that aren't dedicated to music listening. The biggest problems tend to arise in a square room, or nearly so, (or even more so a cubic room) making the peaks more prominent as they are additive, when treatment might be the only way to get anywhere close to a tolerably even response.

Trying speakers with less bass output in the room would be the only way to determine if that is the appropriate solution in this particular case - however as far as I am aware the ATCs below the SCM40 don't have that wonderful midrange unit, which could be hard to live without.

Hungryhalibut posted:

It sounds rather as though you didn't do an extended home demo if there were detectable bass issues from day one, and that the speakers are simply too big and too bassy for your room. Bass traps sound rather like treating the symptoms rather than the disease. Should you be taking a different approach?

I disagree, acoustic room treatment specifically corrects (albeit only partially) for the fact that we listen to our systems in various differently sized, differently shaped, internally reflective and sub-critically damped resonant boxes.  It isn't treating the symptom, it's directly addressing the cause of the problem.

Digital room 'correction' on the other hand is treating the symptom rather than the cause.

Specifying speakers that have rolled off bass is just avoiding the problem by throwing away all the frequencies in the signal that are approximately in the same area that interacts with the room; unfortunately along with the troublesome frequencies, this also throws away a lot of other desirable bass information present in the signal.

Hungryhalibut posted:

It sounds rather as though you didn't do an extended home demo if there were detectable bass issues from day one, and that the speakers are simply too big and too bassy for your room. Bass traps sound rather like treating the symptoms rather than the disease. Should you be taking a different approach?

I noticed the bass from day one but decided to live with it. The problem really is the room, not the speakers. The problem will exist no matter what speakers I get. I dont want to limit myself to a pair of tweeters! I've decided to attempt to treat the room which is the root of the problem. its not a little spike, its huge and very distracting, about 12db at 45Hz.

i did check with atc before purchasing and they assured me the speakers were suitable for the room size.

as IB suggests the mid range on the scm40a is worth the hassle. all else fails i will step down to scm19a

I've had 2 week home demo of a passive and run-in SCM40 (driven by a run-in 200, 282, V1, and MM with Audirvana) and fully appreciate the captivating delivery of the mid driver and thought very very hard about keeping them. However, the force and amount of air shifted by the bass driver in the SCM40 did excite the listening room and other parts of the home.

I have since gone with PMC Fact3s which, to me, have a greater sense of coherence over the SCM40 and, according to specs., cover a broader range of frequency. I listen from about 2-3m from the speakers.

Not sure whether the 40a or 19a are more coherent because of using active crossovers.

I am not advocating buying without extended listening (especially as drivers and amp run-in may have a part to play in these actives), but given that there is some focus on specs and application of physics in this thread, my approach would to trial the SCM19a - as their frequency range is only slightly different and bass roll off will be similar as they are both closed box designs. Also, the combined mid-bass driver of the 19 has a built in dome of the same size and with a better specified bass driver.

By doing this, you give yourself the option to potentially reduce the amount of room correction needed in whatever form (which acknowledged by posts above that may only partially reduce the issue - are all recordings and mastering perfect? Are all electronics perfect?).

Good luck

Jude

Thanks Jude, will bear that in mind. The last option really is going to be stepping down speakers. I'll try acoustic treatment first and see how it goes. I know what you mean about the energy from the bass driver.

Fact 3 do look to be excellent speakers. Before the ATCs I have pmc 20.23 and thought they were superb. Just a couple of things in the end made me change, house move, and tweeter was very strong and made many poor recordings sound very unforgiving.