Axiom Home Page Forums General Discussion Technical Questions Understanding Graphs, roll off and M100 querys

Maybe should split these upinto different posts but i'll see how this goes...

First thing, looking into the m100 specs, the standard tower specs vs the wireless version with built in amps, shows not identical specs. Im wondering why this is?

IE: the weights are different...ok fine, one has amps on board the other doesnt. No problem, makes sense.

But the sensitivity are one db difference. Not a big deal, could be affected by cabinet internal volume perhaps with amps versus no maps inside.

But the crossovers show a 40 hz difference in the mid to low range exchange, and the mid to high frequencies show a 0.3hz differnece at hat handoff. Just a typo in the spec sheet? Or is there actually a slightly tweeked crossover between the 2? Or is it the wireless version v4 specs and the m100 tower spec sheet is an older version and juist not updated? I'm kinda doubting the crossovers are sold different as I know Axiom is stalwart in their quality control within there " reference " modeling they use to keep continuity within the brand, IE not using " matched pairs" to ship out or worriying about sequential serial numbers etc.

I'll ask my roll off question in a bit as I continue my m100 research.

Very good. Look at you go! It's quite possible the cross-overs are different to account for the different volume due to the amp. The frequency response curve can't be correct either.

Ok good. I’m not crazy then. But a 40hz crossover step seems like a lot.

The only reason I noticed is I was exploring maybe the wireless m100. No wires seems nice but I’m not convinced. Plus those are way less likely to come up on b stock etc.

As for the the graphs the bass roll off doesn’t look like what I’ve heard described by owners of m100. It seems to start a soft roll off quite high versus the deep bass that this tower is touted as having. But I will admit I don’t exactly correlate well with understanding roll off and db loss versus octave in the real world. Looks like 30 hz is achieved but but 10 db or so from roll off starting point.

As for the cross-overs, it's quite possible they reflect a new production version of the family of curves. For all we know, that new version may be in the wired M100s too and the specs are wrong for that model.

The bass blooms in room so bass down to 30Hz or lower is possible.

Yeah. I bet that’s the case. The wired version probably just needs an updated spec page. My hope is that the m100 can produce the bass and emotion I want in room with out subs.

My room is very large but where does one stop measuring cubic volume? If I include EVERYTHING that is attached in terms of open space than it’s very big. But if I include just the “ immediate “volume it’s just plain big but not insane.

Everything that is coupled to the airspace.

Define coupled…?

Does a closed door “ decouple “ ( to use the term loosely )

What about the standard stairwell to the upstairs? It’s a contained stairway but rises 18-19 feet to upper ceiling.

Thankyou!

Define "door".

Standard interior door that connects main living space to a 600-700 cubed mud room.

So basically a hole.

Ha ha ha ha!!! Nice. Yup. The next door beyond that is metal sealed door into garage.

Hmmmm. So maybe my initial volume calculation was correct ? I’ll remeasure. But I guess the bottom line is I can classify it as large so it doesn’t really matter in the end. I don’t think I’m in any danger of over pressurizing the space.

Ideally a pair of m100 with an Ada 1500 is all I need to get what I’m chasing.

Closed Door = Not coupled.

Heavier door the better. Ideally same STC as wall assembly in room.

Worse issue than additional cubic volume to load is random RT60 behaviour or echo from adjoining space reflections heading back into the room.

Does the time allowable for rt60 increase as the room gets larger? There must be a point where you can’t effectively reduce rt60 decay to the same levels in 2 very different room sizes, say a 2500 cubed room versus a 8-9000 cubed room.

Or is the desirable rt60 standard across the board regardless of room size? Say less than 0.5 ?

( Please correct me if anything I’m saying here is incorrect! I’ve been reading about this stuff but my understanding is superficial at best….).

I guess the real question is what is the standard and are they realistic?

Yes, as the room gets larger rt60 target times increase.

For living spaces you are targeting 0.45s on the long end to 0.2s to shortest time.

In a large room the longer time. In a bedroom 0.2s.

In a theater or 2ch room around 0.3s.

Measure by popping a balloon and using rt60 tool in Audio Tools or REW.

Carpet, window coverings and plush furniture advantages for sure.

To make it easier on you buy this book:

https://www.amazon.ca/Handbook-Sound-Studio-Construction-Recording/dp/007177274X

Includes everything you need and more.

Thanks Trevor. Super helpful. I’m starting my planning for our basement listening / media room. Hoping to start the build in the late spring after my work season ends. I’ll buy the book for sure. I’ll be doing the planning and design in between work projects over the winter. Looking forward to it.

Our living room is also still an ongoing work in progress. I think the media room might happen faster from a ground up build!! ( that’s the difference between me deciding on the media room and my wife deciding on the finishing of the living room!).

The rt60 will be a way bigger factor in the living room than the basement me thinks.

Maybe the quickest project will be our bedroom. Should be straight forward. House is finally painted interior so we can start putting our belongings into everywhere and making things normal. It’s been a moderate road of deficiency’s to get things looking good in the whole house.

I’m inspired by 2x6 with a dedicated system in every room in his house seems like!!

Trevor recommend both the book and AudioTools to me a while back. I can 2nd both.
Of the books I've looked at this was the most concise and most practical one by far. Wish I had it when I was first planning my HT.

AudioTools also seems to be a really good app. I have not used all the tools yet but so far I'm happy. AudioTools come with a minimum set of plug-ins. All the others, some of which you'll want, are ala carte.

Instead, I bought AudioToolsMax which is AudioTools with everything enabled (including anything which comes out in the future). It was a bit pricey even on sale (think the sale was something like 30% off at the time). I justified it because it had tools not only for room measurements but a few others I knew I'd need sometime in the future (like testing THD and noise).

One Note: Audio out on the newer iPads requires some sort of interface now that they no longer have a phone jack out. I have an older iPad I'm keeping around which is good enough for room tuning.

Another comment on the specs of the m100....I was comparing the m100 crossover points to the LFR 1100 passive and LFR 1100 Active ( being their big brother and all) and the specs show them crossed at 200hz and 2k...so that must be the current state of affairs for the m100 v4, standard and wireless. Unless theres a good reason to cross the wireles version differently.

Specs are kind of a starting point ... they never quite tell the whole story and are often misleading. Even so they are important ... so ... that said ...

I'm never sure about the specs and graphs here ... I think Axiom often changes stuff and then drags their feet on updating the specs on it. I understand it from a engineers point of view ... I did the fun/important stuff ... I'll take care of the getting/updating the graph and number stuff later ... never quite getting to it ...

From a marketing/sales perspective the specs and graphs are what people obsess over ... I mean to the point of insanity ... on paper a db of SPL or S/N can be the difference between buying your product or a competitors ... even though in most cases a db will not make an ounce of difference in performance.

But still, it's important that they be right even just to know which speakers in the Axiom line up you might be interested in.

One one hand, It's kind of what I like about this outfit ... more engineering minded then marketing minded. On the other it's sometimes a bit frustrating to be trip'ed up by an out of date or misleading spec.

Hey thanks rrlev. I’m not obsessed about it so no worries there. I’ve been comparing more out of curiosity and learning. Trying to understand the graphs better by looking at the graphs and frequency response and impedance curves. I think what you say makes a lot of sense. I totally get it from operational point of view, who cares if everything on the website isn’t totally up to snuff, the engineer and internally they know everything is as it should be, good enough. They know they have great products.

However, its more about how it looks overall to the customer looking in. Details really count to some people and other industry’s wouldn’t tolerate it.

I agree, a db here or there don’t matter at all, +\- 3db right!?:)


And I totally agree, I like how down to earth the company seems and not entrenched in “ audio politics “.

I just spent a week of on off music/movie sessions retuning my theater with Dirac after upgrading to M5OW surrounds. Many filters were tested using their 17 point measure process on a PC.

In a fully treated room, 1db changes in the vocal range are very audible and can make or break the realism of playback. I found that tweaking things in room with Dirac was far more relevant than what speaker was deployed.

The most important spec. aspects are power handling, distortion, dispersion and bandwidth. The rest can be tweaked these days using dsp with results that fool the senses in room.

Anechoic graphs are a great yardstick to compare products. These days you can make pretty well any speaker sound as you like with DSP barring pushing them into distortion while tweaking. -Not an issue for Axiom products.

I'm very interested in trying Dirac and ARC. I've heard great things about both.
I've only used Audyssey and now just skip it and do everything manually.

I may not be giving Audyssey a fair shake, but I find I need to adjust things after I run it. I'm also optimizing for MLP and not all the seats, so before dissing I should test more: listening in the other seats and compare Audyssey to my manual setup. Unfortunately, this takes time and motivation to actually do it.

If and when prepros with over 16 channel come down in price I'd like to upgrade to Dirac (or perhaps ARC).

Your comments are interesting to note as a 1db bump in loudness is supposed to be barely audible (at the threshold most people can detect). I guess it makes sense that subtle changes in frequency response can reflect in shifts in the tonal character of sound as the make up of tone is a ratio of harmonics. So this ratio must be easier to perceive than changes to the overall loudness ... I probably read about that somewhere but didn't absorb it ... might be interesting to lookup/check out.

We were messing with 960hz. Wide band of Q maybe like whole octave wide.

Increasing from +1db to 1.6db was readily detectable.

You nailed it in another post. When you change anything its at the expense or detriment of something else when you are really dialed in. When you hit spl listening levels what ranges contribute to the balance and weighting or priority is a tough juggle when making adjustments.

Yesterday I cut up Axiom shipping foam to make port plugs for my super towers. Work great actually. I was able to revisit Dirac and put a couple db back into the upper bass range around 150hz. Really filled out plucks of upright bass and sure sharpened things up. But, only because I know the system and it is a pretty controlled space. In a live room may not have been as important as other factors.

I also got Audiotools though not with all the added plug-ins.
I really don't like using the tablet/phone for taking sound measurements but short of setting up something more elaborate, it's what i used.
Still trying to wrap my head around how much Audyssey changes the room curves. Things are subtle and in some cases seemingly not at all when looking at before and after curves.

Wow. Great discussion above and responses. Right on. Well here is another thing I noticed. The spec on the m60 is ststed as handing of the mid range to the low at 500hz. That seems reallly high to be handing down the midrange to the woofer. I would think the spec should be similar to the m80 and m100 and handing off at 160hz or 200hz. Thoughts?

Also, the center channels are stated as handing off at 500hz, is this correct? I'm not knowledgable at all with anything center channel or 5.1 etc surround stuff. It's glaring blank in my knowledge base. My 2 channel knowledge is improving though, I think some of what i've learned is actually true as well. ( Ha ha.)