Anyone prefer 100hz crossovers? - Page 4

Right.

It depends on output level and program material.

At the listening levels I prefer (about 85dBC average for jazz) on acoustic recordings with good dynamic range the numbers might be 140-180Hz and 100-120Hz respectively using even order cross-overs at those points and about 250 and 170 run full-range.
Edited by Drew Eckhardt - 11/29/12 at 3:24pm

Anechoic, yes. But because below cutoff they're monopoles (just like any closed box) they have enough output to excite modes below 45Hz, though. Dr. Geddes has mentioned EQ'ing them below cutoff in the past.

Also, you should read some of the more recent exchanges on diyaudio.com between Dr. Geddes and Dr. Krevosky ("john k") about bass in rooms.

OK, whatever (a smarter definition would be "frequency range where room modes are so sparse that placement no longer works to materially smooth out response"). I'm stillnot sure how that's relevant here, unless one defines "subwoofer" as "device that plays just below 20Hz."

What are the theoretical defects of his approach, and why would they matter for facsimiles of synthesized impressions of fake events, but not for, say, a the multichannel SACD of Dark Side of the Moon, or the multichannel DVD-A of R.E.M.'s Green, or the Blu-Ray of Radiohead's "The King of Limbs: Live from the Basement" show?

Why not? If the midrange is big enough, it won't move appreciably. I ran 12" concentric drivers full-range for years. They were in closed boxes, and between the air-spring and their very high impedance at ULF their cone motion was well controlled even when I watched the Black Hawk Down Blu-Ray on that system. (I don't find myself watching a movie more than once, which is why I no longer buy them. And repeatedly re-watching scenes of a bunch of soldiers running out to board helicopters...not my thing.)

Hmm, fairly small closed boxes with 5.5" moderate-throw woofers (IIRC, OEM variants of the Peerless CSX145), IMO you'll probably want a highpass on them, because they're a little light on volume displacement. Two of them barely out displace an equivalent single 7" woofer (Two 5.5" Peerless CSX midwoofers displace about [edit] 165cc. [/edi] The 7" woofer in that line displaces about 20cc less. A good 8" midbass will displace closer over 300cc.) [/edit]

[previous numbers listed used the wrong value for xmax; I accidentally plugged in voicecoil diameter for voicecoil height in my erroneous earlier "calculations." Guesstimations is perhaps a better word.]

But never know until you try it. If your room is fairly small and the speakers are close to the front wall, it may work just fine.

Also, four 12's sounds like a lot of sub for those mains to me, but maybe it's not if movies are the system's primary source material. You're also lucky to have freedom to place the subs based on measurements. I'm generally more concerned about how my home looks, so subs end up going where they can be easily concealed.

Lastly, if you want two of NHT's A1 monoblocs for those Evo subs...I happen to know of two sitting idle in their boxes, thanks to this glorious beast..
Edited by DS-21 - 11/29/12 at 10:16pm

Each of my main speakers has one 8.5" mid-bass and a pair of 10" sub-woofers in the same cabinet with a 120Hz 4th order cross-over.

They're dipoles so the physics are a little different. The mid-bass limits match the same driver in a box at 240Hz but only do as well as a 7" driver at the 120Hz cross-over. The sub-woofers match one box mounted 10" sub-woofer per side at 80Hz (two total) and do half as well at 40Hz where all four only collectively match one 10" sub and are down to half that by 20Hz.

They run full-range for music (even "bass heavy" music like rap has little energy in the last octave) but I cross to a 15" sub-woofer for home theater.

The bedroom system is smaller with one 5.25" mid-bass driver per side crossed fourth order at 100Hz to stereo 10" sub-woofers. The midrange drivers get strained at reasonable critical listening levels (but are much more usable than when run full-range) although when we play music there it's probably close to bedtime when quiet is nice so that's not too big a deal. I've been meaning to upgrade to 6" midrange drivers although it's low on my priority list.

Definitely one of the topics that's not aired enough!

I'm running fronts that are made for being crossed at 80 Hz (but they do quite repectable full range) - they're 2½ way speakers with two 8.8" boomers. (If max 125dB@100Hz isn't enough, or you sit very far from them, the bigger brother uses four instead )

That is a great track to stress test a system.
The MasVis looks like a neat piece of software. I will give it a try.

It's not such a bad piece of music either if you've got a wide taste in music.

Do that, it's good if it spreads. The reason behind it was as another means to help stop the compression madness on music nowadays - a simple way for everyone to analyse music. It's a teacher at the Royal Tech in Stockholm who made it. Sound like you aleady found it, if not I'll go find a link for you.

yes, I like the whole album actually. cannot say the same about "Into the Great Wide Yonder"

The YPAO room eq. in my Yamaha RX-A1000 consistently selects a 200Hz crossover for the subs, which seems a little high. I found (both measurements and careful listening) that 110-120 seems to be the best compromise for my system ATM.

Geddes is still weak on details on what he does in his own room. He does discuss what you should do (AKA what he is selling) and is very vague on how to get from here to there. Try to get the ballpark high and low frequency limits of the band pass subwoofers that he uses in a room.

I do enjoy reading those Geddes postings.





I think that I have spent too much time on the bass in movies with charts thread. The majority opinion on that thread define ULF as Infra or sub 20 Hz content.

Here are some more basic definitions of bass that I like to use. For example, my JPC MBM is located near the seating area and covers (AKA overlaps) mid and upper bass (about 80 to 160 Hz).









Do you really know what Geddes is doing in his own room? How many speakers are set to large in his AVR, and how many are set to small? Where are those main speakers located in his room? What specific bass does Geddes route to his subwoofer(s), and how does he mix those signals? Does the bass plus mode work the same way for every AVR? For that matter does anyone really know how to use the bass plus mode?

I have looked at what Marcus posted for his Geddes evaluation, but he does not use the Geddes method these days. For that matter, I am not quite sure what you do either.






Do you still run 12" concentrics these days? Most people use a two way with maybe a 6 1/2" driver plus a tweeter. I would not run those as large.

Four 12" subwoofer drivers are required per the NHT speaker designer. The reason for that is the NHT crossover's HP filter is being lowered from the factory settings. This modification requires twice as many drivers and twice as much power to perform well to below 20 Hz.

I bought 3 extra of the NHT A1 amplifiers for cheap when NHT discontinued them. In my new room I may use a pair of the NHT 2.9's mixed with the Evolution speakers (M5 and L5), so the A1 will power those NHT 2.9 speakers.

Also note that I do not use the all small bass management settings in my AVR. Displacement calculations for a single driver may be deceptive because you do no know how I route the bass in my system.

Well I have spent the last few days with higher crossover points. Started off with 90hz as it gave a very flat response. Things did sound good as in clarity from the speakers and the flat bass up to at least 100hz before I started getting peaks and nulls in the FR. I had it like this for a couple of days thinking this wasn't too bad.

But I did get the sense that I was listening to a set of speakers and subs. I have a lot of live music recordings and somehow they didn't sound as real. To me it sounded more like I was listening to some speakers and subs rather than having the band in the room with you.

I dropped to a 80hz crossover at the expense of a slight dip in the FR and it helped a tiny bit to blend the bass between the subs and speakers. I still had the sense of I was listening to some speakers with subs though.

So last night I went back to a 60hz crossover at the expense of a bit more of a dip in the FR... but now the subs and speakers blend seamlessly in sharing bass duties as there is no sense that you are listening to the individual components of the system. It just sounds more enjoyable to me this way.

.
Edited by kiwi2 - 12/2/12 at 1:49pm

 

I've sort of come to the same conclusion.  Higher crossover gives flatter response but lower crossover sounds wider, more open and enveloping.  So they both sound good but in their own way. 

What crossover slopes did you use?

I am just using a Yamaha AVR, so whatever slopes it uses.

This is what it looks like though when I measured the subs and speakers by themselves with the 80hz crossover.

The peak at ~140Hz from the subwoofer looks like it could be a problem, if it's not an artifact in this particular measurement.

Looks like a 1st order HP and and 3rd order LP if I'm not fumbling the graph. I prefer a sharper cutoff than that, the filter I'm using has a 5th order LP (-30dB/octave)

So, I'm not surprised about your findings, for those slopes you've probably found the ideal solution.
Edited by Nightlord - 12/3/12 at 2:07am

At the end of the day, this is all a pointless battle of preferences. All that really matters is what sounds good to you in your home to your ears. Experiment and test and retest. My mains go down to 29 Hz so I have my avr set to small for all my speakers but crossover set to 40Hz. My 15 inch DIY sub is powered by a dedicated amplifier and is currently tuned to 18 Hz so for me it sounds great. What is important is that it sounds good to me. I find that I can go loud and clean with my setup and that is all that matters to me.

There are more angles to attack the problem from than that. If you want to maximize the use of your sub, then it is a corner placement we're talking about and it will receive good wall/floor support for all frequencies that a 1/8th wavelength is longer than the distance from the woofer to the boundary, which is about three inches shy of two feet at 80Hz, which shouldn't be a problem positioning a 15" within, if that was kept in mind at box design time.
To flatten out the room resonances, it is a good idea to excite the room from more than one location, both theory and practice points at "at least 4". Then you also benefit from having the distortion lowered and you gain some extra capability that you can use to boost the signal at ULF for great frequency extension (which also makes a case for multiple sealed boxes). That's a recipe based on physics and I know quite a few people that's happily gone down that route. But as discussed above, it might require a bit better crossovers than the standard AVRs to pull off a good transition. Not having to pump bass will only benefit the fronts capability (unless it already had a similar crossover point from it's bass driver).

Now, I do understand that a lot of people don't want to select gear by technical/physical aspects - for me it's been one hell of a shortcut compared to auditioning loads and loads of gear to slowly iterate towards the same goal.

I'm using 4x10" bass reflex subs for the tv room, 8x12" (NHT 1259) sealed subs for the livingroom stereo and 6x even more capable 12" subs for the theater. All crossed at 80Hz, only the small tv room system through an AVR and the latter two systems use infrasonic boost plugin-boards in the crossovers. My stereo mains are only -1dB down at 24Hz, so they're quite cabable when I flip to running them fullrange, but I do not have any drawbacks at all running them just from 80Hz and up. Quite easy to compare the difference with just a single switch to throw to compare - with some long cables to/from the crossover, you can have it with you in the listening position while setting levels, tuning Q, tuning infrasonic boost etc.

I think a 90hz crossover sounds best with my Klipsch Reference speakers.

A bit of an update that is kind of relevant to this thread...

Yesterday I experimented with different sub locations in my room and ended up with a setup that gave a reasonable measured FR with a 40hz crossover. My front speakers are rated down to 35hz so I thought I would run with the 40hz crossover to see how it sounded.

It sounds good! And I mean for the reasons I talked about previously in this thread. Soundstage is more dynamic with a fuller and more natural sound coming from the speakers.

It really leads me to believe that blanket recommendations for a 80hz crossover is not necessarily the best way to go if your speakers are capable of playing lower than that.

Good for you!

Generally the issues that come up from doing this is (at least) twofold:
1) Your main speakers will not be relieved of the bass duty, so you probably lose out on being able to play as loud (unless that limitation sits in tweeter anyway)
2) You will be radiating longer wavelengths from the main speaker position and these will be more likely to give interference issues from room boundaries than they would from a corner placed subwoofer where you could keep the reflexes say within a quarter wavelenths phaseshift from the direct signal.

If 1) is of no concern and 2) does not create acoustical issues in the room in question, then no need to worry about 80Hz.

People with very bass-intense music tastes might need to go the other way, say up to 125Hz to take more power load off the main speakers.

Here is an optimistic analysis of the bass dynamic range of 2x 5 1/4 speakers such as are found in the CSI30:

Freq,Hz Max SPL, DB

10 69
20 81
30 88
40 93
50 97
60 100
70 103
80 105
90 107
100 109
110 111
120 112
130 114
140 115
150 116
160 117
170 118
180 119
190 120
200 121

Their efficiency is a little above average.

If Polk slacked off a little on driver linear travel, or you push them hard, then you could be in trouble.

In order to overdrive them you have to be pushing them - into the 90-100 dB range which is really not that much.

As high end speakers I would expect them to be clean at outputs up to 110 dB, and that kind of duty suggests a 100-110 Hz crossover.

BTW this is an old thread! I went back and read some of the earlier posts. Many of the issues that came up here led me to develop my model (derivative of Linkwitz' work) of speaker maximum clean dynamic range.
Edited by arnyk - 3/8/13 at 4:35am

I agree with what you are saying and indeed I do notice the clarity and crispness with the higher crossovers at higher volumes. But then I find it sounds a bit too sterile and uninteresting at more typical moderate volume. It's like the body is missing from the speakers.

If I was going to use a 80 or 100hz crossover, then I may as well just brought myself small 4" satellite speakers.

My cinema fronts are designed for 80Hz crossover and they feature two 8.8" woofer/boomers. Their bigger brother (which I cannot afford and I also would be sitting too close to) uses four. 4" won't give you the output you need.

Here's a nice pic of someones specimens of the bigger brother:

This topic is something I've recently revisited: I used to have a mix of PMC front speakers (transmission line bass reflex loading) and much smaller M&K K4 tripole surrounds (and K5 monopole back surrounds). I have an older,but superb, Arcam AV9 processor so I use my Oppo 93 for analogue decoding of HD soundtracks. It only has a single global crossover setting so it's always been a compromise. Recently I managed to find a used pair of PMC Wafer 1 wall mount speakers to replace the little K4s with and the Wafers go much deeper than the K4s (as well as being a much better tonal match for my front PMC speakers.

Anyway after all this changing round (and I moved the sub a bit and rerun the Antimode 8033 EQ) I tested various crossovers. Like Kiwi2 says I get better clarity and crispness using a higher crossover (100Hz in my case despite all the PMCs being rated to 40Hz) especially when listening at near reference level as I tend to when using my projector. However, I've also found that at lower listening levels when watching TV it does sound a bit too sterile, so I'm lucky that my Arcam AV9 has 5 presets which allow totally different crossovers, speaker levels and many other settings: I use an 80Hz crossover for regular TV listening (mostly Dolby Pro Logic IIx or DD IIx for those channels that broadcast in 5.1). For projector use I use a different preset in the AV9 with the 100Hz crossover. This is despite the low end response of my speakers (which are biamped with separate power amps too).

I'm sure some of my issue is that my centre speaker is too low which causes resonance with the oak floor, but the TV means it can't be raised. However, when using my projector the screen is a little higher, so I'm considering making a stand that can be raised for (more critical) projector viewing since it doesn't matter if the centre is in front of the TV screen then. I may be able to lower the (global) crossover a touch if I can fix this resonance issue with the centre, but given how clean it sounds around reference, I may just leave it set to 100Hz crossover anyway (plus I'm getting a bigger, but sealed, sub later this year as that is now my limiting factor at higher levels since it's only a 300 watt 12" ported sub).

After all these years of having AV gear (16 years and counting) I'm still tweaking, calibrating (and still learning).
Edited by Kelvin1965S - 3/11/13 at 3:02pm

Agree with the volume/crossover discussion as well!

Doing so would prove nothing is this case. People buys subwoofers in living room/HT set ups, because their speakers generally speaking, are not capable of outputting a full range of sound.
It is not reasonable to assume that someone will have the same settings on their amp or receiver WITH a sub as they would WITHOUT one. When you add a sub to an existing multi channel system, you should then adjust your sound settings accordingly to BLEND then subwoofer range with your speakers range. Playing one without the other at that point is meaningless.

Tell that to Nightlord above!


I said to try that in the context of when we were talking about changing what was stereo to a mono sub output as in what happens with typical bass management on a AVR.

i.e. How could you have a dynamic soundstage if 120hz and below is turned to mono. Listening to your speakers by themselves with a certain crossover but without the subs powered up can be quite revealing.