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In Reply to: RE: 150 hz. is awfully high... posted by morricab on December 02, 2014 at 04:33:45
Hi and taken from the same magazine the curves for the Zingali Home Monitor 2.10
Much better
Kind regards,
bg
Follow Ups:
Keep in mind that these are frequency (anechoic) response curves created by measuring with the speakers away from all boundaries or in an anechoic chamber.
In reality speakers are used in rooms and thus what you actually hear are the frequency response +/- boundary reflections i.e. the in-room power response.
Power response curves are usually dramatically different than frequency response curves and are closer to what we actually hear when listening to speakers in a room.
A typical room is going to boost the low bass of the speaker (shelving bass boost) so the frequency response bass roll-off points can be mis-leading.
Hi and thank for the advice
but i seriously doubt that a minimonitor can give a realistic piano even in a normal room
The problem i think is that many like myself are used to small speakers
and we do not know what we are missing ... the real thing
Of course available space is often a constraint
Kind regards,
bg
A mini-monitor can actually give a realistic piano sound in a normal sized room but they will need (proper) boundary re-inforcement to do so.
One of my favorite record shops, Academy Music in Manhattan, has Harbeth mini-monitors sitting on a high book-shelf above the classical section. The speakers are sitting in close promimity to the ceiling. They sound superb with piano.
The (bass) re-inforcement of the ceiling boundary and the fact that the speakers are not placed equidistant from any two room boundaries helps the speakers in-room response to remain ideally flat and accurate. I hear no huge dips or peaks. Placed this way, the speakers sound faithful to the (piano) recording.
However, if you placed these same speakers on 3 foot high stands, 3 feet from the backwall and six feet from the ceiling you will get a 9 dB null at 113 Hz everywhere in the room and the piano will sound small and miniaturized.
Well this is interesting but difficult to get
and then there is the soundstage ... with speaker under the ceiling the perspective would be a little strange
A good size speaker could be easier to place in the room i guess
A speaker like the old Kef 105 is big but not impossible
or something similar size and concept
i like the head above the bass box concept a lot like in many famous speakers
Thanks for the advice
Kind regards,
bg
Stereo soundstaging is an illusion. It does not occur with live music and is not necessary to enjoy music. Moreover, the illusion does not occur in the far field or outside a single sweet spot in the room. Yet a piano can still sound like a piano in the far field. This is what other posters were describing with their next room analogy.
Your example of the large KEF speaker is an interesting one but that speaker must obey the same laws of physics that govern the behavior of the mini-monitor and the same placement rules apply.
Hi and i have another approach
Soundstage in a recording can even be created at the mixing desk i guess
But my point is another one
If there is a 3D effect, real or fake, i want to hear it
Because this means that the playback system is resolving also very fine details
It is a very good monitoring system
Of course if the piano in the recording is diffused i will hear it like it is in the recording
I have some test disks ... i know that they have depth and also layers in the depth
Not all the systems are able to give back this depth and layers
This has to do with resolving power
It is like a out of focus lens, not clean ...
I like terms like razor sharp, crystal clear ... and so on.
Then if the 3D effect is real or not is not important to me.
But i want to hear it all. And well.
Kind regards,
bg
Here are Stereophile's measurements for the KEF LS50. You'll notice that it has significant bass extension to well below 80 hz. Representative of typical bass performance for the small, high-quality, two-way loudspeakers of today...
Also look at the Soundstage measurements. Soundstage utilizes the NRC anechoic chamber, so their measurements understate bass output because they can't account for room gain. On the other hand, Stereophile's quasi-anechoic measurements overstate bass output due to the near field measurement technique. Real world performance tends to fall in between the two.
One thing you get from the chamber measurements is distortion, and as you can see from the Soundstage measurements the distortion is quite high at and below 100Hz at 90dB/2m. That suggests to me that this speaker is not really suitable for use in large rooms.
- Most modern, high-quality, two-way mini monitors will produce fairly flat bass response down to at least 80 hz, the maximum crossover point recommended when using a subwoofer...- If crossing over from the mains to the subwoofer at a point higher than 80 hz, where bass starts to become unidirectional, it is better to use two subwoofers (or one per speaker and each sub in close proximity to the main speaker) in order to preserve stereo separation and imaging. Otherwise (for example), you'll be listening to a bass or baritone vocalist recording and all of a sudden, the vocal imaging will switch from the 3' high level of the mains speakers down to the level of the floor where the subwoofer is located, as the singer traverses the lower depths of his vocal range.
Edits: 12/02/14 12/02/14
Genungo, you're basically on the right track, but your specifics are wrong.
The scientific literature shows that at about 80 Hz, we are able to discern the source direction of a sound. Given this, an 80 Hz crossover to a single sub is inappropriate for a stereo high fidelity system. 50 Hz is about the max for the crossover point.
However, as has been noted here by Duke and a couple of others, an even better solution is to have multiple subs in multiple locations. As an added bonus, you could put two of them toward the left side and two toward the right side, thus maintaining stereo separation and reducing the room issues while still being able to cross over at higher than 80 Hz.
:)
I understand that a crossover setting below 80 hz is often helpful because the rolloff rates of both subwoofers and mains speakers must meet and combine, effectively, at 80 hz or below. So, if the mains speaker start rolling of at 80 hz, we might need to set the sub crossover as low as 40 or 50 hz.My mains standmount speakers start rolling off about 80hz, and I've always found that using the 40 hz crossover setting on my subwoofers makes for the best sub/mains bass integration. I like to use the lowest possible subwoofer crossover setting combined with the highest possible subwoofer volume setting so that I get maximum grunt from way down below with less risk of excessive sub/mains overlap.
Edits: 12/02/14
Just to add another factor to the bass response of the LS50. It will get poorer(roll off sooner) the higher the volume. The lowest bass is primarily from the port. And the Soundstage measurements show the impedance rise from the port is lower than from the driver. That indicates the response of the port weakens before the response of the woofer at high inputs so there is less port reinforcement at high levels.
The problem is the port has to be larger but in a small box this can't be done.
Yes, the LS50, and many other speakers today with little woofers can reach down to 70, 60, 50, 40 or lower Hertz regions.
They can even do it with very low distortion.
What they CAN'T do is accurately reproduce the recording at those frequencies at 100 dB as measured from the listening seat.
Yes this is the point
We have 3 parameters: SPL, distortion and Frequency.
To get realistic SPLs, with low distortion at low frequency a big woofer is needed
If a piano is not enough let's use the Bach's "Toccata e fuga" and we will feel the difference
Kind regards,
bg
It doesn't matter what the parameters are if you cross over to the subwoofers at 150 hz or higher. If you do such a thing without placing those subwoofers within inches of the main speaker drivers, you are asking for trouble - worse sound, rather than better.
If you use two subs in a stereo configuration, I think there is more flexibility than you think.
The two subs need to be located in the front half of the room and placed symmetrically with respect to the listening position and speakers. And the two subs must be reasonably far apart so that if you draw a line from the listening position to one speaker and another line from the listening position to the corresponding sub, the angle between the lines should be no more than 10 deg in the horizontal plane. Futher, if the distance from the listening position to the sub is significantly greater or less than the distance from the listening position to the speaker, then time alignment is also required. Based on my own experience, I think if you follow these guidelines you will have no problems with imaging in the bass range.
The picture illustrates the two subwoofer placement options which work best in my downstairs room (please note the picture is only notional, things are not to scale). At one point in my system's evolution, I was using a 100 Hz 2nd order LPF on the subs and no HPF on the small standmount speakers, based on the idea that a minimal/low order crossover would give the best transient response across the bass range. I used multiple bands of parametric EQ and shelf filters on the subs only, in order to flatten the combined response of speaker + sub in the overlap region of 70-120 Hz and then cut the subs off quickly at 120 Hz.
With the subs in position 1 (next to the speakers), they suffered from a deep quarter wave null in the mid-bass caused by the front wall reflection, same as the main speakers do. With the subs in position 2 (near the front wall) they do not suffer from a mid-bass null, but time alignment is necessary due to the extra distance to the listening position. With capability for time alignment, the second position was objectively and subjectively superior, by more than a little bit, and even imaging of low frequency notes seemed better than in position 1. Without time alignment, an interference null is introduced with the subs in position 2 and the transient response suffers a bit, so it becomes a toss-up which position is better.
My experiments did not involve crossover frequencies as high as 150 Hz, but the same principles should apply. There are manufacturers who have used this approach with even higher crossover frequencies.
But I also have to admit that I'm not using that configuration any longer, and although I'd like to try again it probably won't be soon. My present components (network audio player and integrated amp) offer other sonic advantages that are more important to me now than optimizing subwoofer integration.
It is obvious that you were trying to deal with some unusually difficult acoustical problems. You did some unusual things in an effort to overcome those problems. The solutions adopted by you in the above scenario must have seemed necessary in the face of extraordinarily difficult acoustical problems, but those solutions are far from recommendable IMO.Because of the virtually insurmountable acoustical problems that you faced in your "almost square" listening room, you were forced to use solutions that are not typically recommended. I admire you for your toughness and persistence, but let's not pretend that what you were doing was something that should be considered in more typical circumstances.
That said, I do know the feeling...
I once had an "almost square room" and no matter what I did while attempting to overcome that acoustical problem, I could never get the bass to sound right. The dimensions of the room made it impossible to get truly decent sound. Unlike you, I finally gave up on the struggle by foregoing the idea of using loudspeakers in such a horrible room. After trying out some of the same "solutions" as you did, I finally put the speaker system in storage and broke out the headphone system...
"Ahhhhh! Much better now!" Best decision I ever made.
Sometimes, it's just not worth the struggle...
Edits: 12/04/14 12/04/14
I wasn't trying to draw a picture of my room. Like I said in the previous post, it's just a notional illustration of the two different placements. The real room is more complicated, not strictly rectangular or symmetric. Anyway, the experiments I was doing reflect the fact that I'm an engineer and enjoy that stuff more than they reflect any extraordinary room specific issues.
My current setup in that room uses conventional subs with a more conventional 70 Hz LPF setting and no digital XO, but that's mainly because I really like the sound of my current Linn-> Ayre-> WB combo and it doesn't allow for anything fancier.
Also, the specific placement tradeoffs I was investigating are not unique to my room, they exist in every listening room. No matter what speakers you use or what room you use them in, there will be quarter wavelength nulls which depend on distances from the drivers to the front wall, side wall, floor, and ceiling. In a small-medium sized room, a very typical audiophile speaker setup has the speakers located 2-3 feet from the side walls and 3-4 feet from the front wall (or possibly vice-versa for long wall placement). With this sort of placement, there are always going to be nulls in the bass and lower midrange, and the null due to the front wall reflection is going to be somewhere right in the middle of the bass. If you place subs right next to the speakers, their response will also have the same null.
These nulls don't depend on the squareness of the room, only the proximity of the speakers to room boundaries. A square room presents a problem with overlapping room modes though.
The whole point I was making is that it's not necessary and usually not recommended to place subwoofers right next to the speakers, because the best location for optimizing the mid & high frequency response and soundstaging is rarely the best location for optimizing the bass. This is true even with a high crossover. And there have been several high quality commercial loudspeaker systems designed to have separate independent bass modules with a crossover of 100 Hz or even higher, including Lyngdorf, NHT, Audio Kinesis, and GedLee. It is a perfectly valid approach.
Back in the days when vinyl recordings were the name of the game for most people, bass was summed to mono at 100 hz. So, it used to be more of an OK thing to use a subwoofer crossover point of 100 hz, because doing so would not necessarily degrade stereo imaging and soundstaging.Now flash forward to the digital age where the cutoff point has been lowered to 80 hz, which corresponds to the point at which bass begins to become omni-directional...
If you listen to modern recordings with a crossover point from mains to a subwoofer higher than 80 hz, you risk shutting out some of the stereo information encoded in your recordings (unless you use two subwoofers that are, preferably, in very close proximity to the associated main speakers).
You say that the placement of subwoofers very close to the main speakers is usually "not recommended" but that would mean that the majority of classically designed tower speakers are extremely compromised designs (from the standpoint of acoustics), since most of them have immovable subwoofers in very close proximity to the other drivers. Attempting to keep each of two subwoofers in close proximity to the two main speakers in a stereo system is certainly recommended and is always worth trying before other placement options are investigated, when crossover points approach 80 hz or higher.
If using only one subwoofer crossed over at 80 hz or higher I would try to center it in between the two main speakers and keep it about the same distance away from the listening seat as the main speakers. And possibly, close to same height as the main speakers too...
Omni-directional sound has a unique sound signature. The ears can sense the shift from omni to uni within the context of a stereo soundstage. 100 hz should represent *the extreme upper limit* for a subwoofer crossover point if you like to listen to modern stereo recordings. A crossover point of 150 hz or higher, as recommended by you, can of course be used but this practice should be viewed as being less than optimal. I don't think you'll find too many manufacturers designing systems with a subwoofer crossover point higher than 100 hz these days, and for good reason. No one wants to be FORCED to buy two subwoofers for their stereo system when one might possibly do.
BTW, I wasn't referring to your drawing when I noted that your listening room is square. You have described your listening room as being, basically, an acoustically compromised square in your system profile page. I therefore assumed that this was the room that contained the old "configuration" of yours, mentioned above. Frankly speaking, if your listening room is as problematic as you say it is it wouldn't surprise me that the kinds of sonic nuances I've been talking about here would not be easily noticed.
Edits: 12/05/14 12/05/14 12/05/14 12/05/14 12/05/14 12/05/14
Back in the days when vinyl recordings were the name of the game for most people, bass was summed to mono at 100 hz. So, it used to be more of an OK thing to use a subwoofer crossover point of 100 hz, because doing so would not necessarily degrade stereo imaging and soundstaging.
Now flash forward to the digital age where the cutoff point has been lowered to 80 hz, which corresponds to the point at which bass begins to become omni-directional...
If you listen to modern recordings with a crossover point from mains to a subwoofer higher than 80 hz, you risk shutting out some of the stereo information encoded in your recordings (unless you use two subwoofers that are, preferably, in very close proximity to the associated main speakers).
I agree. I am a big proponent of using multiple subwoofers in a stereo configuration, even with lower crossover frequencies. I currently use two in a stereo configuration in both of my systems, but in the past I've used up to 4 in the system (Geddes approach) with all 4 mono, or in two stereo pairs. I will never go back to using a single sub or a multiple mono configuration unless the crossover frequency is below 50Hz.
You bring up a good point about recordings because a lot of people say you should configure two subs as dual mono rather than stereo, to get more of the benefit of mode cancellation. But as you mentioned, a lot of bass content is already mono, either because it was mixed down to mono or just recorded mono and then panned dead center. For that bass content, there's no difference between dual mono and stereo sub configurations. But as you noted, there is also stereo content in the bass, and you need a stereo configuration to reproduce that.
You say that the placement of subwoofers very close to the main speakers is usually "not recommended" but that would mean that the majority of classically designed tower speakers are extremely compromised designs (from the standpoint of acoustics), since most of them have immovable subwoofers in very close proximity to the other drivers.
Sure they are compromised. There are tradeoffs with every approach. Unless you have a large, acoustically optimum room (either by luck or by design ala Mike Lavigne), full range speakers will almost always have more issues with peaks and nulls in the bass than a properly set up combination of small speakers + subs. But the tradeoff is that the designer of the full range speaker has presumably selected bass drivers that are a good sonic match, and a crossover that ensures a relatively seemless blend. Whereas it can be quite difficult to select subwoofers that are a good sonic match with small standmount speakers, and then optimize their placement, and possibly try different crossover slopes and EQ to blend them properly. I can't say that either design approach is better than the other because it depends on the room, and the speakers, and the experience and acoustics knowledge of the user.
Attempting to keep each of two subwoofers in close proximity to the two main speakers in a stereo system is certainly recommended and is always worth trying before other placement options are investigated, when crossover points approach 80 hz or higher.
I disagree. While placing the subs next to the main speakers may turn out to be the best placement for some systems & rooms, you really need to go through the effort of exploring all possible placements and finding the one that offers the most even response and optimizing the subwoofer settings and even consider eq on the subs. In most cases, especially in small to medium sized rooms, the location of the main speakers is usually not the best place for the subs. In my experience, side wall placement or front wall placement is usually better, but there are no absolutes.
When using only one subwoofer I try to place it about the same distance away from the listening seat as the main speakers, whenever possible.
I agree, especially if the crossover frequency is above 50 Hz. Below that it doesn't matter as the wavelengths are too long. Some would say it doesn't matter up to 80 Hz, but my experience indicates 50 Hz is the threshold for me. Also, if you can do time delay correction, then this isn't required.
Omni-directional sound has a unique sound signature. The ears can sense the shift from omni to uni within the context of a stereo soundstage. 100 hz should represent *the extreme upper limit* for a subwoofer crossover point if you like to listen to modern stereo recordings. A crossover point of 150 hz or higher, as recommended by you, can of course be used but this practice should be viewed as being less than optimal. I don't think you'll find too many manufacturers designing systems with a subwoofer crossover point higher than 100 hz these days, and for good reason. No one wants to be FORCED to buy two subwoofers for their stereo system when one might possibly do.
I don't *recommend* crossover points of 150 Hz or higher. I don't know where you're getting that. What I was saying is that using a crossover point of 150 Hz or higher is a valid design choice that can work if you follow certain design guidelines. And if properly implemented, it can have advantages (e.g. mounting woofers in an infinite baffle can eliminate the front wall 1/4 wavelength null). It's not common in domestic listening rooms because it's way harder to set up and requires knowledge of acoustics and measurement tools, but it is common in recording studios.
BTW, I wasn't referring to your drawing when I noted that your listening room is square. You have described your listening room as being, basically, an acoustically compromised square in your system profile page. I therefore assumed that this was the room that contained the old "configuration" of yours, mentioned above. Frankly speaking, if your listening room is as problematic as you say it is it wouldn't surprise me that the kinds of sonic nuances I've been talking about here would not be easily noticed.
The room is roughly 13x16', but it's not a simple shape which is why I didn't attempt to draw it. The primary acoustic problem caused by the shape is that the first order axial modes associated with the length and width of the room are close together at 35 Hz and 42 Hz. These modes are strong and close enough to interact. Without equalization, bass notes in that range boom. Since I prefer not to use equalization on the main speakers, full range speakers are out. And I need at least one band of PEQ on the subs.
However, like I said in my previous message, the issues I was raising relative to sub placement are not related to the shape of the room. They are only dependent on the location of the subs relative to room boundaries.
Well, it seems as if we actually agree with each other on most points.I will keep on trying to use the lowest possible crossover points, and I will always try to make use of physical alignments whenever possible.
OTOH, I realize that it's not always possible to keep things as simple as that. "As simple as possible, but no simpler" is my motto.
I've been pretty lucky so far in that I've rarely had to deal with an extremely difficult room. I can only hope it stays that way from now on.
Actually, I'd prefer headphones to a loudspeaker system that is dependent upon an obnoxious web of electronic remedies. That said, headphone systems will also become more complex over the next decade or two.
Headphone systems are indeed the future of audio, in large part because of the hassles involved in dealing with acoustical issues. I'm getting ready to meet the future head on.
Edits: 12/05/14 12/05/14
I have some older closed back cans I listen to when I'm working at the computer, Sony CD3000 and Audio-Technica A700 and an OK-sounding Grace 901 amp. One of the things I like best about headphone listening is the clean bass. But I miss the soundstage. Someday I expect to lose my office/spare bedroom to use as a kids bedroom, and then I'll probably let the downstairs system go and get a better headphone rig.
The slower decay times of bass from loudspeakers may actually help with pitch differentiation, at least according to one speaker designer I know of.
Headphone listening has definitely not reached the level of perfection that it is capable of reaching - especially with regards to soundstaging. But the next twenty years or so might change all of that...
Hi and i am not completely sure
I think it is important that all the frequencies arrive in the listening spot at the same time.
For instance ... i could put the bass cabinets frontally ... more or less under the screen
And the satellites quite separated pointing at the listening spot
but i have to delay the bass of course to get time alignment
Of course this is more complicated but i am studying a digital x-over now that should allow for this arrangement
Thanks again.
Kind regards,
bg
I don't want to be in a room very long at 100 Db levels. That's incredibly loud.
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