How low does the BD15 go with your enclosure

I wonder if I need a seperate sub to extend them down to 20Hz

Thanks

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I wonder if I need a seperate sub to extend them down to 20Hz

You could tune the port lower and EQ the response down to 20Hz but if you want to go that low for HT or things like that then it will probably better to use a sub designed for that purpose.

Why do you want to go down to 20Hz or even lower?

Ciao,

Bert

--
BD-Design - Only the Best!

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Hi Bert,

I am thinking of of setting up for HT and just curious how low would the BD15 low without any modification.

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I am thinking of of setting up for HT and just curious how low would the
BD15 low without any modification.

Then best would be a dedicated subwoofer which you can EQ and tune best for your room without interfering with the main channels. Sub is only noise and moving air and usually rather strong with movies.

Ciao,

Bert

--
BD-Design - Only the Best!

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Hello finecognac,

I recently measured my BD-15 respons with a professional B&K analyser. The -3 dB point is at 29 Hz measured at my optimum listening position. The BD-15 is in a 160-ltr reflex enclosure comparable to the Reference. Below 29 Hz it falls of quite rapidly. Before I used an Eton 581-11 (if I remember correctly) that goes down to 21 Hz according to its specifications (in a 110 ltr. box). There is almost no difference in how deep both units sound (the Eton just wins).

The longest diagonal in my room starting from the speaker cone is just over 6 meter. This gives a lowest room resonance of 28 Hz. It will be very difficult to get a good response down to 20 Hz in such a room. So if your room is larger, you are lucky. Final remark, the Eton and the BD-15 have the same price tag, but the BD-15 sounds MUCH better, i.e. less distortion, more speed and dynamics. :yes:

Kind regards,
Eddie

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Slightly off topic,
There is a solution for extremely low response in a small room.
I am sure you have heard of the rotary sub woofers. Certainly an extreme brute force device. How to reliably measure response and distortion at such low frequencies has me baffled, Perhaps a balloon and a high speed video camera?
Link posted for entertainlent value. This is insane. It makes me laugh, as in a Dr Frankenstein "It's alive" type of laugh... I don't think a valve amp's filaments would last long in this room.

http://bassment.wordpress.com/2006/09/

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If the Bumble bee lifts off, though it should not. This is at topic that even Bert has no vocabulary to baptise as a topic at all.
Where to place this theory?

My Royal Albert Hall examples: Take fan fan cooler and get the feeling. :wacko:

This is to slow down time and make an hour last a year....as you said so wise exampled.

Out of reach to whom made this monster. :fool:

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I wonder if I need a seperate sub to extend them down to 20Hz

Thanks

It is of course interesting to discuss the theoretical "How low does my woofers go"?
And it certainly also have an influence on how "big" you may percieve your sound stage. E.g.: a concert hall.
If the michrophones used for the recording goes low, they will catch any rumble appearing in the concerthall acc. to it's own abilities in the lows.

A studio recording will likely have a cut off around the 20 Hz as many instuments are plugged directly into the mixer etc. and the digital equipment often cuts at 20 Hz as well.

Now having said that, and there are of course much more to be said about it (here I just keep it very simple), it is a completely different case when we talk about "how low" when we place a bass speaker in our living rooms.

We have a box in box situation here.

True is that the cut off is defined by the cabinet and the Fr of the used driver etc; but forgotten is very often the rooms own amplification of the bass.

Most rooms shows a 12 db/oct rise (amplification) from approx. 200 Hz and down. Just check that by meassuring with a mic in you listening position and compare to a close mic meassurement (1 cm from the woofer).

Taking this fact into account a well designed speaker also have to take that fact into account.

There is no point in designing a flat down to 10 Hz speaker. It will sound awefull. Too much bass spoils the musical event like a thick fog of over preassure overlaying the whole sound.

The cab and the driver together should form a relative low Q, meaning a soft roll off, and best is around 12 db/oct roll off to compensate for the similar rise of a given room.

The BD15s are excactly low Q'ed enough to provide linear bass down to the "enough point" in a "normal" room given the right cabinet. (The SWING cabs as example)

I have a room cut off here around 15 Hz. Enough to picture Royal Albert Hall fantastic acoustics and the size of this enourmous hall. And enough to simulate a 10 Hz tone from a crazy synthesizer. The brain will sample down the missing octave and fill in the gap, should the speaker/room be unable to produce sound that low.
Finally: Really low bass are not heard but felt. :cool:

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Hi GC,

For this already very good post of yours, I had -during the reading of it- a response in mind. However, this response was already smacked in by you right at the end :

Finally: Really low bass are not heard but felt.

Okay.
Most probably many people will interpret this as "yeah, correct, the lowest bass can't be heard, but felt only".

As often (or ever :yes I have an explicit opinion on this, which might just not be the "yeah, correct" thing;

At this special version of "the player", existing for just over a week now, three things occur, hence are most obvious :
1. It *must* be the best version out of several I have;
2. It sounds less warm.

Now, I said "three", and the third needs some explanation, or reasoning if you like.
#1 above is important, because it tells that each individual element that can be judged / analyzed in playback, is the best, an THUS I dare to have the conclusion that the things which are *not* judegeable / analyzeable must be better just the same (this is no law, but logic).
And so I say that #2 -it sounds less warm- just must be for the better.

The latter again is important, because this is a subjective matter, and those who know me, know that I like to keep distant of subjectivenesses. And this is exactly why I try to reason that the less warmth must be better, or more real/honest.

Slowly :blush: coming to the point, coincidentally #2 is judged differently by me than my someone else. So there's a dispute here; #1 is clear to us both, but #2 seems "not so good" to the other person while I am very pleased with it. So how to get rid of this subjectiveness, hence what can be found to make it more absolute, thus independent from taste ? (mind you, the taste is allowed to remain, but I like to make things good from theory).

Finally: Really low bass are not heard but felt.

I quote this again, because in here is the key;
The version of the player with the warmer sound, apparently produces more bass. IN THE ROOM. Why ? How ?
Well, because with the colder sounding version you feel the bass ...
And this is #3.

So it is my theory that where "a" version lets feel the bass and not hear it, there is no way that can be worse than another version which makes it audible, but not sensible. The audible thing is what GC perfectly explained ... it is the room doing it to you. This just CAN NOT be better, because this is about reflections and waves coming together, amplifying eachother (yea yea, another epi***e of the standing waves. Sorry).

The downside of it might be, that while a woofer is tuned to cope with in-room responses, hence it decading with a certain rolloff from of a certain (Hz) point, it shouldn't ...

So a question to Bert might be :
Would it be possible to have an alternative filter with less steep (bass) rolloff, in order to test whether it would again make it better at the low end. For that matter Bert, it might come to not only appreciate less warmth, but also to just the absolute sense of less energy at the lower end. And this might even start at not so low as we think ...

What I will do in due time, is setting up a decent measuring environment, where the player (versions) produce the test tones. I mean, this just can be measured ...

Peter

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Hi Peter,

Slowly coming to the point, coincidentally #2 is judged
differently by me than my someone else. So there's a dispute here; #1 is
clear to us both, but #2 seems "not so good" to the other person while I
am very pleased with it. So how to get rid of this subjectiveness, hence
what can be found to make it more absolute, thus independent from taste ?
(mind you, the taste is allowed to remain, but I like to make things good
from theory).

If you are talking about me then you do/should know that I listen to the whole picture as a result. And that is not about taste or being subjective...

Sure, among other things the bass is more tight while then other things show their true nature. Same thing as with the "balls" which you do not seem to like at this moment for the exact same reason...?

Would it be possible to have an alternative filter with less steep (bass)
rolloff, in order to test whether it would again make it better at the low
end. For that matter Bert, it might come to not only appreciate less
warmth, but also to just the absolute sense of less energy at the lower
end. And this might even start at not so low as we think ...

I do not feel the need to change anything to the filter. The amplification of the room is NOT about standing waves, these are extra on top of that at certain frequencies.

What I will do in due time, is setting up a decent measuring environment,
where the player (versions) produce the test tones. I mean, this just can
be measured ...

Cool, then start with that and compare the players with their settings. One thing at the time...

Ciao,

Bert

--
BD-Design - Only the Best!

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Hi Bert,

I do not feel the need to change anything to the filter.

Okay. No problem for me, and just theory anyway (*and* not meant for me myself :cool.

Another fact is, that each time I leave something out to briefen my lengthy posts a bit, there's always someone like you seeing what I left out. So here goes afterall :

The amplification
of the room is NOT about standing waves, these are extra on top of that at
certain frequencies.

Firstly, this is what I made of it :

(yea yea, another e p i s o d e of the standing waves. Sorry).

Can't help it that your swear filter made that unreadable. Anyway, an "e p i s o d e" is different from repeating once more, because I really meant the other chapter, in the same area though;

The standing waves have long gone in my room. Even the current fuzzyness of the USB connection, I do not count to the standing waves phenomenon (but it's close I think). No, instead this must be about individual waves being more tight, and with "individual waves" I mean the in fact individual notes of whatever instrument is playing right beside another instrument (bass area).

[and right here I again scratched another page about theories in fact explaining what I mean :satisfied: ]

Peter

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Bert, again,

If you are talking about me then you do/should know that I listen to the
whole picture as a result. And that is not about taste or being
subjective...

Hahaha. Coincidentally I didn't say you were the one being subjective. However, I pointed out how to approach this in absolute means, and now you disagree with the results. IMHO there is only one way to decently fight this :

Tell me where the theory of feeling bass waves being better than hearing them fails. In the given situation of course.

In the end, I don't urge for an answer, and also this isn't a debate (it wasn't, so it stil isn't). As long as you don't read in all that you are the subjective person (which I don't intend to), everything is okay I think. However, now you must wonder what's going on *then*.
So please understand what I did with all that :

what you perceive could be correct (in it not being compeletely right), and the explanation for that might be a now too steeply rolling off filter.

Now do NOT read *that* as a personal attack to your filter. Because remember, I do not "complain" ... you do. So this is helping you with getting your perceivement better (why ? well, because you are the more experienced), OR let's try to pinpoint what the player is doing wrong.

In the very end it is about getting it better again, with the means we have or can think of.

Might you even think of getting offended, you know me too; I wouldn't dare to even think of getting you close to that. :no:

Peter

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Hi Peter, again... :wink:

Tell me where the theory of feeling bass waves being better than hearing
them fails. In the given situation of course.

I am not the educated and learned professor trying to prove things but merely use my ears and brain to judge. These tell me much more than theory could prove (at this moment).

I do have some knowledge though, grown in time while being occupied with audio. My theorie:

There is the one bass frequency and if that is low then you should not be able to hear it (this is what you are talking about), only felt if strong enough. In music, there is no one bass frequency ever like common for a low distortion signal generator but a fundamental frequency with all its harmonics which tells you what instrument/source is generating that frequency. You feel the fundamental frequency but you also hear its harmonics and the other way around (if these clean fundamental is not present for whatever reason) then the brain "creates" it for you.

If the harmonically low bass frequency is audible reduced and the sense of feeling is still the same then the signal is cleaner or stripped from its harmonics, the bass becomes less "rich"...

Perhaps you are right perhaps you are wrong, do not scratch that page away too soon.

what you perceive could be correct (in it not being completely right),
and the explanation for that might be a now too steeply rolling off
filter.

You are assuming that the response of the bass is rolling of too soon, are you sure? Did you measure this in your room? Which frequencies are we supposed to feel instead of hearing?

As a side note and as you know, my feeling about your present tuned subwoofers is still the same. Generating more "noise" than they should... :yes:

Now do NOT read *that* as a personal attack to your filter. Because
remember, I do not "complain" ... you do. So this is helping you with
getting your perceivement better (why ? well, because you are the more
experienced), OR let's try to pinpoint what the player is doing wrong.

Huh? When did I complain about that? 30Hz is way down deep enough for me!

In the very end it is about getting it better again, with the means we
have or can think of.

Yes, but it does not help much to theorize too much about specific things if the rest isn't more clear, if you ask me that is... :wink:

Might you even think of getting offended, you know me too; I wouldn't dare
to even think of getting you close to that.

I am not offended, I have an easy cure if that might happen. Did you ever get banned? :grin:

Ciao,

Bert

--
BD-Design - Only the Best!

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Hi Bert,

I am not offended, I have an easy cure if that might happen. Did you ever
get banned?

I'm often close to it. :cool:

If the harmonically low bass frequency is audible reduced and the sense of
feeling is still the same then the signal is cleaner or stripped from its
harmonics, the bass becomes less "rich"...

Thank you Bert. This might be a good explanation to keep in mind at further investigating. It wouldn't cope with what;s audible in the higher regions.
Note : But things may be mutually exclusive. My scratched "reasoning" started to have parts of that, hence things extrapolated from the higher regions to the lower, don't seem to be consistent (not for my reasoning, and not for what we hear). So at this point I rather stop with babbling, and instead workout things first.

Otoh, there is too many similarities for the matter of energy and separation.
The whole thing just becomes additionally interesting when we see that a room so-called adds low frequency (what this topic indirectly still is about); Unless under very specialized and controlled conditions like in a horn speaker, this can be about anomalies only.
When I am right at this, we should be glad that a situation only starts (I'm sure of that) to emerge where we just can get rid of those anomalies, and let the waves emerge from the controlled environment instead (out case : the BD15 with cabinet including horn). Your own very good example : do you hear the body coming from the woman her voice at mounting the horn. Well, as you know, when the cabinet is outside, there wouldn't be body whatsoever, so the room does it to you. Uncontrolled ...

Everyone is entitled to disagree, but the less bass I hear at tweaking everywhere but speakers (with the amp as a dangerous option), the more glad I am. Note this is relative to any before situation. I wouldn't like to be without bass obviously !
So far, it never happened that better overal "quality" of sound, didn't come together with less bass.
Stupid theory in my mind is also : when the standing waves have really really gone, them disappearing by means of better quality, there must be a next step, we just couldn't predict. I say (without proof yet) this is it. The bass is going to behave more anechoic with a theoretical infinity of improving, because the walls are there and they remain; the reflections will be less and less pronounced though. The theoretical goal to achieve, is how the speaker behaves in open air, but small problem, it was made for in-room behaviour, counting in room reflections, or my micro collisions coming from that.

When -as you suggest- harmonics are disappearing, or maybe worst : when fundamentals are disappearing and the harmonics remain, this is obviously not good. However, the upper regions prove just the opposite : a whole new worlds of harmonics emerged. Strangely enough, they emerge in mid air and you can pinpoint them (like the "buzzing" of a nylon string). They ARE right, because I kow a guitar. But *I* personally never heard such a thing from speakers and it doesn't even need an Orphean to do it !
Okay ... going offtopic again. Sorry. But I just so much wish to prove that from the one thing we can hear/judge, can be derived that the other thing which is so much more difficult to hear and judge (bass) behaves the same.

This is not about subjtectiveness, this is about "what is good and what is not".
Is in-room response good for a subwoofer ? Yes, it is good for adding low frequencies it in fact does not produce.
No, that same phenomenon is not good for a clear sound. It is about fuzzyness we can't use for music playback. More low and more fuzzy. Both definitly come together.
When this is true, the other way around counts just the same.

The only thing which is required to see that it really can happen that a speaker gets better anechoic behaviour in a room, is the belief that better reproduced sound can take away the standing waves for starters. I think this has been proven enough. Now start to believe in the next step, just in case that is true too. This might mean, try to hear unwanted harmonics in the bad case, instead of missing "good ones" in the good case.

You are assuming that the response of the bass is rolling of too soon, are
you sure? Did you measure this in your room? Which frequencies are we
supposed to feel instead of hearing?

You are waaay too fast. I assumed exactly nothing. I try to find arguments for what we hear, assuming what we hear is right. This is dangerous, because if half of us assume that what we hear is wrong, we'd have to define "wrong".

As you know, my feeling about your present tuned subwoofers is still the
same. Generating more "noise" than they should...

In theory agreed. A bit of a pitty that it counteracts 100% to what we hear, and that subwoofers producing more energy do not produce lower bassy sound. That is the whole point I guess; it works out kind of opposite.
But I know your thoughts about subwoofers, and obviously I agree at them being too slow -in theory- to follow fast transients.
[scratched away again]

Huh? When did I complain about that? 30Hz is way down deep enough for me!

No no, we are mixing subjects here. You complaint is in the area of richness, as you just told. Has othing to do with Hzes. It looks like, however, that there's less richness at the low end, which can easily be translated into frequency. I did that, and is probably not right, out of some context or something else I am not aware of.

Yes, but it does not help much to theorize too much about specific things
if the rest isn't more clear, if you ask me that is... :wink:

Too much is too much indeed. Theorizing might be different from reasoning though. From that follows theory, and from that might follow scientific proof. Next thing is apply it.

Your main mistake is selling me those speakers. :kiss: :swoon:

Peter

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Hi Peter,

and not for what we hear). So at this point I rather stop with babbling,
and instead workout things first.

I fully agree, do something good we all can use and think less out loud... :wink:

Your main mistake is selling me those speakers. :kiss:

That's not a mistake, they will help you faster to arrive where you (and we all) want to be part of... :read:

Ciao,

Bert

--
BD-Design - Only the Best!

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Hi Peter and Bert for that sake too....

I just came back from my bike ride and what happens if I'm absent from the PC just two minutes? P&B :idea:'s and much more.
I thought I should have a sip of wine and just find an empty forum with no posts. Maybe provoke someone or post something interesting never ever posted before, which all who now me by now, rarely see :prankster:

Now I learn, reading your patchwork of intelligence 2-bit-stream brain exchange (Banned by Moderator), that I have to drink herb tea to stay tuned and balance along the line of the thread just to add my 1-bit "way off topic" contribution.

But obviously the tea will do me no good, as tea never does, so just one comment. OK two then or twoandahalf:

1) I my opinion deep rumble "can" be felt and "can" be heard. So the need of "modifying" my first expression "only felt" from the upper post, as I claimed much more could be said about it and I wanted it to be kept simple. (Improves my own understanding of what I'm writing here).
"Felt" because it's proved that our Tympanies etc are not responding to very deep (read=long) waves regardless the amount of energy enclosed.
"Heard" because long waves doesn't stand alone. Never. They always collect harmonics from surroundings and from the physical instrument that created those lows.
We know it from differential tones. No one can hear a 40 Khz tone, right? But we can certainly hear the difference if we apply that 40 KHz tone to an audible 8 Khz tone. It sounds different now.

Of course we dont have to discuss the "felt"-thing as a stand alone subject as everyone can feel a bomb blasts low DC frequency.

If your player, Peter, can dig out that much Felt'n'Heard info from a rip, it is with deep respect I follow your observations in version 1,2 and 3...
It is resolution in the words most extreme interpretation.

Royal Albert Hall, DECCA 2000 recordings, and some very good recorded CD's let us hear the soup of waves fading out and arrives at almost silence, after the orchestras trutti passage Tsunami peak-sound blast wave. In that soup fade-out we hear and feel this, how can I say it, wind blowing? Air preassure changes in the deep deep lows contained in the hall?

I do think though that we only are left with the feeling thing, if no hamonics merged into that soup.

Now to the:

2) Now if I can register the above, not being present in Royal Albert Hall, it must mean that I register it from my speakers, my back-end as well and with my ear/body relationship and it's connection to what's left of my brain.
(D A M N Tea)

But hello boys and girls. We hear that with our ordinary (Sorry Bert) speakers.

I havn't heard any set-up, might it be a SWING like thing or similar added a subwoofer, that benefitet from flat response to DC.
The room thing, you know...not standing waves, which is another phenomenon.

I will claim as in my first post in this thread, that we should aim at a "enough" lows target and leave the brain to do the interpolation of what might be found below 10 Hz or whatever. If we hear the harmonics from those low soupsounds the brain will tell us what was there.

Conclusion:

The GC should dig out as much as it can leaving the felt and heard, shall we say, audible at the same time. Not the one or the either. Both.

The speakers should slowly shut up at lowest 30 Hz for most rooms and that is so elegantly acheived in the SWINGs as they are aperiodically damped bass reflexed/slotted back systems which offer a smooth rool off due to the realised rather low Qt. And then again being incorporated the "anti-behaviour" of "the box in the box" unavoidable build up in the lower bass region in our listening environment.

Thanks God the tea is cold now and I just sipped to it... :whistle:

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Anyway, 26.5 HZ (- 0dB) here. Measured at 1M, 12M long room.
Note : down fireing port. :biglol:
Peter

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