[jsalk]

This started as an email to a guy who goes by the name of funkmonkey on AVS Forum.  He emailed me about his desire for a great speaker that has bass extension to 30Hz.  His budget was $2000.  When he posted that he recieved an email from me, someone asked if I would post the email on his thread.  Later, someone suggested a re-post it here as well.  So here it is...

funkmonkey -

You asked me to post the contents of an email I sent you a few weeks ago. Sorry it took so long. I took the liberty of editing it somewhat for purposes of clarity. Let's call it...

THE $2000 CHALLENGE

funkmonkey wants a great speaker with bass extension down to a solid 30Hz and has a budget of $2000. This is a real challenge for a speaker designer.

It is possible to design a great speaker that plays to 30Hz. The problem is, it will exceed funkmonkey's budget. Here is why:

Speaker design is the art of balancing trade-offs. The speaker world is controlled by the laws of physics. You can't violate them. So you have to deal with the trade-offs involved.

Before we get going, let me say that there are many "good" $2000 speakers on the market today. But there are no "great" speakers that will play to 30Hz in this group.

First, it is important to realize that 80% of information is found in the midrange. If you don't get this right, you may have a speaker some will find acceptable, but certainly not what we will refer to as a "great" speaker. Herein lies the first trade-off.

Every driver excels in a certain frequency range and no driver can produce great midrange (accurate and detailed) and also produce deep, extended bass to 30Hz.

In a 2-way design, you can select a driver that plays deeper, but you will generally have to give up performance higher up in order to get more extended bass response.

Let's examine how this choice impacted our SongTower design as an example.

One major reason the SongTowers have been so well received, is that they reproduce an exceptionally accurate and detailed midrange and, at the same time, exhibit superb imaging (very deep and wide sound stage). All of these are the result of using a smaller (5") high-quality midwoofer with the extremely good dispersion characteristics a smaller driver can provide. (Most companies will publish FR plots 15-degrees off axis. We have published one at 60-degrees off axis.)

The trade-off is that a 5" driver will not play exceptionally deep. That is an issue we had to deal with and is where the SongTower's transmission line cabinet comes into play.

Unlike a sealed or ported cabinet, the transmission line cabinet is actually part of the speaker rather than an inert box holding the drivers. The energy radiating from the back side of the midwoofer excites air in the transmission line and the "line" is tuned to extend the bass response below where it would be using the same driver with any other type of cabinet. TL cabinets are difficult to design and not all drivers work in them. But, in this case, it works out quite well and many people are surprised by the bass extension of the SongTowers.

But even with the TL cabinet, we can't get to funkmonkey's 30Hz. So what are the alternatives at our disposal?

Well, going with a larger midwoofer in a 2-way design will allow greater bass extension. But the trade-off will be less detail and accuracy in the midrange and far more limited dispersion, resulting in a narrower and shallower sound stage.

In speakers sold at retail, midrange quality is often sacrificed for bass extension. When listening in an audio showroom, people are generally impressed by two things: the amount and extension of the bass and the "air" in the tweeter section. Only after they purchase them and spend some time with them, do they realize that there is a notable lack of midrange quality and relatively poor imaging. You can often add one-note, boomy bass as well.

And that "air" in the tweeter section can also be a problem. Since the larger midwoofer utilized cannot play as high, a tweeter must be chosen that can cross relatively low. In many cases, the top end "air" may result in pushing this larger tweeter to levels of distortion that can contribute to listener fatigue.

There are other alternatives in a 2-way speaker design, but they all involve advanced technology and very expensive drivers. The Seas Excel W18 in our Veracity series speakers is a good example. It uses a very low mass and extremely stiff magnesium cone to generate a great deal of midrange detail. But it is a very expensive driver in comparison to the drivers in the speakers in your price range. And even then, 30Hz is generally not obtainable.

In short, it is highly unlikely that a 2-way design of any consequence could meet the 30 Hz criteria.

Another alternative is a 3- or more-way design. But it is extremely hard to to successfully integrate 3 or more drivers. Integrating drivers, even in a 2-way, is difficult. Only a very small number of 3- or more-way speakers in the world get this right and they are very expensive.

In this situation, finding a combination of 3 or more great drivers and, at the same time, keeping the finished cost under $2000 is basically impossible.

This is especially true if you are designing a speaker that will be sold at retail. An audio dealer needs a 40 - 50% margin in order to carry a product. So the manufacturer must deliver the $2000 speaker to the dealer for around $1000.

In order to do that, and also cover overhead, marketing, R&D, the cost of the cabinets and provide for a profit, the manufacturer can't spend more than about $150 on parts (drivers, crossovers, binding posts, etc.).

To put that into perspective, the Hiquphon tweeters in our SongTowers would already exceed that parts budget. And the woofers in our Veracity HT3's cost more than that each.

Great musical reproduction starts and ends in the midrange. If you don't get that right, you may have an acceptable speaker, but it will not be a "great" speaker. Again, 80% of what you hear is in the midrange. The "you are there" experience most experienced audiophiles look for can be found in the midrange.

That is why we concentrate so hard on midrange performance. It is the foundation of every great speaker design.

Beyond that, you should have detail in the tweeter section as well. The more detail you have here, the better the speaker will re-create the overtone structure of instruments (the level of which is down considerably in volume from the fundamental tones). The more detail you have in the top end, the more "real" instruments will sound. It takes a very good tweeter to provide this detail without causing listener fatigue.

While bass extension is important, if your intention is to design a truly great speaker, you should pursue this only after the midrange and top end are addressed. Because unless you have those two elements well in hand, you will not have a truly great speaker.

So the problem in creating a $2000 speaker with bass extension to 30Hz comes down to accepting some trade-offs that really aren't all that acceptable if you want the best in audio reproduction. You will have to give up a detail, accuracy and imaging, which are attributes that contribute to the "magic" most experienced audiophiles look for.

The bottom line is this: If you are looking for a "great" $2000 speaker with bass extension to 30Hz, your search will likely be in vain. It just doesn't exist.

Well, I could go on forever. But that is probably enough for now.

[Tirade]

Good post Jim. I rarely venture out of the PC forums here at AC but Ive been looking for this mythical creature you describe in your post and I've had no luck. Ive almost accepted my fate and realize to obtain my goal (very similar to funkmonkey's) I'm going to need a sub.

So as a follow up question(s) (and this can be answered via PM), what is the price range that is required to obtain a "great" 2-way if you don't need to go as low as 30hz?

Can it be done for ~$500?

What is the make/break point in frequency where you start to give up too much to make it happen? 40hz? 60hz?

Thanks,

Tim

[BrianM]

30 Hz is just a nice round number.  There's no necessary relationship between "30 Hz" and quality music reproduction.  (Many people in my experience wouldn't know 40 Hz if it bit them, let alone 30.)  The emailer is encouraged to buy the SongTowers and forget about arbitrary numbers.  And anyway I'm sure their in-room response is close enough to the magic 30 mark.

[JoshK]

If I were him, I'd save till he could afford the V3 otherwise "settle" for the Songtowers or if still not satisfied with his choices he should turn to DIY (which isn't saving much if he has to buy all the tools).

Monitors + subs might be another option for him.  Especially if he is a basshead, which it sounds like if he is so hung up on the 30hz number.  I agree with Brian that most do not know the difference between bass and midbass.  What most people think is bass is 80-200hz.  Still 5"ers only can move so much air, constrained by physics if he has a big room, is a headbanger or listens to rap at 95+db. 

[saisunil]

Seems like there is an opportunity not for a not for profit opportunity for the audio community...  

[JoshK]

Seems like there is an opportunity not for a not for profit opportunity for the audio community...  

There is already some DIY designs out there that probably fit the bill.  One doesn't have to look too hard, but discussion of those isn't appropriate on this thread, nor does it really benefit the requester, since it seems implied that he is asking for a commercial offering.

[saisunil]

Jokes aside ... I agree - a good 2 way plus sub would be the way to go.
As mentioned ... it is much harder to make a good three way than a two way let alone at $2k pricepoint.

It is even harder to integrate a three way in a small to mid sized room.

Take the budget to $3k and all of a sudden - you will find some good solutions that can go -3db @ 30 Hz

[martyo]

saisunil, you have a PM

[Toka]

Great, informative post Jim...thanks! 

Possibly dumb question...would it be possible to extend the bass reach in a SongTower (or similar TL design) but using a larger cabinet? Either taller, or "deeper" (not necessarily wider, which seems it would affect imaging).

[DMurphy]

'fraid not.  The ST cabinet is pretty much optimal, period.  What you could do to get closer to the 32 Hz mark (I know he said 30 hz, but 32 Hz is the real break point in that it corresponds to one of the deepest tones produced by any instrument--a big pipe organ) is to substitute the Scan 5" revelator woofers for the Seas, and adjust the cabinet a bit.  I've tried the Scans in the ST cabinet, and they do go deeper and have other virtues as well.  But they also cost $300 more a pair--or $600 for two MTM's.  Just another example of why the $2000 mark is so hard to hit.

[WGH]

What you could do to get closer to the 32 Hz mark (I know he said 30 hz, but 32 Hz is the real break point in that it corresponds to one of the deepest tones produced by any instrument--a big pipe organ) is to substitute the Scan 5" revelator woofers for the Seas, and adjust the cabinet a bit.  I've tried the Scans in the ST cabinet, and they do go deeper and have other virtues as well.  But they also cost $300 more a pair--or $600 for two MTM's.

Sounds like a "Songtower Plus" 

[Boybees]

'fraid not.  The ST cabinet is pretty much optimal, period.  What you could do to get closer to the 32 Hz mark (I know he said 30 hz, but 32 Hz is the real break point in that it corresponds to one of the deepest tones produced by any instrument--a big pipe organ) is to substitute the Scan 5" revelator woofers for the Seas, and adjust the cabinet a bit.  I've tried the Scans in the ST cabinet, and they do go deeper and have other virtues as well.  But they also cost $300 more a pair--or $600 for two MTM's.  Just another example of why the $2000 mark is so hard to hit.

Just for sh*ts and giggles, what about the idea of putting three SEAS 5 inchers in the ST cabinet, as opposed to two (an MTMM design, as it were). That would move more air, no doubt.

BTW, I hosted funkmonkey to listen to my SongTowers, and he's a sophisticated guy (not at all the audio bumpkin that some of the replies in this thread make him out to be). But I essentially asked him the same question: why the focus on 30 hz (The way I put it was: "Do you listen to a lot of pipe organ music?"). I told him that what I feel as "bass" in the music I love (electric bass and kick drum) is well above 30 hz in tone. His response was that he feels there are essential elements of stand-up acoustic bass tone that dip down to 30 hz. That didn't seem right to me, but I didn't argue the point any further.

[DMurphy]

3 instead of 2?  Well, it might move more air, but it wouldn't really go any lower.  And the crossover would be more complex, with some possible adverse repercussions in the lower midrange.  As for the Scan--it would be a Super ST, but that's sort of what the HT2 already is, and it has a ribbon tweet.  The major advantage the Scan ST would have is a smaller footprint, which I kind of doubt would be a major consideration. 

[Paul K.]

Boybees:  If you put 3 drivers into a cabinet optimized for 2 drivers, the cabinet will be undersized and you'll actually end up with a higher F3, even though 3 drivers could move more air than 2 drivers.  This is true for any cabinet, be it sealed, ported, or a TL.  You could make the SongTowers cabinet larger for the two drivers, but it would take a lot more volume to get F3 even close to 30 Hz, if even possible, and there would likely be other tradeoffs you might not want to make.
Paul

[randybessinger]

'fraid not.  The ST cabinet is pretty much optimal, period.  What you could do to get closer to the 32 Hz mark (I know he said 30 hz, but 32 Hz is the real break point in that it corresponds to one of the deepest tones produced by any instrument--a big pipe organ) is to substitute the Scan 5" revelator woofers for the Seas, and adjust the cabinet a bit.  I've tried the Scans in the ST cabinet, and they do go deeper and have other virtues as well.  But they also cost $300 more a pair--or $600 for two MTM's.  Just another example of why the $2000 mark is so hard to hit.

Just for sh*ts and giggles, what about the idea of putting three SEAS 5 inchers in the ST cabinet, as opposed to two (an MTMM design, as it were). That would move more air, no doubt.

BTW, I hosted funkmonkey to listen to my SongTowers, and he's a sophisticated guy (not at all the audio bumpkin that some of the replies in this thread make him out to be). But I essentially asked him the same question: why the focus on 30 hz (The way I put it was: "Do you listen to a lot of pipe organ music?"). I told him that what I feel as "bass" in the music I love (electric bass and kick drum) is well above 30 hz in tone. His response was that he feels there are essential elements of stand-up acoustic bass tone that dip down to 30 hz. That didn't seem right to me, but I didn't argue the point any further.

Did you get any calls from Curtis Chang yet to listen?

[Boybees]

Did you get any calls from Curtis Chang yet to listen?

Not yet, but did notice he was quite active in funkmonkey's AVS thread.

[martyo]

I think different people enjoy listening to music with different types of presentations. I think it is absurd to try to diminish or deny the incredible amount of information between 30 and 40 hz. It's simply there. 2 speakers side by side with comparable midranges and highs, one with an F3 of 30hz, the other with an F3 of 40hz, it's like night and day. Regardless of what instruments lowest notes are, you take away those 10hz and it even changes the character of the music. Does having that extra 10 hz of response bring along another set of challenges, absolutely. Room acoustics become more critical, you need more power, and of course, it costs a lot more. I heard the Songtowers at RMAF. A very nice speaker and with some attributes of speakers costing many times more, quite a bargain. I have HT3's. You know both speakers are in the same family. There are attributes they share. If someone asked me if the HT3's were 3-4 times better, based on the costs, I'd respond it's more than that. Yes the HT3's are more detailed and revealing, but it's those 10hz and the ones below 30 that make them 5+ times better. Yeah and the cabinets. For others, there's no way the HT3's are 3-4 times better than the Songtowers. As Jim said, the midrange has 80% of the material, gotta get that right. But that doesn't imply that the other 20% isn't important. And to these ears, the 80% is altered when the bass of the foundation upon which it rests is missing. For some people it doesn't matter, for others like myself, it has to be there. But to deny it's not there or part of the information................I don't see this like cables, or ss vs. tubes, or digital vs. vinyl, or I guess the "jitter" thread, just personal preferences. There is plenty of information down there, Jim put that big powerful expensive motor in the HT3's for that 10hz and the dynamics and impact that come with those frequencys. I'm done.  

[Boybees]

I think different people enjoy listening to music with different types of presentations. I think it is absurd to try to diminish or deny the incredible amount of information between 30 and 40 hz. It's simply there. 2 speakers side by side with comparable midranges and highs, one with an F3 of 30hz, the other with an F3 of 40hz, it's like night and day. Regardless of what instruments lowest notes are, you take away those 10hz and it even changes the character of the music.

Do you think there is information between 30 and 40 hz on all recordings? Or only on certain ones?

[martyo]

I've never measured anything. I also have almost no classical. I would imagine that yes, any recording I have, if you were able to have a dial that moved that response curve of the HT3's, F3 of 29hz-F10 of 22hz, up 10hz to 39 and 32, it would have quite an effect on the presentation. And the better the recording, the more dramatic the effect would be. I'm not basing this on those numbers because I have measured them, I'm using the speaker makers numbers and then comparing what I do or do not hear with the speakers.

[martyo]

I heard it at RMAF. One time we came in the room the Songtowers were playing. WONDERFUL sound, very nice. And the imagining to my ears might even be a little better than the HT3's, I didn't hear them for that long. But when Jim switched back to the HT3's it was obvious in the low end. My non audiophile wife commented on the bass right away. Fuller more complete sound. I had the Dahlquist DQ10's for many years, manufactures spec of F3 @ 37hz. I was never satisfied. But you have to pay a lot for it if you want to keep the kind of qualities the Songtower already has. For some folks it doesn't matter, for others it does. And until recently in would not have been in my budget.