Low freq. from small drivers? Is it possible

Eldartford, what you describe is virtually impossible, whereas I recognize that you can get deep bass from relatively small cones.

Hi all,

I was forwarded this thread by Michael Wolff, and since my speakers are being discussed here, thought it would be appropriate to throw in my 2c.

Many of the above posts are correct. It is indeed possible to get good bass out of small drivers, and at the same time, as the old saying goes, there is just no substitute for cubic inches (in this case, driver displacement and cabinet volume). The answer to the original question depends almost entirely on the priorities of an individual listener. What is considered a "realistic" volume level and "deep" bass is totally different from one person to the next. Many would consider 90dB at 30Hz to be plenty deep and loud, because the vast majority of listeners will never exceed this. (It's louder and deeper than you think.) Others may not be happy unless they can achieve 110dB at 15Hz! These two things are so far apart as to make discussion utterly meaningless without first defining what you are trying to achieve.

Many of the knocks on the excursion levels of small drivers are substantially solved by the new ultra-linear motor systems developed in the last five or ten years by several manufacturers ("Symmetric Drive" by Scan-Speak, etc). This results in a drastic reduction in IM distortion, and the performance achieved by the Ultimate Monitor would not be possible without this. It still can't break the laws of physics, but if used within its linear excursion limits, will give extraordinary performance regardless of volume level or frequency.

The issue of the extra power required by the BOMB is more of a problem for the amplifier than for the speaker. The reason for this is that there is surprisingly little energy (on a continuous basis) in the deep bass. But when it appears, it can make very heavy transient demands on the power amplifier. The BOMB has a maximum boost of 10dB at 24Hz, which equals a factor of 10 in amplifier power. That is why I recommend relatively high power amplifiers for use with the BOMB. It's not unreasonable-- 100wpc into 4 Ohms is plenty for most applications, provided it's high quality-- but I wouldn't dream of trying to pair this system with a 3W SET amp. The real tradeoff here is that you lose nearly that same 10dB in peak output at the loudspeaker end, in order to stay within the linear excursion limits. As bad as it sounds on paper, this is not a limitation for the vast majority of listeners.

Those who have heard the UM/BOMB system would likely agree not only that the system obliterates every preconceived notion they have about "small speakers", but furthermore, that for "reasonable" listening levels in "normal" sized rooms, they deliver all the volume and bass that most people will ever use, and then some. Will they deliver 110dB at 15 Hz? Not a chance. But that's why they were designed to integrate extremely well with the REL subs and similar sub-bass units.

The bottom line, with this issue and many others, is that there are always compromises. Every time you decide you want to improve performance in one area, you give up something elsewhere. Adding a column of 15" woofers is a great way to make more bass, and it's also a great way to (m)uck up the entire system. There are a hundred things that are of absolutely critical importance in the design of a high-performance loudspeaker, and deep bass extension is one of them.

In the design of the Ultimate Monitor, the goal was always to achieve extraordinary "real world" performance-- that is, to make a small speaker that has virtually no serious flaws when used in average-sized rooms at average volume levels. This is a far, far harder task than is generally realized, and drives the design compromises in directions that most speakers don't take. It's quite simple to design a 3-way ported box speaker that has a wide frequency response, if that's all you're after. It's another thing entirely to make it sound like real music.

I would encourage anyone interested in the technical aspects of speaker design to read the two articles under "tech notes" on our website, http://www.audiomachina.com. They will (hopefully) give a better understanding of the tradeoffs and necessities in any loudspeaker design that aspires to "high fidelity".

Best Regards,
Karl Schuemann
AudioMachina

Onhwy61...Agreed. You can get deep bass from small speakers: even from the 3/4 inch drivers in headphones. However, real LF sound at high volume, such as generated by an organ, is felt as much as heard. It takes large drivers to create the total sensation.

Excellent bass from small 6" woofers.

I was talking about the SF Cremonas. You need to hear this
speaker to know what is possible with small twin 6"
woofers