A few months ago, the Long Table contacted nOrh about building subwoofers. This was to be the premiere nightspot in Bangkok. I didn't hear anything for about six months and then I was invited to come and take a look. First of all, this is the nicest club I have ever been to. It should be pointed out that I don't get out much, but none-the-less, I was very impressed by this "no expense spared" night spot.
Bar at the Long Table
I was shown the sound system that was already installed. The existing sound system were ceiling mounted name brand drivers. The main ceiling mounts had a 8 inch woofer and a small tweeter. For the type of speaker that it is, it was high quality but the sound (in my opinion) didn't capture the effort that went into making the Long Table so special.
I brought a pair of FR 4.0s with me. For those of you not familiar with these, the FR 4.0s are the same cabinet as the 3.0 but using a pair of DC-Gold full range drivers. Everyone was impressed and surprised by the sound quality and amount of bass we were getting from the small cabinet.
Not only is the Long Table beautiful, the food is magnificent
We agreed to come back in a few days and take a more detailed look. This time, we brought a pair of DC-Gold 7 inch drivers mounted in the same cabinet as the nOrh 6.9, 7.0 and 9.0. We had not tuned the port so the driver was giving us its full potential. We set up the speakers with a 500 watt per channel rack mounted amplifier. The sound was quite impressive and when we played piano music, the sound was like a real piano. The illusion was quite impressive. I had never had a chance to hear our loudspeakers in such a large space.
The "Long Table"
Originally, we were there to talk about just putting in subwoofers. Based on the performance of the 7 inch DC-Gold full range drivers, I suggested we go with the 10 inch DC-Gold full range. The DC-Gold drivers are capable of producing deep bass down to 30Hz -3dB in a 3/4 to 1 cubic foot cabinet. This is about twice the internal volume of our largest drum speaker and about half the internal volume of our existing subwoofer.
It is always important to nOrh to do more than just put drivers in a box. As we have said many times before, acoustically, the worst design for a loudspeaker would be a cube. A cube has all equal distances and leads to lots of internal reflections. One way to improve from a cube is to design the loudspeaker to be a rectangle which is the second worst design. It is much better to have other than 90 degree angles in loudspeakers so that you can limit parallel reflections - particularly, reflections that fight against the woofer.
Yuth and our engineers have up with a design that I am now calling the "Wall Woofer". The "Wall Woofer" is designed to be mounted near the ceiling. It angles the driver down towards the listener. A pair of Wall woofers will produce flat response form 30 Hz to 19,000 Hz. We believe that this new design will be one of the best designs that combine true high end sound and aesthetics. Getting the drivers off the floor and above eye level will improve the interaction between the room and sound as it will allow the sound to project downward and not directly into furniture. By mounting the drivers higher and angeling them down, we can increase the sweet spot so that more people can enjoy the high-end experience at the same time.
I think it is worthwhile here to talk about subwoofers. I have seen very few really good subwoofers. Producing clean deep bass is not an easy task. Anyone listening to a really good pair of headphones knows that it is possible to produce deep bass with a small driver. Many headphones and ear buds can produce deep bass down to 20 Hz. Of course, the driver in a headphone doesn't have to move a lot of air because of the closed environment it creates inside or around your ears.
Moving air in free space is a lot more difficult. Each driver has its own free air resonate point, fs. This is the point where the driver will resonate in free air. When you put a woofer into a cabinet, the resonate point will change because of the compliance or air stiffness in the box. Each woofer has a set of characteristics that define the amount of cabinet volume that is ideal. Most larger drivers require a large amount of internal space in order to produce the lowest bass. Of course, larger cabinets cost more in materials, cost more to ship and are not always aesthetically ideal. Another issue is that larger woofers encounter more air resistance. The larger the driver is, the less rigid it becomes. At sea level, every square inch encounters a 14.7 pounds per square inch. Therefore, as the diameter of a driver increases, then the resistance it encounters trying to move air increases as well. If you increase the mass of the cone material, to try to make it stiffer, then you need a more powerful motor to drive it. It becomes harder to start and stop.
DC-Gold Audio uses aluminum for their drivers. I have known of several loudspeaker manufacturers that have tried to use aluminum. I remember a company in Maryland years ago called Ezekiel Loudspeakers. Ezekiel Loudspeakers used aluminum drivers. Many people back then swore how great these speakers were. I remember that the aluminum had a seam and I often wondered about the fact that the weight of the speaker would be more around the seam. Looking at the DC-Gold Audio speakers, I have to admire how wonderful the aluminum cones look.
DC-Gold new 7 inch Full Range driver -- note the aluminum cone
Another unique feature of the DC-Gold Audio loudspeakers is that they do not have a spider. They use a Teflon ring and ferro fluid in a patented arrangement that eliminate the need for a spider. I have never had an explanation of the benefits but I can imagine that rather than having a fixed compliance, the compliance of the DC-Gold Audio system would be able to adapt itself more naturally to the work being done by the loudspeaker. I will try to get a full explanation later.
DC-Audio Gold 10 inch driver
The best bass is generally produced with smaller woofers in larger cabinets. Smaller woofers encounter less air resistance than larger drivers so the bass is cleaner and more accurate. nOrh's subwoofers have generally used 8 inch woofers in 2 Cubic Foot cabinets. I have designed subwoofers with 10 inch drivers but the cabinets are generally too large to be practical. I bought a pair of 10 inch Scanspeak woofers that were to be used for my personal subwoofer but I never got around to building them.
I have slowly been working my way through the DC-Gold Audio drivers. I became so impressed with the lowest priced 4 inch full range drivers, that I didn't spend much time trying the others. Recently, I started playing with the 7 inch drivers. I hooked them up to the SE 9 in my office. I can honestly say that this was the best sound I had ever heard coming from the SE 9. The 7 inch drivers are much more efficient than anything I had used to date.
For the Long Table, I suggested that instead of installing subwoofers, we install the 10 inch DC-Gold Audio full range speakers. We would design a cabinet that met our design criteria and create a system that produced flat sound for 30Hz to 20,000 Hz. +/- 3dB. The DC-Audio Gold 10 inch drivers are very efficient of 96dB, meaning that high powered amplifiers are not necessary.
Waterproof speakers
We are quite excited by the DC-Gold Audio loudspeakers. We are excited that by eliminating the need for a crossover, we eliminate the most destructive component in a loudspeaker but we also eliminate what is the most arbitrary part about loudspeaker design as well. Matching a woofer and tweeter together is not just engineering. A loudspeaker designer must spend hours of listening and tuning the crossover to get it just right. No matter how skilled, it is always based on arbitrary decisions by the designer as to what sounds best. The fact that the DC-Gold Audio drivers are waterproof opens up whole new markets where music can be provided. No longer will it be necessary to tolerate those horrible sounding mushroom shaped speakers to hear music outside. People on board boats and ships will be able to enjoy high-end music and feel the excitement of deep bass when watching movies.
The fact that DC-Gold Audio requires smaller cabinets to produce deep bass allows more creative designs than the typical large rectangular cabinet to get deep bass. It makes it possible to deliver big sound from a small box which is good aesthetically and good economically.
The fact that DC-Gold Audio speakers are efficient means they can produce music without having to invest in muscle amplifiers. Even my 9 watt SE 9 drives all the DC-Gold Audio speakers well.
Custom Projects
I would like to thank AffordableAudio.org for their very positive review of the nOrh ACA2b (pronouned ACA Tube). The ACA2b is one of the most affordable preamplifiers on the market. nOrh took a very long time to bring the product to market as we believe the preamp is probably the most overlooked component. While the ACA2b is one of the lowest priced preamps on the market, it features some very unique features for such a budget product. The volume control is made by Alps. The swtiches are platinum plated and the connectors are heavy gold plated connectors.
Affordable Aduio makes the following statements:
"The output stage of the ACA2b is pretty impressive for any price".
"The nOhr ACA2b looks great, it's well built and easy to use".
"Honestly, I would call this wonderful piece either the "Bargain of a Lifetime" or my "Favorie Preamp under $1,000."
The full review can be found here.
I am very greatful that Affordable Audio has taken the time to review our preamp. The simple fact is, nOrh continues to build the best sounding products for the price available anywhere. The SE 6, SE 9 and SE 18 represent the best sound for the money for integrated apmlifiers under $1,000.00.
As many of you have read, I have been confined to my computer and haven't had much time to listen to audio for a long time. I moved a year ago and never had time to hook up my main audio system. My main system is a SE 18, CD 1 and nOrh 9.0. I have long since retired a Plinius system because of the power it uses, heat it generates and space it consumes. I simply don't need to listen to a monster amplifer these days but I do want something that sounds great. The SE 18 fits this bill very well.
I had been evaluating the FR 4 on my SE 9. I had some visitors from Nigeria here in Thailand. I hooked up my main system. One of my guests asked if I had anything smaller and lighter than the nOrh 9.0s. I went upstairs and hooked up the FR 4s to my system. What was interesting is tonally how close the sytsems sounded. The SE 9s sounded fuller and had more bass but the FR 4 sounded remarkably similar.
Both the nOrh 9.0 and the FR 4 are not efficient. Both would benifit from more power than the SE 9 or SE 18 has to offer but the SE 18 was able to provide a very respectible amount of sound from both loudspeakers in a fairly large room (16' x 24').
Sincerely,
Michael C. Barnes
nOrh Loudspeaker Company, Ltd.
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