En "liten" feil i post 60. Håper at det blir rett nå og at også bildene blir kopiert riktig.
Hello Elvind,
Thank you for the email. We have many people asking this question. To answer the question first requires a little further evaluation of the SLOB design. The intent of the SLOB is to increase the acoustic loading on the woofer, allowing non-ideal woofers to be used in an OB alignment. This has two effects. First, it reduces the upper end efficiency, which increases the apparent extension of the system. This does not increase the low end efficiency, only reduces the upper end efficiency. Secondly, it increases the resistance which will raise the Qts of the driver. The drawback is lower efficiency, resonances from the slot, and still a need for significant power to move the woofers to high excursion.
To give an idea, if we look at the Altec 416-8B as an example we can see the effects of adding the slot loading to increase apparent mass and suspension stiffness. In the Normalized amplitude Response, the red curve is the driver natural response. The yellow is with the slot loading. Definitely an increase in extension.
Inline image 1
However if we look at the amplitude response with 100W input, we see that there are no actual gains. There is further loss of both low end and high end efficiency. This is the case with any slot loaded open baffle type designs. What this model does not show are the further resonance issues that would be added to the yellow curve based on the size of the slot.
Inline image 2
For open baffles to really work well and have deep extension, the woofers need to be designed with proper motor strength, soft suspension, and ideal parameters. Here you can see how the Dipole15 without any loading compares to TWO 416B in a slot loaded design. For subwoofer use, everywhere below 40hz, the single Dipole15 significantly outperforms the pair of 416B in SLOB design. By 20hz, the Dipole15 is over 5dB more efficient. With the high 15mm one way Xmax, it also produces 6dB more output than the pair of woofers.
That all said, if you really have your heart set on a SLOB type design, you need a woofer with lower Qts and more efficiency that will end up with a Qts between .5 and 1.0 when being slot loaded. You don't want to end up with a Qts that is far too high. The TD15H would be the best option in this alignment. With 14mm Xmax you can still get significant output from the design. With all SLOB designs, make sure you have good power behind this and you will also ideally want EQ to boost the low end.
However, if you are looking for a subwoofer solution that extend very deep without need for EQ and with minimal power, the attached U baffle design would do far better. It requires far less power on the low end. This will also be free from resonances caused by the slot and can play much higher in frequency if needed.
Best Regards,
John
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Acoustic Elegance L.L.C. Phone: 920-328-5206
1825 Mills St
Green Bay, WI 54302 web:
AE Speakers by Acoustic Elegance
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On Mon, Sep 18, 2017 at 9:35 AM, Acoustic Elegance LLC Support <info@aespeakers.com> wrote:
Hello Elvind,
Thank you for your interest in our woofers! Let me first start off by telling you a little about what makes Acoustic Elegance unique before I get to your specific questions. While most companies stock woofers and sell an off the shelf, mass produced product that is often built overseas, at Acoustic Elegance LLC we believe in a more personal approach. Every driver we sell is hand crafted specifically for you, right here at our facility in Green Bay, Wisconsin. Once an order is placed, your production spot is locked into the build queue. We build and ship on a first come, first served basis. This means that the sooner you get your order in, the sooner your woofers will be built. We begin the process right away by machining the steel T-yokes, top plates, and applying the copper Faraday sleeves to the poles of the T-yokes. Our machining phase is very precise, holding to tolerances that are less than the thickness of a human hair. Once the machining is complete, these parts are sent out to a facility in Milwaukee to be zinc plated. Turnaround time at the plating facility can be from 7-21 days depending on their work load. When the parts return, we glue up the motor structure, magnetize it, bolt on the frame, and then begin the final assembly process. During this final assembly we install all the soft parts including the voice coil, spider, and cone/surround assembly. Lead wires are soldered and the cone/surround treatment/damping is carefully applied by hand. Finally, we test each and every driver before packaging and shipping to guarantee the product you are receiving is up to our standards. This personalized approach can take some time however. While we do our best to keep lead times as low as possible, a variety of things can have an effect on the delivery time. Larger OEM orders, occasional backups on machining high quantity of steel parts and lead times given by our parts vendors can affect the overall turnaround time. Currently we are seeing lead times in the range of 2-4 weeks on most products.
I have copied John in this email. He will follow up with you regarding your questions. His email address is
sales@aespeakers.com. Have a great day!
