Frequently Asked Questions

With the LAB SlapBox™, our goal was to create a well-rounded cabinet that would sound good while listening to different genres of music. The SlapBox™ is a driver-specific ported enclosure designed around a specific woofer’s T/S parameters. These boxes are constructed using solid 3/4” MDF, precisely cut and assembled, then sealed using industrial grade sub-floor adhesive. Although the tuning frequency varies among applications, we generally tune our SlapBox™ between 32Hz-34Hz. Tuning in this frequency range provides a well balanced attack of SPL and SQ. You’ll get incredible output and sound quality, without sacrificing low-end extension. The SlapBox™ is available for a variety of sub applications. You choose the carpet color, or get the optional Rhino Linings® bed liner finish. The name says it all. This enclosure really “Slaps”!

- WHAT IS A LAB OEM-Spec™ ENCLOSURE?

Due to the overwhelming requests we've received for manufacturer recommended size boxes, we're proud to offer our line of LAB OEM-Spec™ enclosures. These enclosures use the same quality-built construction, as our SlapBox™, using 3/4” solid MDF (medium density fiberboard). Manufacturers tend to recommend less airspace for their drivers—which allows for better power handling and a smaller footprint. For ported designs, they’re also tuned at a slightly higher frequency than a SlapBox™—which will give a peak in output when listening to bass-heavy music. OEM-Spec™ cabinets are currently available for JL Audio drivers in sealed and ported designs. You can choose the carpet color, or opt for the Rhino Linings® bed liner finish. Smaller size, increased power handling, and manufacturer approval make the OEM-Spec™ enclosure a real winner!

- WHAT IS A LAB PreFab™ ENCLOSURE?

Our LAB PreFab™ enclosures are some of the highest-quality prefabricated speaker boxes on the market. Sufficient for most prefab applications, these woofer cabinets are made with 5/8” MDF. Especially for sealed applications, a PreFab™ box can often times be a quality alternative to a custom-ported one. PreFab™ enclosures are available in either ported or sealed applications. These ported boxes are tuned to about 38Hz, and dual sealed PreFab™ use separate chambers and terminals. Sometimes size does matter; if trunk space is a major factor, you may want to consider a LAB PreFab™ enclosure.

- WHAT’S BETTER? PORTED OR SEALED?

For a given response shape, a sealed box will be the smallest type of enclosure. Although it may not have the best low frequency extension, it's sufficient for some depending on preference and music type. A sealed enclosure is much simpler to design. When using a sealed box, it is difficult to be so far off as to risk damaging the subs. If space is limited, this may be your best choice.

In general, a ported enclosure (aka vented) will have a better low frequency extension for a given response shape (alignment). However, it would require much more airspace, which means a larger enclosure. If you made the box as small as the sealed enclosure, but just ported it to gain the low frequency response, the output would deviate from the desired flat response.

In the early days of car audio, sealed enclosures were much more common. In time, enclosure design progressed and we found that building a ported box could yield great results. With more airspace and a healthy amount of port area, ported boxes could now actually produce a flat response--commonly desired by audiophiles. Of course by nature, a ported enclosure is more efficient, provides more output, and better low frequency extension than a sealed box.

- DOES A PORTED BOX SOUND "BOOMY" OR "MUDDY"?

Because of the many poorly designed ported boxes on the market, many of us are discouraged by the sound quality (or lack there of) of ported. Most of these enclosures are tuned at a higher frequency. They are designed to impress you when you here them in the stores. This means that they are built to produce a large peak at a given frequency (anywhere between 40Hz-60Hz). Again, with today's advancements in speaker enclosure design, we can tune the port to provide the flattest response possible.

- WHAT IS PORT TUNING? WHAT SHOULD MY BOX BE TUNED TO?

Every subwoofer driver has different T/S parameters, which make them unique. In general, tuning at a higher frequency (40Hz+) will give you a "peaky" response. The sub will be noticeably louder in the upper frequency range (45Hz-60Hz), but it would suffer in other areas--especially around 30Hz and below.

Common Tuning Frequencies:

Sound Quality (SQ): 20Hz - 28Hz
Sound Quality Loudness (SQL): 30Hz - 35Hz
Sound Pressure Level (SPL): 40Hz - 80Hz * To avoid low frequencies which would damage the speaker, test tones are played instead of normal music. This type of box is commonly used for SPL competition purposes only.

Tuning low usually flattens out the peakiness, hence giving more consistent output across the sub frequency range (around 30Hz-80Hz). Although, these boxes tend to be larger with bigger ports, they are much more ideal for sound quality.

- WHAT IS THIS "FLAT RESPONSE" YOU SPEAK OF?

In acoustics, we constantly strive for the almighty "flat response". A flat response is an output signal in which fundamental frequencies and harmonics are in the same proportion as those of the input signal being amplified. A flat frequency response would exhibit relatively equal response to all fixed-point frequencies within a given spectrum.

- WHAT EXACTLY ARE T/S PARAMETERS?

The Thiele-Small (T/S) parameters are commonly used by engineers to define the relationship between a speaker and a particular enclosure. But they can also provide some measures describing loudspeaker components that defy marketing interpretation. Here are some of the more useful T/S parameters and what they mean:

Fs: The free-air resonant frequency of a speaker. In general, a lower Fs indicates a woofer that would be better for low-frequency reproduction than a woofer with a higher Fs.
Re: The DC resistance of the driver measured with an ohm meter. This measurement will almost always be less than the driver's nominal impedance.
Le: The voice coil inductance measured in millihenries (mH). The industry standard is to measure inductance at 1kHz. As frequencies get higher there will be a rise in impedance above Re because the voice coil is acting as an inductor. Thus, the impedance of a speaker is not a fixed resistance, but changes as the input frequency changes. Maximum impedance (Zmax) occurs at Fs.
Q parameters: Measurements related to the control of a transducer's suspension when it reaches the resonant frequency (Fs). The suspension must prevent any lateral motion that might allow the voice coil and pole to touch (damaging the loudspeaker). Qms is a measurement of the control from the speaker's mechanical suspension system (the surround and spider). Qes is a measurement of the control from the speaker's electrical suspension system (the voice coil and magnet). Qts is the “Total Q” of the driver. In general, Qts of 0.4 or below indicates a transducer well-suited to a vented enclosure. Qts between 0.4 and 0.7 indicates suitability for a sealed enclosure. Qts of 0.7 or above indicates suitability for free-air or infinite baffle applications.
Cms: The “compliance” of the suspension in a particular speaker. Cms is a measurement of its stiffness measured in meters per Newton.
Vd: The Peak Diaphragm Displacement Volume, or the volume of air the cone will move. It is calculated by multiplying Xmax (voice coil overhang of the driver) by Sd (surface area of the cone). Vd is noted in cc. The highest Vd figure is desirable for a sub-bass transducer.
BL: Expressed in Tesla meters, this is a measurement of the motor strength of a speaker. Think of this as how good a weightlifter the transducer is. The formula is mass in grams divided by the current in amperes. A high BL figure indicates a very strong transducer that moves the cone with authority.
Mms: The combination of the weight of the cone assembly plus the “driver radiation mass load.” The weight of the cone assembly is easy: it's just the sum of the weight of the cone assembly components. The driver radiation mass load is the weight of the air (the amount calculated in Vd) that the cone will have to push.
Xmax/Xlim: Short for Maximum Linear Excursion. Speaker output becomes nonlinear when the voice coil begins to leave the magnetic gap. Although suspensions can create nonlinearity in output, the point at which the number of turns in the gap (see BL) begins to decrease is when distortion starts to increase.
Sd: This is the actual surface area of the cone, normally given in square cm.

- WHAT IS A LAB ENCLOSURE MADE OF?

Unless otherwise stated, our LAB SlapBox™ and LAB OEM-Spec™ enclosures are all constructed using solid 3/4” MDF, precisely cut and assembled, then sealed using industrial grade sub-floor adhesive. Because of high excursion and hefty motors, some higher-end subs call for a reinforced front baffle (1" or 1-1/2" depending). LAB PreFab™ boxes use 5/8" MDF wood, which has been proven to be sufficient.

- WHAT CARPET COLORS OR FINISHES ARE AVAILABLE FOR A LAB BOX?

All our enclosures are wrapped in automotive-grade carpet. We have four standard colors to choose from: Dark Gray, Light Gray, Black, or Tan. For an additional fee, we also offer custom Rhino Linings® truck bed liner finish. Rugged design and cool aesthetics give your box that custom look!

- WHAT KIND OF BOX BUILDING SOFTWARE IS USED TO DESIGN A LAB ENCLOSURE?

To design our speaker cabinets, we use LinearTeam's WinISD box designing software.

- CAN LAB BUILD ME AN ENCLOSURE IF I SUPPLY MY OWN BOX PLANS?

Yes and no. This is handled on a case basis. It’ll usually depend on the size, weight, and design complexity of the enclosure. If you contact us with the box blueprints, we'll let you know if it's possible.

- DO YOU OFFER ENCLOSURE DESIGN SERVICE FOR ME TO BUILD ON MY OWN?

We do offer enclosure design service for those interested. Although not a part of our core business, we do welcome box design service from all our customers. Contact us to inquire about our design services.

- WHAT IS THE DIFFERENCE BETWEEN SINGLE, DUAL, 2-OHM, 4-OHM VOICE COILS?

An ohm is the standard unit of resistance offered to current flow by a conductor, used in electricity calculations. 2-ohm and 4-ohm are the impedance (or resistance measurement of the sub's voice coil). One is not better than the other. The reason for various types of impedances is to give the user the flexibility of running their sub(s) with different type and brand of amplifiers. All amplifiers make max rated power anywhere between 1-ohm mono to 4-ohm bridged. Most subs are also available in either a single voice coil (one + and one - terminal), or dual voice coil (two + and two - terminals). This is only to add flexibility so you can achieve the proper impedance to get max power out of your amplifier.

- HOW DO I SET THE GAIN CONTROL ON MY AMPLIFIER?

Most audio equipment dies for one simple reason. Most people push their equipment beyond their mechanical limits. Whether it’s the amplifier, subwoofer, or full range speakers; clipping is the number one cause of failure. To prevent clipping, you’ll need to properly set your amp’s gain control. There are two ways to achieve this; one is the ‘easy’ way and the other is the ‘hard’ way. The hard way isn’t necessarily difficult, it just requires a DMM (Digital Multi-Meter), test tone signals, and a little bit of instruction following.

Here’s how to set our gain the ‘easy’ way:

Play a typically loud song in your car. Set your head unit’s volume to about 75%. Be sure to wear ear protection.
Starting with the amp’s gain at its lowest setting, slowly increase the gain until you hear clipping from the corresponding speaker. You’ll easily hear the clipping, as it will sound like audible distortion.
Once you've found the clipping point, slightly decrease the gain until you no longer hear the distortion.
Repeat the same process for any additional channels or amps.
The new maximum volume setting on your head unit is now at 75%. To avoid blowing your speaker’s voice coil, never exceed this level.

This is the quick & ‘dirty’ method, which will get you 80% to proper settings. For the other 20%, you’ll need to do it the proper way using a DMM and some test tone signals. We suggest following JL Audio’s tutorial.

- HOW MUCH IS SHIPPING AND HANDLING?

Shipping and handling charges are calculated when you checkout. UPS can not deliver to a P.O. Box, APO, FPO address. Contact us for shipping to HI, AK, or Canada.

- HOW LONG WILL IT TAKE FOR MY ORDER TO SHIP?

Shipping lead times vary. In general, custom-built enclosures such as SlapBox™ and OEM-Spec™ boxes take 1-2 weeks before shipping. Items we usually stock, such as PreFab™ boxes and accessories, typically ship the same business day. Always reference the “Availability” line of the product in question. All tracking numbers are e-mailed upon shipment.

- WHAT FORMS OF PAYMENT ARE ACCEPTED?

PayPal is the preferred payment method for all our transactions. PayPal offers the ultimate in security, and buyer and seller protection in the industry. We can only ship to a PayPal Confirmed address.

PayPal acts like a digital wallet where you can securely store all your payment options, such as your bank account and credit card. When you want to make a payment, you don't have to pull out your credit card or type your billing info every time.

Simply click on the PayPal checkout button, log in to your PayPal account, and select your preferred payment method. PayPal will complete the payment process—without sharing your info with anyone including us.

- DO YOU OFFER INTERNATIONAL SHIPPING?

Currently, we’re only able to ship to the lower 48 U.S. States. UPS can not deliver to a P.O. Box, APO, FPO address. Contact us for shipping to HI, AK, or Canada.

- DO I HAVE TO PAY SALES TAX?

Unless you’re located in California, you are not required to pay sales tax on your order. If you are located in California, we are required to collect sales tax of 7.75% on your purchase.

- CAN I SAVE ON SHIPPING AND PICK UP MY ORDER MYSELF?

We do offer local will-call service if you’re fortunate enough to also be located in Southern California. You will save on all shipping fees. Contact us for more information.

- WHAT IS YOUR RETURN POLICY?

Due to the nature of a custom-built product, all enclosures including (but not limited to) SlapBox™ and OEM-Spec™ enclosure sales are final. We can accept PreFab™ boxes and accessories for refund or exchange. Item must be in new condition and all returns are subject to a 15% restocking fee. Buyers are responsible for all shipping costs, and original shipping is not refundable.