Saturday, March 9, 2024

Not All Ported Boxes Produce Flabby Bass!


You've heard this: A ported box will never be as tight as a sealed box. The fact that the group delay is so much larger tells you everything you need to know! With a sealed enclosure you get closer to zero group delay!

So while it's true that a ported box will have more group delay than a sealed box, you can design a ported box so the group delay is imperceptible. In other words, since you don't sense it, the ported box will sound just as tight as a sealed box.

In this blog post, we'll talk about what group delay is, why it happens, and why group delay is larger in a ported system. We’ll also discuss some findings from “back in the day” where engineers smarter than me unlocked acceptable group delay numbers!

Let's jump right in:

Wikipedia has this to say about Group Delay:

Group delay describes the time shift of the envelope of a wave packet, a "pack" or "group" of oscillations that travel together, centered around one frequency.

These delays are usually frequency-dependent, which means that different frequency components experience different delays. As a result, the signal's waveform experiences distortion as it passes through the system. This distortion can cause problems such as poor fidelity analog audio…

In other words, group delay is when a signal is distorted through a time shift. This time shift in a subwoofer system happens because air compresses and rarefies. This compression and rarefication happens in a sealed box, too. It’s just that adding a port adds another mass of air to compress and rarefy, which adds complexity.

How does this manifest as distortion? Think about the natural frequency and harmonics generated by plucking a bass guitar. Some of the sounds are going to arrive in your ears later than others. In the case of a sealed enclosure, the lowest frequency arrives last. In the case of a ported enclosure, The frequency centered around port tuning arrives at your ears last.

So how do we control group delay in a ported enclosure? We make sure port tuning and enclosure volume are a good fit for the driver.

But let’s understand something: just because the group delay in a ported enclosure is higher than the group delay in a sealed enclosure, that does not mean your ears can discern it. There is a threshold of audible group delay, and this threshold increases as frequency drops. At 60hz, the threshold of audible group delay is eleven and a half milliseconds. At 50hz, the threshold of audible group delay is thirteen milliseconds, at 40hz, the threshold is 15ms, at 30hz the threshold is 18.5ms, and at 20hz are 25ms.






Controlling Group Delay

The tuning frequency will affect group delay. If we maintain enclosure volume and increase tuning frequency, we will increase group delay.

Increasing enclosure volume will also increase group delay. The opposite is also true. Decreasing ported enclosure volume will also decrease group delay.

Common Mistakes and Solutions

The biggest mistake you can make when you design your subwoofer box is tuning for big SPL centered around one frequency. These will have a distinct ring and a lot of perceptible group delay. Okay, this is only a mistake if you’re building a box for music. If you’re building a one-note wonder for SPL trophies, group delay isn’t an issue. We don’t care about group delay if you’re burping for trophies with limited power.

Another mistake is using a prefabricated ported box whose specs are unknown. Some of these have a relatively high tuning frequency to maximize output. The high frequency will blow past the audible threshold at the high frequency and produce bad sound. This is likely the source of the myth that ported enclosures sound bad.

The easiest way to minimize audible group delay is to use an enclosure volume and tuning recommended by the driver manufacturer. They know the product better than we do, that’s for certain. They also don’t want their audience to say “Yeah, I used their enclosure specs and it sounded awful.” because the next sentence would be something like “Go with another subwoofer driver”

While I want everyone to experiment on their car audio journeys, I do want to point out that people smarter than you and I have provided some guidelines for easy success. In the case of a tight-sounding ported enclosure that romps while sounding as tight as a live acoustic performance, we can have our cake and eat it, too. Just keep the group delay within acceptable guidelines. Remember that acceptable group delay thresholds, measured in milliseconds, will increase as frequency drops and that increasing enclosure size or raising tuning frequency (or both) in our ported enclosures will increase group delay. Conversely, reducing enclosure volume or lowering tuning frequency will reduce group delay. And we can model group delay within WinISD.


Get WinISD Here

Sunday, July 9, 2023

Dev update: made changes to the site that broke it.

I apologize for some inconvenience. I changed node runtimes on google cloud. It's having trouble with one of my packages.

Fixed!!!

Friday, July 7, 2023

Car Audio On Amazon Prime Day 2023!

Prime Day 2023 is July 11 and July 12!

Amazon loves to hype up Prime Day. And we at Subwoofer.Tools love a good deal!

Okay, disclaimer time! As an Amazon Affiliate, Subwoofer.tools will earn a small commission from qualifying purchases on links to Amazon on this page. This helps offset the costs of operating this site at no additional cost to you. We appreciate your support!

Keep in mind these deals will change! Check back often!

Shortcut to all car audio prime day deals!!!

Prime Day Amplifier Sale!

Prime Day Receivers!

Prime Day Speakers!

Prime Day Subwoofers!

Update July 12 1:00pm:

Kicker VK6 6awg wiring kit

Kicker ST7MR SPL Midrange

Update July 12 9:30am:

Pioneer TSA682F speakers!

Pioneer TSA692F speakers!

Pioneer TSA462F speakers!

Pioneer TSD69C speakers!

Pioneer AVH-1550NEX WITH CARPLAY!!

Update July 11 4:00pm:

Memphis Audio VIV3000.1V2 Monoblock subwoofer amplifier

Update July 11 2:00pm:

Kicker PXA-4004 amplifier at PRIME PRICING!

Dual Electronics 7 inch CARPLAY

Memphis Audio M71512 M7 Series 15 inch component subwoofer

Update July 11 1:30pm:

Jensen J1CA7 double din CARPLAY at PRIME PRICING!

Update July 11 12:00pm:

PIONEER TSD10D4 Subwoofer! Ten Inch Pioneer Subwoofer!

Update July 11 9:30am:

NVX VAD11005 5 channel amplifier

NVX VSP69KIT 6x9 V-Series 2-Way Component Speaker System with 25mm Silk Dome Tweeters

NVX NSP68 2-Way N-Series Coaxial Car Speakers with Silk Dome Tweeters

NVX XSP65KIT, 600W Peak (200W RMS) 6.5" X-Series 2-Way Component Speaker System with Carbon Fiber Cones and 25mm Silk Dome Tweeters

Jensen CDR 171 Flip Out LED Screen CD/DVD Player (Kick it OLD SCHOOL)

Update July 11 9:00am:

Rove Dash Cams and Memory Cards!

Atoto S8 Lightning Deal!

Original Post:

We don't know what Amazon has in store for us on Prime Day

We know they leave us hints! 

When I clicked through the Prime Day link in my Amazon app, Amazon said I should follow certain brands. Those brands may have great deals!

The list of suggested brands included Pioneer and Sony. I was PUMPED like I had Real Ultimate Power! If you're in the market for a car audio upgrade, it's hard to beat Pioneer and Sony! 

So here are links to Amazon car audio categories filtered for Pioneer and Sony. 

Hopefully, they put some of these items on sale!

Pioneer Head Units

Pioneer Amplifiers

Pioneer Speakers

Pioneer Subwoofers

Sony Head Units

Sony Amplifiers

Sony Speakers

Once the item goes on sale, it's in a "flash sale" mode, so you must act fast! You'll want to check back a few times during the day!

What's the point of having great sound if your car is dirty? Chemical Guys is having prime day specials on Amazon! Check out the deals they have!!!

Finally: Seasoned Prime Day veterans know about the massive price reductions on Amazon-branded products. These products include, but are not limited to:

Echo Devices and Bundles

Echo Show Devices and Smart Home Bundles

Ring Doorbells, Cameras, Alarms, and Bundles

Fire Tablet bundles

FireTV 4k Streaming Devices

FireTV Smart TVs

Blink Smart Home Security Cameras and Doorbells

Eero Wifi Routers and Systems

If you've been eyeballing these products, now is the time to check them out!

Sunday, April 16, 2023

Database Update: Rockford Fosgate P3 Shallow Subwoofers

We added Rockford Fosgate's Punch P3 subwoofers to the database! Design a subwoofer box for your space using a Rockford Fosgate P3 driver.

Please note: As an Amazon Affiliate, Subwoofer.tools will earn a commission from qualifying purchases. This helps offset the costs of operating this site at no additional cost to you. We appreciate your support!

Rockford Fosgate P3 Slim 12" Subwoofers

Rockford Fosgate P3SD2-12

Design a box for a Rockford Fosgate P3SD2-12

View box designs for a Rockford Fosgate P3SD2-12

Check Amazon for Price and Availability for a Rockford Fosgate P3SD2-12

Rockford Fosgate P3SD4-12

Rockford Fosgate P3 Slim 10" Subwoofers

Rockford Fosgate P3SD2-10

Rockford Fosgate P3SD4-10

Rockford Fosgate P3 Slim 8" Subwoofers

Rockford Fosgate P3SD2-8

Rockford Fosgate P3SD4-8

Links:

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Database Update: Rockford Fosgate Punch P3 Drivers!

We added Rockford Fosgate's Punch P3 subwoofers to the database! Design a subwoofer box for your space using a Rockford Fosgate P3 driver.

Please note: As an Amazon Affiliate, Subwoofer.tools will earn a commission from qualifying purchases. This helps offset the costs of operating this site at no additional cost to you. We appreciate your support!

Rockford Fosgate Punch P3 15" subwoofers

Rockford Fosgate Punch P3D2-15

Design a box for a Rockford Fosgate Punch P3D2-15

View box designs for a Rockford Fosgate Punch P3D2-15

Check Amazon for Rockford Fosgate Punch P3D2-15 pricing and availability

Rockford Fosgate Punch P3D4-15

Design a box for a Rockford Fosgate Punch P3D4-15

View box designs for a Rockford Fosgate Punch P3D4-15

Check Amazon for Rockford Fosgate Punch P3D4-15 pricing and availability

Rockford Fosgate Punch P3 12" subwoofers

Rockford Fosgate Punch P3D2-12

Design a box for a Rockford Fosgate Punch P3D2-12

View box designs for a Rockford Fosgate Punch P3D2-12

Check Amazon for Rockford Fosgate Punch P3D2-12 pricing and availability

Rockford Fosgate Punch P3D4-12

Design a box for a Rockford Fosgate Punch P3D4-12

View box designs for a Rockford Fosgate Punch P3D4-12

Check Amazon for Rockford Fosgate Punch P3D4-12 pricing and availability

Rockford Fosgate Punch P3 10" subwoofers

Rockford Fosgate Punch P3D2-10

Design a box for a Rockford Fosgate Punch P3D2-10

View box designs for a Rockford Fosgate Punch P3D2-10

Check Amazon for Rockford Fosgate Punch P3D2-10 pricing and availability

Rockford Fosgate Punch P3D4-10

Design a box for a Rockford Fosgate Punch P3D4-10

View box designs for a Rockford Fosgate Punch P3D4-10

Check Amazon for Rockford Fosgate Punch P3D4-10 pricing and availability

Links:

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Join the discussions in The SubwooferTools Syndicate Facebook group!

Database Update: Rockford Fosgate Punch P2 Drivers in the Database

We added Rockford Fosgate's Punch P2 subwoofers to the database! Design a subwoofer box for your space using a Rockford Fosgate P2 driver.

Please note: As an Amazon Affiliate, Subwoofer.tools will earn a commission from qualifying purchases. This helps offset the costs of operating this site at no additional cost to you. We appreciate your support!

Rockford Fosgate Punch P2 15" Drivers

Rockford Fosgate Punch P2D2-15

Design a box for a Rockford Fosgate Punch P2D2-15

View box designs for a Rockford Fosgate Punch P2D2-15

Check Amazon for Rockford Fosgate Punch P2D2-15 price and availability

Rockford Fosgate Punch P2D4-15

Design a box for a Rockford Fosgate Punch P2D4-15

View box designs for a Rockford Fosgate Punch P2D4-15

Check Amazon for Rockford Fosgate Punch P2D4-15 price and availability

Rockford Fosgate Punch P2 12" Drivers

Rockford Fosgate Punch P2 10" Drivers

Rockford Fosgate Punch P2 8" Drivers

Links:

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Thursday, March 30, 2023

Database Update: Rockford Fosgate Punch P1 drivers to the database!

We added Rockford Fosgate's Punch P1 subwoofers to the database! Design a subwoofer box for your space using a Rockford Fosgate P1 driver.

Please note: As an Amazon Affiliate, Subwoofer.tools will earn a commission from qualifying purchases. This helps offset the costs of operating this site at no additional cost to you. We appreciate your support!

Rockford Fosgate P1S4-10 Subwoofer

Design a subwoofer box for a Rockford Fosgate P1S4-10

View subwoofer box designs for a Rockford Fosgate P1S4-10

Check Amazon for Rockford Fosgate P1S4-10 price and availability

Rockford Fosgate P1S2-10 Subwoofer

Design a subwoofer box for a Rockford Fosgate P1S2-10

View subwoofer box designs for a Rockford Fosgate P1S2-10

Check Amazon for Rockford Fosgate P1S2-10 price and availability

Rockford Fosgate P1S4-12 Subwoofer

Design a subwoofer box for a Rockford Fosgate P1S4-12

View subwoofer box designs for a Rockford Fosgate P1S4-12

Check Amazon for Rockford Fosgate P1S4-12 price and availability

Rockford Fosgate P1S2-12 Subwoofer

Design a subwoofer box for a Rockford Fosgate P1S2-12

View subwoofer box designs for a Rockford Fosgate P1S2-12

Check Amazon for Rockford Fosgate P1S2-12 price and availability

Rockford Fosgate P1S4-15 Subwoofer

Design a subwoofer box for a Rockford Fosgate P1S4-15

View subwoofer box designs for a Rockford Fosgate P1S4-15

Check Amazon for Rockford Fosgate P1S4-15 price and availability

Rockford Fosgate P1S2-15 Subwoofer

Design a subwoofer box for a Rockford Fosgate P1S2-15

View subwoofer box designs for a Rockford Fosgate P1S2-15

Check Amazon for Rockford Fosgate P1S2-15 price and availability

Links:

Check out the Subwoofer.tools Youtube Channel! Give us a like and a subscribe!

Follow us on Facebook!

Join the discussions in The SubwooferTools Syndicate Facebook group!