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Easy Methods to Achieve More Sub Bass: Part 2

I hope everyone is having an enjoyable holiday season this year. I apologize for failing to get an article published on Monday as I usually do. The cold season hit me hard right in time for Christmas. This is Part 2 of ‘More Sub Bass’. In this article I’ll show you some helpful information to understand how sound waves interact, which you can test easily for free!

In the world of car audio there are many topics on which people form their own opinions without looking deeper to find out exactly what’s going on. I’ve been guilty of this very fault, and for this article that applies to the question, “What’s the Best Way to Aim My Subwoofer?”. I was reading about this one night on DIYMA and user 60ndown shared this brilliant web page.

Woofer Box Aiming – by Eddie Runner

Front and Rear Sound Waves In PhaseI highly recommend you read this web page. Eddie Runner explains the science of sound waves just enough so it isn’t overwhelming, and the graphics do a great job for visual learners as well. I read this page at 9:30 p.m. and I had to go turn my sub from front-facing to rear-facing immediately or I knew I couldn’t fall asleep. I had blindly decided to put my sub in at the front of the trunk(for the most storage space) facing the front of the car without any testing. My logic was that the speakers should be facing the listeners. I also knew from past experience that facing the sub to the back would make the trunk lid rattle more.

My cliff notes:

  • Aiming your subwoofers to the front of the vehicle is the worst orientation due to cancellation.
  • Placing the sub box at the back of the trunk facing the back is the best position and orientation.
  • There are BIG differences in audible output as heard by simply moving and rotating your subwoofers.
  • This was the missing link for my car’s disappointing bass.

Don’t forget to bookmark this page and share it with your friends!

Barry Schanz

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Easy Methods to Achieve More Sub Bass: Part 1

In continuation with the plan of providing maximum value for your brief attention span, I’m coming at you with part 1 of a 2 part How-To series. This time the topic is how to get fast results with the goal of better sub bass in the car. I’m not going to tell you to get better equipment. No, this is extremely valuable information for a small expenditure. I spent only $3.47 plus tax on this project!

I do have 2 requirements, the first of which is you must have a subwoofer system. Sorry, you can’t follow the advice I’m going to give you if you’re rocking the factory speakers only. The second requirement is you must have your subwoofer in a sealed box.

Hopefully we’re on the same page now and you’re ready to get to work. This first tip is about an old technique of speaker enclosure treatments called fiberfill stuffing. I have an excellent article for you to read that explains the background and science of what this does to your bass response and why it works.

Make A Small Box Act Like A Larger One With Polyester Fiberfill

My cliff notes:

  • Sometimes we have a limited amount of space for our subwoofer box.
  • Polyester fiberfill, or Polyfill, is one of several products that can be used to make our undersized box perform like a larger box.
  • You want 1 to 1.5 pounds of polyfill per cubic foot.
  • Using this ratio the same box can “sound like” a sealed box that is up to 30% larger.
  • The difference is immediately noticeable on music with deep bass below 50 Hz, with flatter extension to 30 Hz and below(depending on your subwoofer, amplifier, and so on).

Don’t forget to bookmark this page and share it with your friends!

Barry Schanz

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Make A Small Box Act Like A Larger One With Polyester Fiberfill By TOM NOUSAINE

This is posted as a reference for my blog, ‘Easy Methods to Acheive More Sub Bass: Part 1’ . The article is as unaltered as possible* and all references to the author and publishing house are intact.

Make A Small Box Act Like A Larger One With Polyester Fiberfill

The word “FIBER” is turning up in a lot of hip conversations these days you know, the ones that take place in art galleries, bistros, and install bays. In the galleries, they’re talking about the fiber-optic conduits through which compressed digital audio and video will travel when the Intergalactic Superhighway concludes the long and winding road to our homes. In the bistros, they’re talking about the colon-scrubbing glory of fiber-rich delicacies like oatmeal quesadillas and bran flan. But, to us the few, the proud, the mighty Box Builders fiber means dacron-polyester fiberfill, that magic and powerful ingredient that helps deliver maximum bass from a tiny space.

It’s no secret that you can use fiber- fill to make low-end magic; clever installers have been using it for years Take two boxes of the same size and type, insert the same woofer into each one, and stuff one with some fiber-fill the one with the stuffing should kick out lower bass.

In simple terms, it works like this: The fiberfill fools the woofer into thinking that it’s in a larger box (one with more air, or internal volume, in it). than it really is. And, in general, the larger the box, the lower the bass you can get out of it.

Fiberfill stuffing is a popular alternative for people who can’t or don’t want to allot a lot of space for a subwoofer box. A compound or Isobarik configuration, which pairs two woofers in one box, is another popular option, though it has some considerable downsides: For one thing, you have to buy two woofers. There is also a theoretical sensitivity loss (on the order of 6 dB) because you end up with twice the cone mass, though you can cut your losses losing only a few dB SPL by running a pair of the drivers in parallel.

The particulars of fiber stuffing are pretty interesting: The air inside your enclosure actually heats up as your woofer moves, making the air stiffer. (I’m absolutely serious.) When the enclosure is stuffed with fiber, the fibers wiggle, dissipating some of the heat and making the system work as though the box were larger. Theoretically, your woofer/box bass system can act like a system that’s a maximum of 40 percent larger when you’ve latched onto the right stuffing recipe in other words, if you have an enclosure that offers 1 cubic foot (1 ft³ ) of internal volume, in a perfect world a good stuffing job will make it perform like an enclosure that offers 1.4 cubic feet of internal volume.

There are three types of stuffing that are commonly used for this purpose: fiberglass insulation, long-fiber wool, and polyester fiberfill. Fiberfill is the best choice because it doesn’t come loose and fly around and irritate your skin or lungs like fiberglass, it works as well as either of the others, it’s a lot cheaper than wool, and moths hate it. I recently bought five 20-ounce bags of it at $1.99 a pop (a total of 6.26 pounds for $9.95) at Minnesota Fabrics; that turns out to be about $1.60 a pound. You should be able to find some at any fabric store or in the bedding section at friendly stores like K-Mart or Home Depot.

To evaluate the effectiveness of box stuffing, I used an MLSSA analyzer to measure the impedance of three enclosures 5.l-cubic-foot sealed, 1.4-cubic-foot sealed, and 1.4-cubic-foot ported (the port measured 3 inches in diameter and 6 inches in length) with various densities of stuffing. For the sealed boxes, I was able to determine the effective box size as enhanced by the stuffing using the system’s resonant-frequency and Qes values. For the ported box, I compared the tuned frequency of the empty enclosure to the tuned frequency of the stuffed enclosure, using the Speak for Windows computer program; this enabled me to find the effective box size that fit the actual resonant frequency I’d measured.

In each case, the news was good make that very good. With all three boxes, I enjoyed roughly 25 to 35 percent of “space gain” by using stuffing at a rate of 1 to 1.75 pounds per cubic foot of internal volume.

When making system performance predictions, be aware that the Qes figure and, therefore, the Qts figure of the sealed boxes dropped. And with the ported box, the peak of the impedance curve on the lower side of the tuned frequency became heavily damped below the box’s point of resonance. I also found that there is such a thing as too much of a good thing: System resonance (Fsb) rises again, beginning with densities of around 1.5 pounds of stuffing per cubic foot of box volume; this happens because the fibers are jammed so tightly together that they stop wiggling and, consequently, stop dissipating heat.

I also found that stuffing gets less effective as box size increases. The morale: The bigger your box is, the harder it is to fool your woofer.

A few rules of thumb: Stuff small enclosures those with up to about 3 cubic feet of internal volume or less with 1.5 pounds of fiberfill for each cubic foot of internal volume and you should get about a 30-percent increase in box volume without seriously affecting other performance variables. For larger enclosures, add stuffing at a rate of approximately 1 pound per cubic foot and you should get a virtual-space boost of about 25 percent. One thing’s certain: You’ll impress the heck out of your friends at the art gallery and bistro.

*The original of this article was published in the March/April 1995 issue of CAR STEREO REVIEW.

*The images meant to accompany the article were not present.

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Budget Car Audio System – Four Great Shopping Tips

If you’re like most people who want to treat yourself and loved ones to a car stereo upgrade, the price is the biggest concern. You might have said this a few times: “I want the best I can get for my money.” I want to share 4 tips to help shave a few bucks off your bill and save you money in the long term.

1. Decide what about your future stereo you absolutely can’t live without. Everything beyond that is secondary.

Most of the features you will add come from replacing the factory radio. The trend is moving away from bare bones radios, as we see features like built-in navigation, satellite radio, BlueTooth cell phone integration, and more. However, a lot of vehicles can benefit greatly from even a sub-$100 radio upgrade. Often the deciding factor between one model of radio and the next is BlueTooth. If you want to stream music from your phone wirelessly this is a feature you’ll need. Another major point to consider is iPod integration. It can be well worth it to research which brands offer the best iPod interface.

2. If an iPod connection is the only thing you really can’t live without, check if there is an iPod interface kit that’s compatible with your vehicle.

A lot of cars don’t have this upgrade available, but it can save you big money and it doesn’t cost anything to ask a professional installer.

3. Here’s what you should expect if you go in to ask a shop what it will cost to add subs and an amp.

  • You need a way to get an audio signal from your factory radio to your new amplifier. This is done either by running speaker wires directly to the amplifier, or by installing a Line Out Converter(LOC, sometimes called a High Low Converter or HLC). The speaker wire connection(called High Level Inputs) is not available on many amplifiers, but it might save you some money. The LOC will add a modest charge to your bill, less than $25.
  • You’ll need an amplifier installation kit. There are countless brands and sizes out there, but the most important thing is to get the right size wire to match your amplifier. A 4 gauge kit is the most common size needed for 1 subwoofer amplifier and it can usually handle 1 more amplifier for a later upgrade. Expect to pay at least $50 for a good quality kit.

4. Buying online can save you money right now, but do your research before you get your PayPal account or debit/credit card warmed up.

Manufacturers typically have at best a 90 day warranty for goods not sold and installed by an authorized reseller. That great 2 year warranty your buddy got when he took his car to the local car stereo shop is not the same warranty you’ll get for ordering the same gear online. I highly recommend you buy from a reputable local shop and pay them to do the install. Imagine this scenario: You buy an amp from a shop and install it yourself, then you accidentally wire it backwards and it goes up in smoke. As dumb as it sounds it does happen.

You will save yourself a headache in the future if anything goes wrong, and the additional money spent on parts and labor up front will save you money in the long term.

If you’re OK with a short warranty period and you still want to buy online, also check the web site’s return policy. Give them a call or e-mail if  you don’t understand their policy, or if you have questions about what to buy. If you don’t get a satisfactory response, look elsewhere.

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Parametric Equalizer – What is It? Learn This Powerful Tool You Paid For

Example of car parametric equalizer

This video gives the best tutorial on the subject one could ever want. It saves me the effort of trying to and failing to explain the parametric equalizer half as well. Kevin O’Byrne of the YouTube channel 24HzICE is the expert and creator of the video below. What is a parametric equalizer? Who is Kevin O’Byrne and why should I listen to him?

You’re here because you want good sounding music in your car, or any environment, really. If you’ve replaced the radio you almost certainly now have either a graphic equalizer or a parametric equalizer. The parametric equalizer is more powerful than a graphic equalizer, so it’s one thing to consider when deciding between two brands of head units. I’m going to leave it up to Kevin O’Byrne and his excellent 10 minute video to show you the reasons behind this statement.

Now, I’ll introduce our expert, Kevin O’Byrne. I knew nothing about him before I found this video, but he certainly seems like a smart fellow. A brief look at his YouTube channel description, and also his LinkedIn profile, shed some light on the matter. From his YouTube channel ‘About Me’ blurb:

“Former founder editor of Car Stereo & Security magazine (UK). Freelance writer.”

Moving on to his LinkedIn profile, we can see he’s been a professional writer for nearly 25 years, he’s done sales and marketing, product development, proofreading, and more. This man is no slouch when it comes to communicating, and this shows as his 10 minute video is very easy to watch to completion.

Bookmark this page for later if you don’t have 10 minutes to watch this video.


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Upgrading 6.5″ Components – Midrange Woofers

Are you happy with your car stereo? Does it sound pretty good, but you just want a little more? For me, I was really happy with how my car sounded, at least for a while. I had some great times enjoying a wide variety of music on many road trips, but I’d heard better and I got the upgrade bug. I wasn’t getting the impact I wanted to feel from drums and distorted guitars. I’ve listened to a lot of live music and I’ve wanted to recreate that experience in my car.

Whenever a speaker upgrade is in the works there are a few important questions that need to be answered.

  1. What’s my budget?
  2. What do I want from the new speakers that I’m not getting with my current speakers?
  3. How much power do the new speakers need?
  4. Do I need a better amplifier?
  5. Will they fit?
  6. If they won’t fit, what do I need to do to make them fit?

I had been using the CDT Audio CL-62Pro 6.5″ 2-way components, which come with CL-6 midrange speakers. I had already upgrade the crossovers, and I’m happy with how the tweeters sound. What I wanted from the new midrange speakers was a much stronger punch from drums, and I also wanted more crunch and power from distorted guitars.

I already had a good amplifier that is rated for 120W x 2 at 4 Ohms or 240W x 2 at 2 Ohms. This meant I had a wide range of options for speakers when strictly looking at RMS power. However, really power-hungry mids such as the Massive Audio RK6, with an RMS power handling of 250W at 4 Ohms, were not an ideal match.

Since we’re an authorized CDT Audio dealer I knew of several choices of bass-heavy 6.5″ speakers that could replace my CL-6 mids. I’ve been really happy with the quality of everything I’ve gotten my hands on from CDT Audio, and it was an easy choice to stick with this brand. I wouldn’t have to enter personally unknown territory of mixing brands in my front sound stage. Most importantly, if I ran into any issues I could call and ask for help. This did become necessary, which I will get into in a few moments.

The speakers I chose are the HD-6MDVC 6.5″  2 Ohm subwoofers. On paper they looked perfect. Since the impedance dropped in half from 4 Ohms to 2 Ohms I would automatically get more power from my amp. The amp would not need to be replaced. I could get lots of up front bass by using a lower crossover point, and since the outer diameter and mounting depth were identical to the Cl-6 midranges I wouldn’t have to change a thing in my doors. They’re able to play up to 4,000 Hz, and since my EX-560i crossovers use a 3,000 Hz mid/tweet crossover point that was also perfect for my needs.

Don’t skip the sound dampening!

This is critical! Before you spend any money replacing hardware thinking “My speakers have no bass, they must be the problem“, you must treat your doors to get better bass.

What is sound dampening and how do I do it?

Bookmark my Sound Dampening How-To articles and follow along with my photos to learn how to treat your doors and other areas of your car to get better bass.

The New Speakers Are In

Results will vary from vehicle to vehicle, even with the same parts installed with the same techniques. That said, once I had the new HD-6MDVC, I instantly knew there would be some tuning required.  Since I went from a true midrange driver to a subwoofer the frequency response is quite different. I have a 5-band parametric equalizer built into my head unit, which I have been tweaking over the last couple of weeks. I don’t have space to delve into this topic further, so look for another article in the future discussing the tuning I did.

Barry Schanz

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Stronger Midbass for Under $10 – Sound Damping Part 4

Other parts of this article: 1, 2, 3, 4, 5, 6, 7, 8, 9

Welcome back to my Sound Damping How-To article series. I have some awesome tips to show this time, and the supplies you need to purchase are by far the cheapest of anything I’ve demonstrated so far. Results may vary, but I guarantee this is worth your time if you want mega midbass. You will spend less than $10 on this week’s project.

If you recall from my References article, I linked to a virtual gold mine of tips on sound dampening by DIYMA’s expert author, npdang. Here’s a direct link to the discussion thread:

>>> npdang on Simple, cheap, and effective door treatments <<<

Purchase list:

  1. Non-hardening modeling clay, 1 pound (453 g). Cost = $3.57
  2. Rope caulk, comes in a small box with enough to seal 2 house windows. Cost = $5

Why does this improve my midbass?

The concept behind this is based on the behavior of sound waves and how they interact with each other. Speakers create sound waves that radiate outward not only away from the front of the cone, but also away from the back side of the cone. You want to make the back wave unable to get out to the front of the speaker, because this causes cancellation that kills midbass response. If you’re sharp you’ll notice I’m not covering every possible step to reduce this cancellation, but I’m getting ahead of myself now.

Now, I’ll briefly give an overview of the products I had you buy. The non-hardening modeling clay is chosen because it’s easy to work with, it stays in place, it’s highly effective at sealing small gaps, it’s excellent at blocking sound waves, and best of all, IT’S CHEAP! The rope caulk has all of the same advantages plus it’s pre-formed to come off in narrow strips, which is perfect for sealing speakers to a surface.

Time Required

30-60 minutes per door

As you’re applying the clay, keep in mind the clearance needed to keep the speaker from touching the inside of your door panel. You never want the speaker to touch the panel as it’s playing, so if your clearance is tight be mindful of that. Pack that clay in tightly with your finger tips. Enjoy the results!

Barry Schanz

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Reclaiming Lost Midbass Without Breaking the Bank – Sound Damping Part 3

Other parts of this article: 1, 2, 4, 5, 6, 7, 8, 9

If you’ve been following along, this is part 3 of my Beginner’s Sound Damping How-To Series. Previously, I introduced the product I chose to purchase, which is Alpha Damp by Second Skin. I started with a couple of simple projects that made nice instant improvements in cutting back panel noises from vibrations, which makes my time in the car more enjoyable with the tunes cranked up.

What I’m showing you is how to treat the inner door sheet metal. Every vehicle is going to have different doors, and your doors might look very different from mine. Again, the vehicle in these photos is a Saturn sedan.

Products and Materials Needed

  1. Vibration damping mat(Alpha Damp, Dynamat, Stinger Roadkill Expert, etc.)
  2. Sheet metal
  3. Heavy sheers
  4. Gloves
  5. A sharp utility knife
  6. All purpose cleaner
  7. Rags
  8. Self-tapping screws – 1/2″ Install Bay p/n PWHT812 is an example
  9. Battery-operated drill with Philips bit
  10. Rope caulk or silicone sealant with an applicator gun

Time Required

1.5-3 Hours Per Door

Driver’s Front Door

Passenger’s Side Door

If you are mainly a visual learner, browse the photos and note the descriptions I added. There are 2 main things you want to accomplish here.

  1. Put your Alpha Damp onto the metal on any area that rings if you tap it with something hard. Curved areas need less attention than flat surfaces.
  2. Cover and create an air tight seal over any large holes.

This is Crazy! Don’t I Need Those Holes?

In short, yes, but we’re going to make sure it’s not too hard to get in there if need be. The rope caulk isn’t a permanent seal, and the screws come out quickly. I did cover some other smaller holes that would be used to adjust the window track, but I used small pieces of Alpha Damp that I could remove without taking a lot off.

My Saturn uses hooks to hold the inside panel in place, so I couldn’t cover every hole.

Why Bother Doing This?

The speaker uses the door as a sort of enclosure, much like a subwoofer in a box. While the factory leaves nice big holes for a mechanic to get in and fix your roll-down windows and your locks, it’s not good for your music. By sealing off major access holes the door speaker performs better. Midbass frequencies can be greatly improved, which means things like drums, bass guitar, and other really important dynamic parts of your favorite music sound clearer and hit harder than ever before.

Are you ready to get started on Step 1 of the 3 Steps of Acoustic Treatments

Barry Schanz

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Resources for Car Sound Dampening – There’s More Than One Way to Skin a Cat


This week I don’t have any progress to show you all on my Saturn’s sound dampening project, so I thought it would be fun to share some of the fruits of my countless hours of research. Car audio is a real passion of mine, and it’s a topic that can get as complicated as you want to make of it. I have some materials gathered for the next stage of my front door acoustic treatments and I want to link to some sites that show where I got my ideas.

The Gold Mine

Do It Yourself Mobile Audio Forum – This is, in my humble opinion, the BEST car audio forum. As you’ll see when you click the link, their slogan is “Scientific Car Audio – Truth in Sound Quality”. The reason I love this forum is because it has so many members that share my passion for car audio, and as long as you go in with a willingness to read and learn, you’ll fit right in. Whether you’ve just learned to hook up a battery charger or you want to discuss amplifier topologies and crossover points, this forum is for everyone with a good attitude.

Now that I’ve introduced DIYMA and explained why you should pay attention to content posted on that forum, I’ll introduce a How-To article posted by member npdang. npdang is one of the experts on DIYMA, and he is credited with creating the one and only subwoofer to carry the forum name in the model:  “DIYMA12”. I like the article he wrote because it not only has excellent ideas for sound dampening, but the resulting discussion it created spawned many more great ideas.

–> Simple, cheap, and effective door treatments

I’m going to link to one more page, which I just discovered from the previous link. See, I learn something new every day. This is a How-To page from the company RAAMaudio, which is a sound dampening products company catering to the car audio industry. I really like this page because it goes through their recommendations for treating the entire vehicle, broken down into sections as you would work on your own vehicle. There are helpful, clear photos, and the language isn’t overly scientific or technical.

RAAMaudio Home Page–> RAAMaudio How-To

Please visit our Contact Us page to find out a little more about Rubyserv and make use of our contact form to send me an e-mail. You can also contact me on the DIYMA forum under the username trumpet. I hope you enjoyed!

Barry Schanz logo used with permission. RAAMAudio logo used with permission.
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Buzzing Door Panels – Quiet Them with Sound Damping Part 2

Buzzing Door Panels – Quiet Them with Sound Damping Part 2

Other parts of this article: 1, 3, 4, 5, 6, 7, 8, 9

In this article, Part 2 of my beginner’s sound damping How-To series, I will show you how to easily apply a product to your door panels that will greatly reduce buzzing caused by vibrations from your stereo system. For a quick recap, the product is Alpha Damp. This is a Constrained Layer Dampener that consists of a butyl rubber adhesive layer bound to 60 mil foil, which is thicker than foil found on any other comparable product. I don’t sell this product. I’ve used a far inferior sound dampening product in the past and this time I wanted to do it right.

You Showed Me the Product Last Time, What’s Next?

Once again, I am working on a Saturn sedan. The focus of this article is to show what I did to the front door panels. I haven’t yet gotten to the inner door structure, but that will be shown later in a future article. The reason you want to treat door panels every time you do an audio build is because they always need help. Sound dampening matters whether the vehicle is a daily driven commuter car or a high end weekend toy. Auto manufacturers do make efforts at interior noise reduction, but it’s almost never enough.

The Driver’s Side Door Panel

What I did here is wipe down the inside flattest areas of the panel with isopropyl alcohol. You want to prep the area so the Alpha Damp sticks well. Cut the tile into smaller pieces so it’s easier to work with. Focus on the area right by the speaker grille making sure you press down against the curves so you get good adhesion. I wasn’t sure how much Alpha Damp I’d be satisfied with, and I did test the panel on the car with the amount shown and then I added another half tile of coverage. I forgot to take pictures of the final results. It’s perfectly fine to stack pieces to form layers, as this adds mass to the panel.

Another step I took to reduce vibrations is to apply silicone adhesive to particular areas. There was an area of broken plastic on my door panel that I wanted to address, plus I put some silicone between two flat areas of adjoining plastic. I didn’t find this to be worthwhile, as I didn’t notice any noise either before or after the silicone. The smell of curing silicone inside the car isn’t pleasant, so I can’t recommend this.

The Passenger Side Door Panel

I did these panels on different days, and I didn’t use the exact same technique for placing the Alpha Damp. I found it to be quicker to cut the tile into small rectangular pieces, which I overlapped about 50% right around the speaker grille. I used 1 and a half tiles to match what I used on the other panel.

How Did It Work?

Once again, I’m really happy with the effectiveness and ease of application of Alpha Damp. Door vibrations are greatly reduced at the cost of a few hours of time. There’s absolutely no smell. Other CLD products have this same advantage, and it’s a nice change after using a product resembling roof sealant. I still feel vibrations, but from what I understand there’s no practical way to get away from this unless there are no speakers mounted in the doors.

Barry Schanz
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