WAY off topic: Building your own speakers

[glen]

<< Do you know why you barely ever see 12&quot; or 18&quot; drivers in speaker systems >>


A law of physics known as WAF.
Wive Acceptance Factor.
Most folks won't put up with a massive subwoofer the size of a dishwasher or larger in their house. In profession applications, you often DO see larger drivers.

 

[glen]

<< Smaller drivers can sound cleaner for less money and can produce just as much bass. The second reason that speakers like this arent used as often is because it takes a higher quality amp to drive them accurately >>


This is completely backwards.

 

[glen]

<< Although a 18&quot; woffer has the ABILITY to make more bass, it takes more power. A 6-1/2&quot; uses less power but also is limited by it's size because it can only move a certain amount of air. >>

Ability refers to maximun db at a certain frequency. It is a function of x-mas and surface area. Given the same excursion (x-mas)the larger driver wins. The larger driver is also more efficent. This means that in the real world 1 watt makes the 18&quot; louder than the 8.&quot; Do you think that when ALL speaker companies say that their larger drivers are more efficent they are wrong, or lying, or mean somethign else?

 

[maddmax]

I have to agree with Glen's last two posts. On the low end it is all about volume throw under control. A larger diameter(Sd) times the same length of linear travel(X-max) equals greater volume throw. How much throw can you get in an acceptable box size? Best I ever heard was a set of JBL professional monitors powered by a bank of Crown amps in the control room at a recording studio. They used dual 15&quot; woofers.

 

[DiamondFire13]

First of all, the speaker companies have nothing to do whith what you power the woofer with. The power requirements of speakers with bigger woofers are always higher, why is this?? it is because they take more F&amp;*%ing power to sound like the company and the artist intended them to. And if you are stupid enough to belive what any comany says about their own product you are downright stupid. Numbers can make any product look fantastic, i thought that everyone knew that. I personally like the way that smaller woffers sound. I would be willing to bet that most people that can truly apricate a quality speaker would like an array of smaller woofers that generate slightly less bass than a single large driver. If you truly belive that I can take 250 watts from a class AB amp and make cleaner bass with a 18&quot; sub than I can with 4 8&quot; units, I want to hear how this works, give me the physics behind it. Then explain why if I dropped the amp down to 80 watts how it could even move the 18&quot; woffer at all.

P.S. This is all directed at 'Workin and Glen

 

[BoberFett]

Can you feel the love in this room?

 

[outlamd]

And so we see why the whole audio industry is so diversified in it's approach to speaker design. The net result of the entire thread is that there are many ways to achieve the same acoustic goals. Neither is wrong or better. They are different. You may like the sounds of some, and hate the sounds of many. My ears do not hear what yours do, and vice-versa. But it has been a fun and spirited thread. Later!!!

 

[maddmax]

Make that three for Glen. No hostility needed in a good thread.

 

[DiamondFire13]

Sorry guys,

I didnt mean to offend anyone. I just dont see how some of the stuff that Glen was saying is possible. You do see large drivers in certain applications, lice concerts. They are used outdoors, which is completely different, and besides that they dont sound that good, not audiophile quality, just concert-goer quality.

Thats all from me, I will stay out of here from now on Keep posting though, I love to read about audio.

I will change the subject a little too. I am looking into some pretty high quality boockself speakers, can anyone reccomend anything? Preferably accurate, loud, ported for a mid-sized room. I listen to lots of blues, rock and classical.

Thanks

 

[Rigoletto]

Just would like to tell you that the Microsoft DSS80 speakers subwoofer kicks ass! What kind of a design is that?- It uses two subwoofer cones... tells me on the box but that's in the loft!

 

[glen]

<< I am looking into some pretty high quality boockself speakers, can anyone reccomend anything? >>

Alpha-A/VpsbAlpha

 

[glen]

http://www.legacy-audio.com/

 

[maddmax]

DiamondFire, ask that question in the forums at Madisound.com. A better forum for speaker topics. Order a catalog while your there.

 

[glen]

The Subwoofer That Shook The World

 

[MasterMind]

Sound quality and what drivers to use is a argument that no one will ever win. A perfectly balanced system depends on placement of the speakers in relation to the listening distance, the room size (car or home) and the equipment used.

Matching it all up isn't the eaisest thing to do. You should consider tonal quality as well as SPL. A big driver reproduces lower lows but needs more power than smaller drivers. If you're building a box and want alot of punch without multiple amps then several smaller drivers might give you the best balance between SPL and frequency response.

If you want true bass you should have a tuned subwoofer box plus midrange/midbass drivers.

I tried to build a ported sub box once and it was fun but sounded like crap. :frown:

If you really want the most accurate sound possible then go with electrostatics and quit yo' bitchin'.

 

[Workin']

DiamondFire13 - didn't mean to get you all agitated. That usually only happens when someone doesn't really know what they are talking about.

<< Then explain why if I dropped the amp down to 80 watts how it could even move the 18&quot; woffer at all. >>

Ever hear of a little speaker called the Klipschorn? 15&quot; woofer, makes exceptional (though not extremely deep) bass. Makes 102 dB with 1 watt in. All your vast physics knowledge is questionable, because you seem to be unable to see that the amount of air moved is a volume, not an area, and all you are looking at is surface area, completely ignoring excursion, or the 3rd dimension of volume. The K-horn's 15&quot; woofer's excursion is limited to under 1/2&quot;.

To reproduce a given frequency at a given loudness level, all speakers have to move the same amount of air. Whether it is done by a small-diameter, long-excursion cone, or a large-diameter, small excursion cone, it does not matter. You can do the math. So if you want it loud and low, you need a large diameter AND a large excursion.

Since someone asked about what do I know - I have an engineering degree from a prestigious West Coast university (for whatever that's worth), and nearly a decade of real-world experience in vibration analysis and structural design, including FFT analysis of plate- and cone-shaped objects. I am also a trained electronics technician and have troubleshot, repaired, and tested many hundreds of thousands of dollars worth of gear, including high-end audio and data-grade large-screen projection systems. I have been involved with high-end audio since about 1977, and have built my own speakers (which BTW have always had 15&quot; woofers), and helped several of my friend build their own (when I was but a lad). However, I am not a cabinet maker and I had that work done by others.

Well, this has been an interesting little thread, please take it in the spirit of friendly debate, even though it might seem a little rough at times. We can all learn from each other!

 

[glen]

<< Then explain why if I dropped the amp down to 80 watts >>


Ok, if you are not BSing, what instrument did you use to determine the 80 watts?
4 watts will rock the house with an 18&quot; driver. remember - the 18&quot; will barely move compared to the 6.5&quot; and still move more air.

 

[Wolfman35]

Glen &amp; Workin: You guys are missing a KEY Variable in your theory/calculations. It's called VENUE in the audio re-enforcement business. Given an Infinite &quot;Venue&quot; (free air) the theory that larger is better works fine. Factor in a limited room size tho and the theory falls apart. When the &quot;Venue&quot; is limited to a normal room size which is an 8' ceiling (due to sheet rock) and a 13.5' width (due to Carpet) the Length of the listening room should be ~22'. Any speaker builder knows the rule/ratio .6 X 1 X 1.6. If you don't know this ratio you have way too much education and not enough practical experience. Also .. if you have ever tried to actually Power a 15-18&quot; woofer with a 10W amp you would know it just doesn't work in the real world. SPL (the ratio of Db at 1W at 1M) is THEORY used as a guideline for volume Only and is not at all applicable to tonality (which simply cannot be measured or calculated since it is 100% percieved). Most High SPL Woofers are Lousy speakers. Check the SPL on the PSB Alpha drivers. Any driver with an SPL of less than 90 is a very inefficient speaker but thats what most Quality speakers use (mid 80's SPL) because of uhhhh &quot;Tonality&quot;

To sum it up... I could never work a slide rule with my ears.

 

[glen]

Wolf. LOL!

 

[dakotakid]

I just finished building a set of speakers, a kit from a company call Adire Audio adire audio I got the idea from two different home theater forms. home theater forum and home theater talk.

These speakers sound great, well to me at least. You can find a review and pictures of the set that was built by Mike Knapp, he runs home theater talk. Text

 

[Workin']

Wolfman35 I agree with you (and i know glen does, too) that the room is a very important factor in determining sound quality. But to say that it affects which size woofer to choose is total BS. But the real kicker is your un-quantifiable &quot;tonality&quot;. It's a total lie to say that any good speaker will be low efficiency (I think that's what you implied...).

But anyone who knows anything about speaker design knows the &quot;holy trinity&quot; and it's mutually exclusive requirements - bass extension, small enclosure size, and high efficiency. You can get any 2 of the 3 in a design, but never all 3 simultaneously.

And I believe the main goal of &quot;sound reinforcement&quot; equipment is to be loud and indestructible, it only has to kind of sound good.

 

[glen]

<< SPL (the ratio of Db at 1W at 1M) is THEORY >>


No, it not THEORY; it is real world measurments in an anechoic chamber, miked at 1 meter with one watt of power.

 

[Wolfman35]

So Glen, You're saying that Louder is Better?? I know some Stereo salesmen that would Love you!!!!! I agree that SPL is an exacting measurement of efficiency but is it an exacting measurement of quality??? No. Sorry but you just can't measure that. Also remember that it's very uncomfortable to listen to music in an anechoic chamber. Tha Lazy Boy just doesn't fit well. (You have totally missed my point Mr. TI-92)

Workin, What I'm saying is this: Tonality cannot be measured. SPL ratings are simply a number used to match the various drivers in a system so they don't have to be adjusted in the X-Over network as much. Remember ... we're talking about a SubWoofer/Sattelite system here rather than a 2-Way box. I completely agree that Large Venue requirements are &quot;LOUD and indestructible&quot; rather than &quot;Good&quot;. You made my point very well about most 105+ SPL Drivers (especially Woofers at 500Hz and below) If it's a lie ... you seem to agree with it.

All this spirited dis-agreement proves one thing. &quot;If a tree falls in the forest and 100 people hear it ... 99 of them hear it differently&quot;. Now if that tree falls in an anechoic chamber ....... Well even the best Shure Mic doesn't really like music (or Trees) anyway.

 

[MasterMind]

DiamondFire13 What type of enclosure do you want to build? If you want a 3 way monitor I would go with a 12&quot; over a 10&quot;. If you do a sub box then 2 10's would really pack a punch.

Do a little research on enclosures before you decide on the drivers. A 3 way MTM design will give you the 'transparent' quality you're after and decent bass response if you pick the right woofer. If you want to try a design on your own and have the engineering background to pull it off then you might want to check out PMC's loudspeakers. They use a cool design that kicks azz.

BTW, these guys make a EXCELLENT program to help with optimum speaker placement. Visual Ears

 

[gerbz]

Techno-babble aside, what's important is what sounds good in your room with your music.

You can find some great help here:
Audio Asylum

Having built many speakers, I think you're smart going with Scan-Speak and Morel drivers. I think Dynaudio now only sells drivers to oem's.
My favorites, however, are Focal drivers, though their tweeters are hard to handle, they, and their mids and woofers, are extrememly accurate.
I don't know of any american made drivers that are worth your efforts.

Also,
You can't make your boxes too stiff. I use 2 layers of 3/4 inch MDF, lots of screws and glue, and finish them with textured &quot;sand&quot; paint.

You will have tons of felt, for the front panel and box interior,after scavanging a local gasket mfg.

Make your own crossovers with good components and place them in an outboard project box (away from your woofer magnets.) You will definitely want to tweek them.

Yes, add a rear-firing tweeter, but it doesn't have to be top shelf, a good vifa will do.

Vance Dickison's &quot;Loudspeaker Cookbook&quot; and Martin Colloms' &quot;High Performance Loudspeakers&quot; are the 2 best books I've run across.

Take your favorite cd's to audition some Wilson speakers, then go again, and again, and be a pest, but imprint the sonic qualities of a good speaker in your head.

Good Luck.