Good specs for building monitors

[Gohanto]

I'm building my own 2-way speakers in a few months (senior acoustical engineering student, sounded like fun) for both home theater and mixing films. I'm currently looking at a drivers for them. Since I'm using an active crossover, I can eq them pretty close to flat in the room (which I've already treated reasonably well with a couple bass traps and panels).

I'm mainly looking at transient response, frequency response, and dispersion characteristics on drivers, but most of my knowledge comes from people building speakers for music and/or home theater (and the loudspeaker design cookbook). They tend to go for the most accurate and flat response when building there own speakers, but still don't mix anything on them.

Curious if there are any pros here that might let me know (or suggest some sources) about any characterstics I should focus on besides flat response (at both high and low volumes), wide dispersion, and a good transient response on a monitor speaker vs. home theater.

 

[JordanBlock]

If no one here is able to help, you might have some luck on John Sayers' studio design forum.

 

[Gohanto]

If no one here is able to help, you might have some luck on John Sayers' studio design forum.

Cool site, never run across it before.

Thanks :beer:

 

[Petrus]

Why wide dispersion? If you are mixing on them you would be sitting more or less in one spot and with narrow dispersion room reflections are less harmfull.

Many if not most modern monitors (and home spekers also) have a waveguide on the tweeter to make the virtual cone diameter equal to woofer diameter at the crossover point. This gives the spaker smoother transition from woofer to tweeter as the dispersion angle remains constant.

In any case it is more important to aim for constant directivity rather than wide or narrow.

for inspiration:

http://www.genelec.com/ waveguide is NOT a design feature, but an audio feature

http://www.amphion.fi/index.php?sivu=70 good modern speakers with waveguides

 

[Gohanto]

Why wide dispersion? If you are mixing on them you would be sitting more or less in one spot and with narrow dispersion room reflections are less harmfull.

Many if not most modern monitors (and home spekers also) have a waveguide on the tweeter to make the virtual cone diameter equal to woofer diameter at the crossover point. This gives the spaker smoother transition from woofer to tweeter as the dispersion angle remains constant.

In any case it is more important to aim for constant directivity rather than wide or narrow.

for inspiration:

http://www.genelec.com/ waveguide is NOT a design feature, but an audio feature

http://www.amphion.fi/index.php?sivu=70 good modern speakers with waveguides

With most of the narrow dispersion drivers I've heard it always sounds like the sound is getting funneled right at me unnaturally (although great if the speaker is 30+ ft. away). With wide dispersion using proper absorption and diffusion I think it can sound much more natural. If the room blows, narrow dispersion would be better, but likely won't be helpful enough without some kind of room treatment.

Hadn't really noticed the waveguides with those companies before (noticed on B&W's tweeters, but mostly figured they were designed around the internal volume and minimizing internal resonance, but that's a whole nothing thing)

I'd be interested to find out how much that really helps though, since the largest part of keeping constant directivity over the crossover is simply setting the crossover low enough for the woofer to not start beaming. It looks like it would be much more helpful in limiting diffraction.

 

[Petrus]

Waveguide helps in 2 ways: makes tweeter more efficient (horn like loading) and makes the virtual working diameter about the same size as the woofer. The later means that the lower tweeter frequences are more directive keeping the directivity index more constant. Several studies show that constant directivity is very much related to the percieved quality of the speaker. Flat response + constant directivity = guaranteed success! (as long as other things are also ok).

It is not enough to just dig a small depression for the tweeter, the mathematical shape of it is quite exact science and the guys who make these aim for 1/100 mm accuracy or so.

Getting better efficiency from the tweeter also means lower possible crossover points and possibility of making bigger 2-way designs.

I have been following these developements from the sidelines so I can not give exact formulas. Google???

Anders Weckström was one of the first to investigate this phenomenon, unfortunatelly the pages are not in english, but you get the idea: http://www.weckstromspeakers.fi/

Important point: be the directivity narrow or wide, most important is that it is CONSTANT. Maybe the narrow disperision drivers you have heard were not used correctly, i.e. not with same kind of drivers keeping the dispersion constant across the range.

 

[John Willett]

You could always try the Manger driver.

 

[Petrus]

1 more thought: How about doing a 2.5 way system with 2 identical 6-7" woofer midranges, both working from low frequences and one dropping off at around 200 Hz + a good dome tweeter in between with the waveguide/horn thingy. More vertical directivity*, more bass, more efficiency. I am running ADAM S3A:s vertical on low stands aimed 6 degrees up, sound great (with Genelec 7071A sub). They could possibly to sound even better if they had a slight horn for the tweeter, sometimes I could use a bit more oomph from them.

*vertical placement, less refleftions form floor/desk/ceiling.

----------------------------------------
Manger driver = no highs...

 

[Sound Chaser]

I would not worry about specs, but concentrate more on the basics of speaker building--construction, design, tuning and finding complimentary drivers that work well together.
There are basic rules to consider which you may already know. For example, there should not be a lip on the front baffel and a rounded edge is better for the front face plate. Drivers work better in a line array, etc.

The bottom line is a speaker is a moving cone in a magnet and as long as you employ a direct radiator design it is going to spit out a 100 degree image. A wave guided tweeter is a good idea and while it probably is an exact science, I think with a bit of copy/experimentation you will probably see an improvement. Proper construction, balanced drivers and above all the cross over network, active being the best will yield surprisingly good results. Since you have an active system you are miles ahead of the game, especially if your x/over can compensate for phase alignment.

I'm sure that I am going to get an ear full of arguments on my post but, let me say that I have been involved in the speaker building business for many years and while I love the subject--I can't be bothered with arguing about it.
You can also check out the JBL forum--this is one of the highest levels of DIY.
http://audioheritage.org/vbulletin/
p.s. While I follow the thinking and philosophy of the JBL sight, no one is correct in their speaker design theories. Countless debates exist on a very simple science because, audio is the most subjective of fields. But, as Paul Kilpsh said, "ho,hum, another ground breaking technical revelation."

 

[Sound Chaser]

I'm mainly looking at transient response, frequency response, and dispersion characteristics on drivers.... monitor speaker vs. home theater.

In general, studio monitors are simpler, and are designed to radiate driectly to the mixer prior to room reflection, while high quality home speakers are designed to integrate into a furnished untreated room.
2 ways are the current rage because they are simple to design and are generally very accurate. For this reason keep the design simple...that's the key. Avoid a 2.5 split woofer. Extreme bass is not necessarily a good thing when monitoring; it is a desirable thing when listening back. In which case you can add a sub.

As long as you employ a direct radiator design, (which is the simplest and most accurate) you are going to get predictable results because the only variable becomes your drivers. In this respect JBL reign supreme--end of story. They have the best construction, best power compression, best power linearity and by far the best transient response--dynamic realism.
JBL aside, you can still get great results with even cheap speakers that are well constructed. Remember, they are nothing more than a moving cone in a magnet. I prefer paper and have a dislike for kevlar cones, but that's personal.

Most people don't realize it but, rear refection is one of the main flaws in monitoring. Never place your monitors against a wall or in a corner unless that is their design principle. Have you ever noticed how great music sounds outdoors...this is the reason. Reflection is the enemy of accurate response, but conversely it is also what can make a speaker sound pleasing.
Placement is God and while it may be impractical, the biggest single improvement you can make is to soffit mount your monitors, especially if they are larger format designs. Here again the design of your room comes into play as it too should employ a guided wave length, eliminating rear firing or back reflection.

BOTTOM LINE: Listening for pleasure and monitoring for accuracy are two different things. That is why there is a huge gulf between audiophiles who hate JBL and engineers who think audiophiles don't know Jack.

 

[Steve House]

In general, studio monitors are simpler, and are designed to radiate driectly to the mixer prior to room reflection, while high quality home speakers are designed to integrate into a furnished untreated room.
2 ways are the current rage because they are simple to design and are generally very accurate. For this reason keep the design simple...that's the key. Avoid a 2.5 split woofer. Extreme bass is not necessarily a good thing when monitoring; it is a desirable thing when listening back. In which case you can add a sub.

As long as you employ a direct radiator design, (which is the simplest and most accurate) you are going to get predictable results because the only variable becomes your drivers. In this respect JBL reign supreme--end of story. They have the best construction, best power compression, best power linearity and by far the best transient response--dynamic realism.
JBL aside, you can still get great results with even cheap speakers that are well constructed. Remember, they are nothing more than a moving cone in a magnet. I prefer paper and have a dislike for kevlar cones, but that's personal.

Most people don't realize it but, rear refection is one of the main flaws in monitoring. Never place your monitors against a wall or in a corner unless that is their design principle. Have you ever noticed how great music sounds outdoors...this is the reason. Reflection is the enemy of accurate response, but conversely it is also what can make a speaker sound pleasing.
Placement is God and while it may be impractical, the biggest single improvement you can make is to soffit mount your monitors, especially if they are larger format designs. Here again the design of your room comes into play as it too should employ a guided wave length, eliminating rear firing or back reflection.

BOTTOM LINE: Listening for pleasure and monitoring for accuracy are two different things. That is why there is a huge gulf between audiophiles who hate JBL and engineers who think audiophiles don't know Jack.

I concur - I picked up a pair of JBL Pro LSR4328's from Paul over at Resolution Pro Audio a couple of years ago and never looked back. Testing against several other brands, the only monitors I found that was noticably better were K&H's at double the price. And when work is done I find they sound terrific when listening for pleasure as well, as long as the material fed to them is decent to start with, of course. Flawed material sounds flawed on them, as it should since that's why you have monitors.

 

[Gohanto]

BOTTOM LINE: Listening for pleasure and monitoring for accuracy are two different things. That is why there is a huge gulf between audiophiles who hate JBL and engineers who think audiophiles don't know Jack.

That's where I'm a little confused because I know a lot of companies (both home theater and monitor designs) talk about aiming for complete accuracy in their designs. In the highest quality home theater systems, you can hear all the details in recordings. How exactly can a home theater system get designed for showing all the details in a recording without revealing flaws in bad ones?

 

[Noiz2]

You are not seriously believing the PR are you? It's because they only bring out the good details, some movies will be silent on these systems ;~)

 

[Petrus]

There really is no real difference between good hi-fi speakers and good pro monitors: they both aim for the truth. There just is different amount of attention placed on looks and what the marketing thinks best to print on the brochures. There can really be only one goal for both lines of speakers in the end.

Over here many people use Genelecs for better home theatre setups. Up to soffit mounted main monitors depending on the finances...

 

[Sound Chaser]

That's where I'm a little confused because I know a lot of companies (both home theater and monitor designs) talk about aiming for complete accuracy in their designs. In the highest quality home theater systems, you can hear all the details in recordings. How exactly can a home theater system get designed for showing all the details in a recording without revealing flaws in bad ones?

Who said that a home system will not reveal flaws?
What company in the world doesn't say they are designing the most accurate system around?

A home system is designed first and foremost to integrate into a home setting.
Studio monitors generally don't function to potential in a home. They are designed to integrate into an architecturally designed recording facility.
Home theater falls into the middle ground somewhere in between. The room is designed to accommodate good acoustical playback, but it is a far cry from a recording studio.
On the ultra high end, home systems can cost a lot more than pro recording monitors. But, a major part of the cost in a recording system is the room which is specifically designed AROUND the monitor system, in which case the studio ends up costing 10 times even the most expensive home theater.

The major difference as I said is the integration. A studio monitor lines up like a "gun." The imagery is pinpoint accurate to a degree that you can physically see the placement of the image. Shifting your head destroys that alignment. Do you really want to listen to music like that? No, you want the sound to fill the room with a lush full presence.....Great, but you will loose detail, but who cares. That's not what the listening experience is about.
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[Sound Chaser]

There really is no real difference between good hi-fi speakers and good pro monitors: they both aim for the truth. There just is different amount of attention placed on looks and what the marketing thinks best to print on the brochures. There can really be only one goal for both lines of speakers in the end.

Couldn't disagree more.
I have owned 3 recording studios and still have 6 pair of JBL and Tannoy time aligned studio monitors.
How many do you own? How many studio's have you designed and worked in? What schooling and work experience do you have to comment about studio systems.
I would never, ever use a home speaker in a commercial installation. First of all, the dam thing will blow up. Second, I would never be able to layer my tracks correctly because every track would disperse and mask the underlying one.
Studio monitors are built to take commercial punishment. The larger systems use compression drivers...audiophiles hate this Mac Truck mentality.

Some companies like Genelec who make an excellent product are more than useable in a home situation. JBL even incorporates some of their modified commercial line to adapt into multimillion dollar custom home theaters.
But, for the most part excellent systems like B&W, Infinity, and Wilsons who make systems costing $250,000. aim to make the best dam system you can put in your house. My home system Castle Winchesters at 4K a pair fire 360 degrees. How can you mount them in a studio? They sound great for classical music but would last all of 15 seconds before melting down on a rock session.

I like the studio monitor sound, philosophy and build quality. But, if money were no object you can bet I would be getting one of the high end home systems for my home. Why? THEY ARE DESIGNED TO SOUND BETTER IN MY HOUSE.

 

[Petrus]

Couldn't disagree more.
I have owned 3 recording studios and still have 6 pair of JBL and Tannoy time aligned studio monitors.
How many do you own? How many studio's have you designed and worked in? What schooling and work experience do you have to comment about studio systems.

I bow humbly and lower my head in front of your infinite wisdom and profundly deep experience. What a paramount of wisdom have we amongst us! Let my words feel like the buzz of a fly in your golden ears! Hail the new kingpin of audio knowledge!
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There is a section of high end home audio and studio monitoring which overlap. Like midsize Genelec and B&W 800 series, both used in for both home and studio installations. I was thinking along those lines, not about 360 degree sound sprinklers for studios or compression driver living room monsters.

 

[Sound Chaser]

There is a section of high end home audio and studio monitoring which overlap. Like midsize Genelec and B&W 800 series, both used in for both home and studio installations. I was thinking along those lines, not about 360 degree sound sprinklers for studios or compression driver living room monsters.

Very true although I am not aware that B&W fall into that category.

If you want to talk about Pro and home over lapping, the highest expression of Pro is Westlake Audio and they do make consumer versions of their commercial line.
As soon as the use is for home the identical driver combination is rearranged in a line array. Perhaps you can tell me why. Fair question...basic stuff.
However, in all cases whether JBL, Genelec or Westlake, the same rule applies. These are Pro manufacturer's adapting their product for consumer use. Not the other way around. BECAUSE HOME AND STUDIO ARE TWO DIFFERENT MEDIUMS. But, a high end home theater or theaters in general have some of the best acoustics and are ideal for pro gear. Then there is the ultra high end audiophile who builds himself a no cost spared, single seated listening environment. In this example, he's probably listening to Wilsons and couldn't care less about the pro stuff. Pro ain't got nothing on him.

Being pro doesn't mean it is better. In fact there is a good argument to say it is the other way around. Pro and home have different challenges and different applications and thus require different design parameters. Hey, if you build a room in your house that mimics a recording studio--sure go pro. It's designed for that application.

P.S. My humble apologies for upsetting your apple cart. Your statement was ill informed and outlandish.
P.P.S. I wish I had golden ears, or even ears like yours. Mine are tarnished after 35 years in the business. But, hearing is 80% training and applied knowledge.