few questions

[edjosh23]

I'm new to diy, and home audio in general. I've started to build a home theater and want to add a center channel and sub soon.

I have read a lot on threads on here but am not very familiar with ribbon tweeters. Well I really have never heard one, and dont know of any audio shops near me that sell speakers with ribbon tweeters. Obviously this might be difficult, but if possible could anyone explain how ribbon tweeters sound. (remember I am a newbie, not too harsh)

I'm a member of elite car audio and have been referred to a book called the Loudspeaker Design Cookbook to help teach me about enclosure design and passive crossovers. Is this a good book to purchase?

[BillFitzmaurice]

Dickason's book is as good as any and better than most. Ribbons have extremely fast transient response due to their very low diaphraghm mass.

[edjosh23]

I'm going to order the book hopefully tonight. Although I have little experience, do you think it will be difficult for me to build a simple passive crossover?

Are ribbon tweeters good for imaging? From what I have read this is a yes, is that true?

Do ribbon tweeters need a seperate enclosure as to not be effected by other drivers, similar to dome tweeters?

Due to the high effeciency of a ribbon tweeter I'm guessing they are very detailed. Can ribbon tweeters sound staticky?

Thanks,

Josh

[Cal Weldon]

Josh,

A simple passive XO is easy. A good XO is a lot of trial and error.

Ribbon tweeters are good for imaging.

Ribbons are self contained and do not normally need a separate enclosure. What do you mean "like dome tweeters"?

High efficiency? Bill said they have fast transient response. Quite different from high efficiency. They are usually not very efficient.

Staticky? Only if the source is staticky. (I like the word by the way)

Cal

[edjosh23]

Here is my situation, Steely Dan records his albums with very good SQ correct? Especially with a dvd cd. And obviously I shouldn't judge my speakers like this, but when I am very close to my tweeter there is some static.

Is it still preferable for a ribbon to have its on box, this is inside the enclosure if I'm not being clear enough.

"what do you mean like dome tweeters?" Well shouldn't dome tweeters have their own compartment so that other speakers do not interfere with the tweeter's sound?

I have read a few articles about properly building a good crossover and i think i can understand how hard it is.

What do most of you cross over your mids and highs at? What I have read is that you should use test tones to figure out where to set the crossover. But what is an average, for 6.5" or 7" midbass?

Maybe I should search this topic, but what size midrange do you all prefer for a 2way?

Thanks,

Josh

and sorry I am horrible as spelling.

[HeatMiser]

Originally posted by edjosh23
Here is my situation, Steely Dan records his albums with very good SQ correct? Especially with a dvd cd.

Yes, Steely Dan albums are exceptional examples of studio recording. If you like to listen to electric jazz, rock and pop you could hardly do better than Steely Dan for a reference. I understand Donald Fagen's solo album The Nightfly is also a popular reference among recording engineers, when becoming familiar with the sound of a new control room.

And obviously I shouldn't judge my speakers like this, but when I am very close to my tweeter there is some static.

Perhaps you should try and expand on the term "static"; are there actual crackles and pops involved, at low or moderate volumes? If so, I would suspect the electronics before I would the speakers. If you're talking about a certain bright and piercing tone, then maybe it's the speakers.

What do most of you cross over your mids and highs at? What I have read is that you should use test tones to figure out where to set the crossover. But what is an average, for 6.5" or 7" midbass?

It depends on the general type and specific model of both the tweeter and the mid/woofer, and there are other variables including the steepness (order) of the crossover. To name one example of a complicating factor, true ribbon tweeters tend to be sensitive to out-of-band energy so that they often need to be crossed over either higher or steeper (or both) in order to prevent burning them out. As another example, mid-woofers will only play well up to a certain frequency, and this frequency varies, so one must choose a compatible tweeter and crossover design with this in mind. And there are other designs built around wide-range midrange drivers that enable pushing the crossover points far out. Look at the graphs, look at other proven designs with drivers that interest you, research research research.

I am also fairly new to DIY, so keep it in mind that if somebody comes along and disagrees with me they are probably right

[edjosh23]

The static, sounds similar to snow on a tv. It seems to me that it is not necessarily pops or crackles, the only way I can describe it is tv static. The "static" seems to be at the same volume no matter what volume the amp is on. So at lower volumes the static is more predominate, at higher volumes it is much harder to hear, but seems to still be there, at this constant volume.

HeatMiser, complete opposite answer i wanted to hear about midrange drivers

How do I have a steeper roll off? How do I know which cap will have a steeper roll off? (I'm hoping roll off is the right word to use in this situation)

where are good places to order good caps and inductors?

I'm ordering the Loudspeaker design Cookbook 2morrow so after I get it I doubt I'll have as many stupid questions.

Thanks,

Josh

[HeatMiser]

Guess I'll jump in again since nobody more knowledgeable has taken notice yet.

Originally posted by edjosh23
The static, sounds similar to snow on a tv. It seems to me that it is not necessarily pops or crackles, the only way I can describe it is tv static. The "static" seems to be at the same volume no matter what volume the amp is on. So at lower volumes the static is more predominate, at higher volumes it is much harder to hear, but seems to still be there, at this constant volume.

OK, that sounds to me like you're describing background noise that is coming from your amp. Bear in mind that some small amount of audible noise is not unusual if you are really close to your speakers, if it's not intrusive when you sit back and listen as you normally would then I wouldn't worry about it too much. Regardless, changing the speakers probably won't help unless you build a speaker with no tweeter at all.

HeatMiser, complete opposite answer i wanted to hear about midrange drivers

Go look at some of the speakers at www.partsexpress.com or some place like that, check out the response graphs for some midwoofers. You'll see that there is a lot of variation in frequency response, especially at the top end of the graphs. Some of them roll off smoothly at the top, some of them have ragged spikes, and they all start falling off at different frequencies and some more steeply than others. This is just one example of the kinds of things you need to take into consideration when choosing drivers and planning a crossover, because ideally you want to place the crossover in an area where both drivers are still at least somewhat well-behaved. Again, bear in mind that I am not an expert and I am oversimplifying too.

All that said, there are probably lots and lots of 2-way speakers that place the crossover in the 2500-3000 range, but assuming a crossver point in that range will somehow just work would be a tragic mistake. There is usually a lot more to it than that.

How do I have a steeper roll off? How do I know which cap will have a steeper roll off? (I'm hoping roll off is the right word to use in this situation)

The values of the cap determines the crossover frequency, in order to adjust the steepness you add coils and more caps. Google "first order crossovers" and "second order crossovers" to get the idea - a single cap constitutes a first order crossover, which has the shallowest slope of all. There are other attributes which change with the order of the crossover, such as phase shift, which it takes a book to properly explain.

where are good places to order good caps and inductors?

The value of premium caps and coils is a controversial topic which I am not qualified nor inclined to get into.

I'm ordering the Loudspeaker design Cookbook 2morrow so after I get it I doubt I'll have as many stupid questions.

I've heard good things about that book, probably a good move picking it up.

[edjosh23]

Thanks heatmiser

I'm guessing I can do a search on good caps.

I can't think of any more questions right now

Thanks,

Josh

[Cal Weldon]

Originally posted by edjosh23
Steely Dan records his albums

Is that Donald or Walter?
Do you know what a Steely Dan is?
If not, ask your wife/sister/girlfriend. But do it in private.
I'll give you a hint: It's long, cylindrical and makes a buzzing sound.

Sorry, just couldn't resist.

Cal