What do you think of my planned speaker system?

[dustman]

As

You definitely don't know much about speakers and crossovers.

I have been building speakers for many years and some were highly rated by audiophiles, and measured very well in tests.

In my designs, I've always used 2nd and also 3rd Order filters for some of them. I also have the appropriate speaker testing equipment. In my designs, I test each driver and design the crossover components and values based on those drivers' Thiele/Small parameters for best results. That is the fact and it has nothing to do with ego.

As I stated, I'm not trying to design a perfect high end system, I'm trying to make something that will meet my needs, not sound harsh, and at a reasonable cost. All these speakers individually meet those requirements, and based on their spl graphs mesh well. Don't see any reason not to go with the 1st order since I'm not going to be pushing this system to high power levels. Do you have a specific reason why you don't think this setup will work?

 

[TLS Guy]

As

As I stated, I'm not trying to design a perfect high end system, I'm trying to make something that will meet my needs, not sound harsh, and at a reasonable cost. All these speakers individually meet those requirements, and based on their spl graphs mesh well. Don't see any reason not to go with the 1st order since I'm not going to be pushing this system to high power levels. Do you have a specific reason why you don't think this setup will work?

Did you see my last post. Your plan is not how you go about designing a speaker. If you build it, it will sound atrocious. For one thing you have made no allowance for driver level adjustments, and a litany of other oversights.

The crossover is actually the very heart of a speaker, and by far and away the biggest determinant of how it will sound.

There are no splash dash short cuts to this. We are all trying to avoid you wasting money and effort.

Home speaker building is a wonderful hobby and can achieve phenomenal results, but you have to put in the work to understand the science and physics involved.

In short there are no short cuts. Everything down to the last detail has to be planned and calculated.

I can help you, but you have to listen up.

 

[dustman]

It is not helpful being tired of all this. Education is hard work.

I do have to comment that your approach is would require many, many yours of design work. There is a reason why only a few really expensive speakers have large woofers, a mid and a tweeter.

The reason is that you have to deal with a large front baffle, and that causes a lot of reflection from the mid, and especially the tweeter. The other problem is that you have to manage the transition frequency where the speaker becomes a monopole and transitions to an omni pole. This frequency becomes lower the wider the cabinet. This makes it more difficult to manage in the crossover.

The other problem is that you have a very low crossover point from the woofer to the mid. This is not a good idea with passive crossover networks. I never advise a passive crossover point below 350 Hz and preferably not below 400 Hz.

The problem with first order crossover is that the roll off is only 6db per octave, above and below the crossover point. That means that there is considerable overlap of the drivers. This is very hard to manage, and often impossible. The other point I would make, is that all crossovers are the sum of the electrical components and the acoustic responses of the drivers, including, but not limited, to their innate roll offs and their out of band responses. Most speakers usually roll off smoothly on the bottom end, but seldom on the high end. This is because of break up modes above the upper limit of the drivers, that results in horrible peaks. These have to be managed in the crossover design.

If you are set on that speaker, then the woofer should be in its own cabinet, for sure. The mid and tweeter need to be in a much narrower cabinet on top.

The next issue is, you have not considered the power bands of your drivers. One of those Tangband does not have enough power to handle the bandwidth, with a crossover that low. It would require two of those drivers per side. An MTM arrangement would be best with the tweeter between the two.

So I am going to advise you to design a speaker system with better smaller speakers, with a much narrower cabinet, and design and build separate subs. This is a much easier and generally a better and especially a more cost effective approach.

There is a reason there are few really full range speakers, and they cost an absolute fortune.

I have designed such, but it is a really formidable and expensive undertaking.

Designing a speaker correctly is many hours of work.

I am prepared to help you, but I would like you to consider something much easier, and for that matter much better, for you first build.

There was absolutely nothing educational in the others' posts. There is a very definite trend of this kind of behavior on forums of all kinds, it's like being in the comment section on youtube. Anyway, thank you for your mostly constructive response.

If you look at the amplitude graphs the Dayton 15 doesn't really start to peak til 2.5 octaves over the 220 crossover point. The Tang Band has a 3db peak around 4k and 5db peak between 8 and 10k and starts peaking again after 12k. Interestingly, the Dayton tweeter has approximately a 4db dip between 8 and 10k. May encounter slight peaks at 2 and 4k. Of all the drivers I looked at in my price range these seem to mesh much better, and be much tamer than others. Not to mention, I've owned some version of all these and was very pleased with them. Here are the links showing the specs and graphs for the drivers in question:

https://www.parts-express.com/pedocs/specs/295-325-dayton-audio-dc380-8-specifications-46152.pdf

https://www.parts-express.com/pedocs/specs/264-958--tang-band-w5-2143-spec-sheet.pdf

https://www.parts-express.com/pedocs/specs/275-070-dayton-audio-dc28f-8-silk-dome-tweeter-specifications.pdf

As far as power handling, these 5" mids have more power handling(and lower fs) than the dual 3" tang bands I currently have crossed over at 200hz, 1st order, and I have cranked these many times and had no problems, and surprisingly, not much distortion. Is there some other reason that crossing over low passively can have deleterious effects?

The woofers will be in separate cabinets, the mid and tweeter in their own small cabs, flush mounted.

I am not after perfection, just good, and I don't have a particularly refined ear. After building quite a few speaker systems, most of the early ones with prefabbed 12db crossovers, and some with custom 12db crossovers, built to recommendation, I have had a number of disappointments. The system I have now with dual 3" TB bamboo drivers and dayton sub crossed over at 200hz is the most pleasing yet, although not good off axis and lacking great high highs.

 

[dustman]

Why? Specifically...

 

[TLS Guy]

There was absolutely nothing educational in the others' posts. There is a very definite trend of this kind of behavior on forums of all kinds, it's like being in the comment section on youtube. Anyway, thank you for your mostly constructive response.

If you look at the amplitude graphs the Dayton 15 doesn't really start to peak til 2.5 octaves over the 220 crossover point. The Tang Band has a 3db peak around 4k and 5db peak between 8 and 10k and starts peaking again after 12k. Interestingly, the Dayton tweeter has approximately a 4db dip between 8 and 10k. May encounter slight peaks at 2 and 4k. Of all the drivers I looked at in my price range these seem to mesh much better, and be much tamer than others. Not to mention, I've owned some version of all these and was very pleased with them. Here are the links showing the specs and graphs for the drivers in question:

https://www.parts-express.com/pedocs/specs/295-325-dayton-audio-dc380-8-specifications-46152.pdf

https://www.parts-express.com/pedocs/specs/264-958--tang-band-w5-2143-spec-sheet.pdf

https://www.parts-express.com/pedocs/specs/275-070-dayton-audio-dc28f-8-silk-dome-tweeter-specifications.pdf

As far as power handling, these 5" mids have more power handling(and lower fs) than the dual 3" tang bands I currently have crossed over at 200hz, 1st order, and I have cranked these many times and had no problems, and surprisingly, not much distortion. Is there some other reason that crossing over low passively can have deleterious effects?

The woofers will be in separate cabinets, the mid and tweeter in their own small cabs, flush mounted.

I am not after perfection, just good, and I don't have a particularly refined ear. After building quite a few speaker systems, most of the early ones with prefabbed 12db crossovers, and some with custom 12db crossovers, built to recommendation, I have had a number of disappointments. The system I have now with dual 3" TB bamboo drivers and dayton sub crossed over at 200hz is the most pleasing yet, although not good off axis and lacking great high highs.

I think I can help you design a very decent speaker with two out of the three of the drivers,.

We absolutely need to use two mids, for not not only power handling, but because we need to to raise the sensitivity to pair with the woofer.

The tweeter is not nearly sensitive enough, so another needs to be selected.

We should absolutely cross from woofer to mids at 400 Hz and not 200 Hz.

Do you want me to go ahead and work on this? Basically your design concept has promise, but needs to be integrated into a total design.

 

[Hetfield]

I just would like to say I wish I had the nerve and was able to build a speaker. Unfortunately I can barely tie my shoes. So I commend you for trying and getting the info needed to be successful.

Sent from my Pixel 4 XL using Tapatalk

 

[dustman]

I think I can help you design a very decent speaker with two out of the three of the drivers,.

We absolutely need to use two mids, for not not only power handling, but because we need to to raise the sensitivity to pair with the woofer.

The tweeter is not nearly sensitive enough, so another needs to be selected.

We should absolutely cross from woofer to mids at 400 Hz and not 200 Hz.

Do you want me to go ahead and work on this? Basically your design concept has promise, but needs to be integrated into a total design.

I guess I don't understand how you reached your conclusions. The amplitudes seem to match up pretty well at and near the crossover points. Can you explain how and why the response graphs aren't telling me the whole story? Wouldn't raising the crossover point on the woofer bring that nasty peak more into play? Is the reason for the increased crossover frequency purely to decrease power level to the mid?

 

[TLS Guy]

I guess I don't understand how you reached your conclusions. The amplitudes seem to match up pretty well at and near the crossover points. Can you explain how and why the response graphs aren't telling me the whole story? Wouldn't raising the crossover point on the woofer bring that nasty peak more into play? Is the reason for the increased crossover frequency purely to decrease power level to the mid?

No, they are not close enough. You need some headroom for the loss of the passive components and need ability for fine tuning the voltage to each speaker.

Low crossover with passive crossovers are very bad news, due to multiple issues, especially the behavior of the high value of the resistance and reactivity of the components involved. You have to take in the rising impedance of the woofer especially. This results in the value of the inductors in the low pass section being much higher than you think. Otherwise the woofer never cuts off. In addition it puts far too much power to the midrange speaker, limiting the power response. I can easily suppress those break up woofer modes with a cross at 400 Hz. I have done this for sixty years, and I know how to do this.

By the way pretty near in speakers is not good enough ever. 2 to 3 db deviation in response in the wrong place can be very audible.

 

[dustman]

So you are saying that because of the rising impedance the relationship with the inductor changes as frequency rises, resulting in not achieving the attenuation that was expected? In this case, there wouldn't be enough attenuation of the woofer to mitigate the large peak in response starting at 1500hz? If you raise the crossover frequency then would this not just exacerbate the problem? By power response you mean differences in off axis response, lobing? How would you go about suppressing breakup modes, with a notch filter?

I don't want to be told what to do, I want to understand the principles of what is going on so I can analyze it myself and make my own conclusions and decisions based on my needs/desires.

 

[Mark E. Long]

Those are really nice popcorn holders …………….;-)

 

[ryanosaur]

Start with these two:

Introduction to Loudspeaker Design: Second Edition: Murphy, John L.: 9780966377347: Amazon.com: Books

Introduction to Loudspeaker Design: Second Edition [Murphy, John L.] on Amazon.com. *FREE* shipping on qualifying offers. Introduction to Loudspeaker Design: Second Edition

www.amazon.com

Designing, Building, and Testing Your Own Speaker System with Projects: Weems, David: 9780070694293: Amazon.com: Books

Designing, Building, and Testing Your Own Speaker System with Projects [Weems, David] on Amazon.com. *FREE* shipping on qualifying offers. Designing, Building, and Testing Your Own Speaker System with Projects

www.amazon.com

Then move on to this:

Speaker Building 201: Ray Alden: 9781882580453: Amazon.com: Books

Speaker Building 201 [Ray Alden] on Amazon.com. *FREE* shipping on qualifying offers. Speaker Building 201

www.amazon.com

Then this:

Loudspeaker Design Cookbook: Dickason, Vance: 9781882580330: Amazon.com: Books

Loudspeaker Design Cookbook [Dickason, Vance] on Amazon.com. *FREE* shipping on qualifying offers. Loudspeaker Design Cookbook

www.amazon.com

 

[dustman]

I own 2 of those books, though its been a long time since I read them. I need interpretation. And as far as this thread goes I could use less vague answers.

As an example: in the impedance graph you see that at 1khz the impedance is 20 ohms, coupled with the 6.0mh inductor the resulting amplitude response is such and such, and as the impedance continues to rise the result is such and such, and this is why. So, as we reach the woofers amplitude peak the combined amplitude of the woofer and mid is such and such, etc... And this is why...

Without examples, principles and the why of it all, it is useless, unless I already have a deeper education in the matter, in which case I wouldn't need to be here.

 

[Swerd]

I accounted for any peaks in response in the upper frequency range of the woofer and mid, it appears that anything of consequence is at least two octave above the crossover point so should be well attenuated.

I checked the values for the crossover components with several different online calculators and they all agreed with each other within a pretty narrow margin.

The problem with any of those calculators is that they assume a fixed impedance value. The nominal impedance of the DC380-8 15" woofer is said to be 8Ω, but the impedance vs. frequency curve (blue trace) shows how much it rises as the frequency increases. Because you plan to use a 1st order crossover, you have to consider the impedance values as much as two octaves above your planned crossover frequency of 200 Hz. At 400 Hz, impedance is about 12Ω, and at 800 Hz it's nearly 20Ω. Instead of an online calculator, it would be better to use a computer application that makes use of the impedance data in this curve. Parts Express supplies that data in the FRD/ZMA file.

That large 6 mH inductor coil, you mentioned is meant for the woofer low-pass filter, right? Because it has a lot of wire, the DC resistance is about 1.5Ω. If you selected a 6 mH coil because you assumed a constant impedance of 8Ω, it won’t work as you plan because the woofer’s impedance increases.

This tweeter is pretty tough, the pair I had many years ago held up to much abuse with a 1st order crossover around 3khz, if I remember correctly.

That particular tweeter has had a good reputation for years, but it's been made by several different Chinese manufacturers. There has, more than occasionally, been QC problems with it. I'm not saying don't use this tweeter, but you shouldn't assume it's as good as it has been in the past.

 

[Swerd]

There also may be problems with the Tang Band W5-2143 5" mid range driver.

First, Tang Band does make some good drivers, but it can be hard to know by their published frequency and impedance curves. Let's be polite and say that Tang Band is known to be optimistic. To know how this driver performs, you must measure it yourself. The same goes for the other two drivers you've selected, even though Parts Express generally is more realistic about their drivers. The final reason why you should measure this driver is that Tang Band does not supply data, such as the data files that Parts Express, and other manufacturers supply.

Below are Tang Band's curves for the W5-2143. I have a hard time believing any 5" driver can perform so smoothly out to 20 kHz (red trace).

In the impedance vs. frequency curve (blue trace), notice those two blips at about 1 and 3 kHz. Irregularities in impedance curves, such as those two, often (not always) indicate unwanted resonances. Those frequencies are in the range you intend to use. I don't know if you'll hear them or not, but this is another reason to measure it's performance yourself. I did look in the frequency response curve at 1 and 3 kHz, and saw little to correspond to those impedance blips. But I've already warned about trusting Tang Band's published frequency response curves.

If you plan to use this driver with a 1st order crossover at 3200 Hz, you must consider the rising impedance out to two octave higher, up to 12,800 Hz. As you can see, this driver's impedance rises to well above 8Ω impedance. How does that affect your selection of crossover components?

While we're looking at these curves, note that Tang Band only shows a single trace for frequency response. I have to assume it was measured on-axis, but Tang Band doesn't say. I would like to know how the frequency response drops as the measuring microphone is moved to 30° and 45° off-axis. Most manufacturers do show this, but not Tang Band. How does this driver behave off-axis at 3200 Hz or higher? Will it beam? That will have a large negative impact on a smooth crossover to the tweeter, because a 1⅛" dome tweeter will have a much wider dispersion at 3200 Hz than any 5" mid-range driver will. The discrepancy between the two will be noticeable. It has been described as having a collapsed hole in the lower treble.

 

[Swerd]

To sum up my two long posts:

• Measure the impedance and frequency response curves of your drivers. Or, download those data files from Parts Express.
• Avoid using those online calculators. Instead, use a computer program to design the crossover. Their advantage is quite big. They can simulate a predicted frequency response curve that allows you to see the effect of changing crossover component values, and especially crossover designs.

TLS Guy does use one of those computer-aided crossover design programs. Importantly, he actually knows how to use such a program, and he has kindly offered you his help. Even if you spent the money on software like this, as well as the other necessary gear, it would still take you some time before you got any good at using it.

I see numerous good reasons to avoid using 1st order crossovers. Personally, I'd suggest using a Linkwitz-Riley 4th order crossover. It allows you to consider a driver's performance ±1 octave instead of 2.

Remember what TLS Guy said, you have to consider the speaker's performance including both the natural roll-off of the drivers combined with the electrical roll-off generated by the crossover filters. It is easily possible to achieve acoustically measured LR 4th order roll-offs without using crossovers that look like electronic 4th order filters. With computer aided crossover design software you can see that simulated on your screen, without having to build anything.

And, I'd look into other mid-range drivers.

 

[Verdinut]

That large 6 mH inductor coil, you mentioned is meant for the woofer low-pass filter, right? Because it has a lot of wire, the DC resistance is about 1.5Ω. If you selected a 6 mH coil because you assumed a constant impedance of 8Ω, it won’t work as you plan because the woofer’s impedance increases.

The problem here is not so much because the impedance would increase, but because the DC resistance of the inductor is close to 20% of the woofer's impedance. For good results, the DC resistance of a series coil should never exceed 5% of the driver's nominal impedance. Any excess of resistance in series with a woofer decreases the driving amp damping factor which results in a reduction of the driver's transient response.

 

[TLS Guy]

So you are saying that because of the rising impedance the relationship with the inductor changes as frequency rises, resulting in not achieving the attenuation that was expected? In this case, there wouldn't be enough attenuation of the woofer to mitigate the large peak in response starting at 1500hz? If you raise the crossover frequency then would this not just exacerbate the problem? By power response you mean differences in off axis response, lobing? How would you go about suppressing breakup modes, with a notch filter?

I don't want to be told what to do, I want to understand the principles of what is going on so I can analyze it myself and make my own conclusions and decisions based on my needs/desires.

This is all part of the art of crossover design. Practically all woofers behave like the one you selected, so this is close to a universal problem and a reason why first order crossovers seldom work. I doubt I will have to design a specific notch filter.

I have been preoccupied today with an unexpected problem. I will get started on the problem tomorrow, and post a complete pdf here for you as an attachment.

I'm actually quite optimistic that we can come up with a good cost effective design here. 400 Hz will be a really good crossover point. For one thing 400 Hz is the power divide for most music sources. So you have to devote as much attention to the power band response above and below 400 Hz. Even experienced designers often overlook that point. Inadequate power band in the 400 Hz to 3.5 KHz range, is an all too frequent problem.

 

[lovinthehd]

FWIW you need to delve into the subject more than expect some minimal info posted to yield meaningful results.

 

[TLS Guy]

There was absolutely nothing educational in the others' posts. There is a very definite trend of this kind of behavior on forums of all kinds, it's like being in the comment section on youtube. Anyway, thank you for your mostly constructive response.

If you look at the amplitude graphs the Dayton 15 doesn't really start to peak til 2.5 octaves over the 220 crossover point. The Tang Band has a 3db peak around 4k and 5db peak between 8 and 10k and starts peaking again after 12k. Interestingly, the Dayton tweeter has approximately a 4db dip between 8 and 10k. May encounter slight peaks at 2 and 4k. Of all the drivers I looked at in my price range these seem to mesh much better, and be much tamer than others. Not to mention, I've owned some version of all these and was very pleased with them. Here are the links showing the specs and graphs for the drivers in question:

https://www.parts-express.com/pedocs/specs/295-325-dayton-audio-dc380-8-specifications-46152.pdf

https://www.parts-express.com/pedocs/specs/264-958--tang-band-w5-2143-spec-sheet.pdf

https://www.parts-express.com/pedocs/specs/275-070-dayton-audio-dc28f-8-silk-dome-tweeter-specifications.pdf

As far as power handling, these 5" mids have more power handling(and lower fs) than the dual 3" tang bands I currently have crossed over at 200hz, 1st order, and I have cranked these many times and had no problems, and surprisingly, not much distortion. Is there some other reason that crossing over low passively can have deleterious effects?

The woofers will be in separate cabinets, the mid and tweeter in their own small cabs, flush mounted.

I am not after perfection, just good, and I don't have a particularly refined ear. After building quite a few speaker systems, most of the early ones with prefabbed 12db crossovers, and some with custom 12db crossovers, built to recommendation, I have had a number of disappointments. The system I have now with dual 3" TB bamboo drivers and dayton sub crossed over at 200hz is the most pleasing yet, although not good off axis and lacking great high highs.

I'm sorry to tell you, but there is an insurmountable problem at the first post. That bass driver does not model well in ported or sealed configuration. It is a classic car driver by design and NOT suitable for home audio. It has the classic peaked response of car driver.

So here are two models of your bass driver overlaid.

The top line with an F3 of 35 Hz, is the ported model. However this is not a good ported driver, as it requires far too large a box to justify that F3.

The other line, is the closed box model this driver is designed for. The F3 is 56.2 Hz. The driver has not xmax reserve to allow for equalization.

So you need to pick another woofer.

However a far better approach is to embrace a more modern approach. We can get a much better bass response and power response out of smaller drivers these days.

If budget is a concern and I sense it is, then a cost effective two way is the answer. You seem to have a desire for first order crossovers. I do have a nice transmission line design on file that has first order crossover and very few components.

So I'm sorry to have to tell you that the concept you presented for review in in fact a non starter. Don't waste your time on it.

 

[KNOTSCOTT]

I'd look to upgrade at least the tweeter, and maybe change the woofer to something with a smaller diameter and longer throw. If you do, you'll likely need to recalculate crossovers. Parts-Express and most driver suppliers can offer technical suggestions for crossover points and types for each driver they sell.