Simple test of Dayton Audio MK442T 4" 2-Way Transmission Line Tower Speaker Pair

[nurmdog]

Now that I have basics down and REW working I did a quick comparison of my current project, a pair of Dayton Audio MK442T 4" 2-Way Transmission Line Tower Speakers. I purchased these on sale and got a coupon, of course. I typically use a pair of KEF R3 speakers in mahogany that I absolutely love, but I also love tinkering. My 4 year old hit one of my KEFs in the woofer and added a small dimple.... I love her. I am considering using cheaper speakers for a few more years until my 2 and 4 year old get older and there is less chance they will destroy my beautiful expensive KEFs.

I have been making some speakers on my own for years now and I have also purchased and sold probably 10 pairs of cheap speakers. I am fascinated with the idea of a set of $100 - $200 speakers that sound good enough, or even better than good.

I built myself 3 different pairs of speakers using a transmission line. I have loved the idea of a transmission line, and the sound, since I heard some Focal Daline 3.1's back in 1997 and wanted to buy them. My fist pair had Seas 6.5" metal woofers with Focal inverted metal dome tweeters. These were my attempt back in the 90s to make a better home made version of the Focal Daline 3.1 speakers. I'd say they were similar in sound and quality, I was happy with them. Those were stolen shortly after. My 2nd pair was using 5.25" Tang Band full range Bamboo drivers, those sounded pretty darn good for a single driver. I took them apart to save space, still have the drivers. My 3rd pair of T-lines was 8" full range Tang Band Bamboo drivers, still have those sitting in the garage annoying my wife. They sound pretty darn good as well for a single full range. I have toyed with adding a full range or tweeter to those using 1st order crossovers. I came up with some decent results (as far as sound) but never measured it.

The concern I had with the Dayton Audio MK442T speakers started before I bought them. I don't like small tweeters. It's a whole discussion and thing with me, size matters. Maybe it's just me but I have a strong opinion on tweeters, I generally dislike 1" and I don't want anything smaller than 1". The Dayton has 3/4"dome tweeters.

I separately purchased two cheap tweeters (really 4) from Parts Express along with the speakers and the measurement mic. I made measurements of the stock speaker and then two other measurements with the 2 different tweeters balanced on top but facing the mic. I did this because none of them are an exact fit and I don't want to cut up the speaker until I have made a decision.

Test setup
So this might be weird...
MAC Mini is sending audio over Airplay to my listening stereo. Old Apple TV to the Schiit Audio Modi Multibit DAC using TOS Link, Marantz AV7701 preamp, Emotiva XPA GEN3 2 channel amp, and a Pioneer Elite SW-E10 subwoofer.

Using REW and the newly purchased and setup Dayton Audio Umm-6 Mic on the MAC mini. Measurements are about 6ft (I was within a few inches each time).


So why did I go with these tweeters? Because they are 4 ohm, relatively close to the physical size of the original tweeters, their SPL is similar to the speaker, and they are not expensive.


Stock speakers with the 3/4" dome tweeter.

Speakers using Peerless XT25SC90-04 1" Dual Ring Radiator Tweeter.

3rd, Dayton Audio Dayton Audio ND25FA-4 1" Soft Dome Neodymium Tweeter

These may not be the best pics or graphs, sorry. What I see, and hear, is that both of the 1" tweeters are a better match than the original 3/4". The stock tweeter is actually quieter than the woofers, you can see it slightly tail off.

Quick note. In general my ear likes the sound of the Peerless best, but the 1" Dayton is close. It's hard to describe the difference when listening to music, but there is some difference.

So I am looking for anyones thoughts on this. Suggestions for other tests to try? Thoughts about the results or test methods? Anything I should consider improving? I am happy to test again and post other results if anyone is interested.

Thanks!

 

[nurmdog]

All 3 in a graph

I should point out Dayton went with a non traditional crossover, here is their description. Being that the tweeter is mostly from 3k up that is the part that should change the most, I would think. EDIT: also important, the left speaker was used for stock. The right was used for the other 2 tests, so room position is slightly different for the stock one.


The crossover featured in the MK442T utilizes a 3 kHz, 2nd order low pass and a 3rd order high pass section. The board is then affixed to the rear of the recessed terminal cup which features a pair of 5-way gold-plated binding posts. The crossover was designed and optimized to deliver the smoothest, flattest frequency response possible.

 

[Darryl]

I would interested to see your justification for heading down the transmission line route when a good ported or passive radiator system will out perform it in every aspect.

 

[fpitas]

Adjusting the tweeter level is generally not tough: one resistor. That's really a listener preference, anyways. But maybe you prefer the smaller dispersion of larger tweeters. If that's the case, you might like the Dayton 1-1/8" dome tweeters.

 

[mhardy6647]

Adjusting the tweeter level is generally not tough: one resistor. That's really a listener preference, anyways. But maybe you prefer the smaller dispersion of larger tweeters. If that's the case, you might like the Dayton 1-1/8" dome tweeters.

Using one resistor would also change the crossover point, wouldn't it?
Seems to me one would need two resistors (i.e., an L-pad) to adjust the level (downwards).

 

[fpitas]

Using one resistor would also change the crossover point, wouldn't it?
Seems to me one would need two resistors (i.e., an L-pad) to adjust the level (downwards).

A little. But lots of simple designs use a single resistor change for tweeter level. Of course, in this case I have no idea what the circuit looks like...

 

[sarumbear]

A little. But lots of simple designs use a single resistor change for tweeter level. Of course, in this case I have no idea what the circuit looks like...

Lots of designs are wrong. @mhardy6647 is giving good advice.

 

[sarumbear]

Adjusting the tweeter level is generally not tough: one resistor.

Not me. I don't own or make anything of the sort. Talk to the designers.

I was commenting to your above quote where you opinionated on design.

 

[nurmdog]

I would interested to see your justification for heading down the transmission line route when a good ported or passive radiator system will out perform it in every aspect.

I don’t agree with that entirely. The transmission line has a larger and longer port than a ported speaker. The waves travel longer and have less back pressure.

Transmission line, ported, and sealed all sound different and “best” is a matter of opinion.

For subs I like sealed best, for speakers transmission lines. Just my opinion based on how they sound to my ears.

 

[Darryl]

I don’t agree with that entirely. The transmission line has a larger and longer port than a ported speaker. The waves travel longer and have less back pressure.

Transmission line, ported, and sealed all sound different and “best” is a matter of opinion.

For subs I like sealed best, for speakers transmission lines. Just my opinion based on how they sound to my ears.

Hmmm, the output of any port is completely under control of the driver.
Your theory that there is less backpressure would mean that the driver has less control of port output and that is not a good thing.
In a ported enclosure at the box frequency the driver has maximum back pressure, as you want to call it, but port has maximum output, the driver almost stands still and the port does all the work. This is an indication of efficiency of energy transfer of the driver to air movement and this is always a good thing.
A transmission line is merely a subset of ported enclosures as a whole and one that has in general less output, less control of the port and far more port resonances to deal with.
It does appear from your graphs that you enjoy an out of control bass output at 60hz with heaps of ringing.
I think you are blinded by your belief system.

 

[nurmdog]

i see your point but I’m no convinced. My liking a transmission line is based on my ears , not a belief that the technology is better. I’ve made 3 transmission line speakers , purchased one, and extensively listened to others in a store. It isn’t perfect, no speakers are, I just think the bass sounds better and more linear.
As for the bass spikes in my charts above, I think most of that is the physical characteristics of my room. Some can be the transmission line for sure.

Here is what wiki says

Transmission line loudspeaker - Wikipedia

en.m.wikipedia.org

 

[nurmdog]

So let me get back to the spikes, it was a problem. I just recalled that those first graphs were with my first microphone. I made an RMA and it took MONTHS to get a new microphone. With the new mic I made new measurements and they looked better. The next step was I allowed Audessy to run on my Marnatz and let it do it's EQ thing. I adjusted the subwoofer as well to try and balance it all out.

The outcome was this graph below, it's not perfect but it's pretty good. It sounds good to me as well. The one thing I noticed right away is that Audessy adjusted the output so that it is quieter, I am estimating it moved the output down 1.5-2 db. I say this because I was consistently testing with the same mic in the same position, in the same room, and with the same output volume. The only thing that changed was the EQ settings on the Marantz and adding/removing the sub.

What is the spike around 250hz? I don't know and it's slightly annoying, it's about 6db above my 88db centerline. There is also a drop at about 90hz of 5db, my sub should be great at that frequency so I don't know what that is either. All other parts of the spectrum that I can hear sound great. Thanks for the interest everyone.

so