No pics at the moment, I just took the drivers out of the box. So far I'm really impressed with how well behaved they are. My references using the Scanspeak Discovery 15cm woofer and 9130 tweeter are just hopelessly outmatched for clean output. They also project a very large, and more holographic soundstage.
Good!!
According to Erin (from EAC) the woofer is very good distortion wise above 100hz... ideal to high pass it to a couple of SW.
I will keep posted.
Hi,
Why ? A driver can be too big when comming in its beaming area. But if you cross-over lower what could be the problem ? It is flat enough on axis and off axis for a text book crossover, no ?
A 5" waveguide has lost directivity by 1.3khz. Which also means no gain on-axis, so the tweeter is being pushed pretty hard, as hard as a tweeter without a waveguide. If you have a waveguide, you have the directivity to match the woofer at higher frequency anyway, so why push so low?
Makes sense. I missunderstood believing he was talking of a too low cut-off for the 5" woofer and not the WG... my bad !
Should the driver below the WG always on the same size ? What is the lowest frequency you would crossover a horned 3/4" tweeter, please ?
Should the driver below the WG always on the same size ? What is the lowest frequency you would crossover a horned 3/4" tweeter, please ?
Is the (lowermost) frequency down to which a waveguide adds on-axis gain dictated by the diameter of the waveguide, or its depth, or its flare angles, or something else?
Are there equations that describe the general relationships?
Are there equations that describe the general relationships?
Hi Brandon!
I hope you´re fine. I wondered if you eventually measured the 4,5" waveguide for the T25B-6. I am very intrigued to know your results.
Meanwhile I keep working in progress with the cabinet:
Attachments
And a fair reason. I should have mentioned that the 1,3kHz both was too low for the 5" WG and that it was unnecessarily low for the 5" Textreme, since the little SB woofer has a very nice and even response up to around 2-2,2kHz - also the reason why I chose it. Other small woofers do not play as smooth when they start having the narrowing of the dispersion.
My take on the matching between woofers and tweeters - is by looking at where the woofer starts to beam - around the area where the off-axis is max 2-3dB lower than the on-axis. Then I mate it with a waveguide that start to do the same - at around the same frequency. Because then my experience is, that it is much easier to make them coop, so that the tweeter take over smoothly from the woofer.
Further - the woofer should preferably be smooth on all axis'. And that again require the woofer to be extended enough for the filter to work and create the proper acoustical slope. So if a woofer drops off very quickly off-axis. You then have to cross even lower, which again require a bigger WG, or use a steeper filter - whitch again can lead to trouble.
Try to think of it like a teamwork of compromises. All we like in any speaker design, is nothing that is too abrupt. We like smooth... because then we can't hear all the little compromises 😊
I agree that the response of the 5" Textreme is very good.
My idea about crossing at 1,3kHz was/is that there is a better match with the center-to-center distance of the woofer and tweeter. Crossing higher, where wavelength is shorter, might be detrimental on that aspect. And at 1,3kHz the directivities already match perfectly (as they indeed still do at 2,2kHz).
Manufacturer Bliesma lists in their documentation that the T34A can be crossed over at 1,3kHz.
My cabinets are ready now. I will try out both the 1,3kHz and 2,0kHz crossover points. Very curious about the difference in sound!
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Oh yes.... please try it out. My words are not law, and learning what you personally like, is best discovered by trying it out yourself 👍
Your WG is also way smaller than the 5" I use. Which might result in your cabinet/baffle having way more influence on the final acoustical result. Therefore, my approach might not help with your design. But again.... I will happily look forward to your measurements 🤓
This morning I have tried out different crossover frequencies.
2kHz sounds quite awful. Probably because of cancelations and phase issues. I didn't try crossover types other than 24db however.
2,2kHz sounds a lot better. No cancelations at my listening distance of ~4 meters.
1,3kHz sounds even better. Highs are more detailed and sparkling. I like it a lot with classical and chamber music.
Comparing 1,3kHz and 2,2kHz, I think I mainly hear the differences in character between the drivers. The M13TX is detailed but slightly mellow. The T34A is extremely detailed and sparkling.
The finished cabinet, on wheels for now 🙂:
This makes more sense, I would be very surprised if there was a big subjective difference between 2.2 and 2.0 k...
This is such a nice project, it is unfortunate that it is burried in the middle of this long waveguide thread. You should start a new thread and tell us about your new speaker. I would be very interested in construction photos, measurement results, simulation results, etc...
@fluid - nice job on the waveguide. It seems to be perfect for this tweeter in this application.
J.
Nice looking speakers 👍 But the shallow WG surely makes everything a different beast, than Augerpro's options. Maybe the wider dispersion is just what you like - and that is totally fair 😊
I'm still wondering a bit why the TX sounds "mellow" and that crossing at 2kHz makes everything so bad 🤔 Except that the WG is so shallow that it still "sparkles" - which I find to be a less charming feature. I heard the T34B without WG... and that was a "mess" for my ears. All over the place and no stereo "focus".
Crossing at 2kHz and 2.2kHz sound similar (I initially made a mistake with the 2kHz test).
Maybe sparkle is not the right word. But there is certainly quite a difference in detail and transparency if the T34A does the 1.3kHz to 2kHz range vs the M13TX. If it is caused by the characteristics of the driver, or maybe (also) by phase issues because c-to-c is about 0.75x the crossover wavelength, I don't know.
With a previous 2-way I made with the T34A without waveguide, I had a bit of a similar "mess" experience with the T34A. @fluid 's waveguide really improves the imaging and stereo focus. No mess anymore 🙂 . It still has a wide dispersion, which I like. But the speakers are much better for serious listening with this waveguide.
I found something similar in my system. I have a MW16TX-4 and a TW29TXN-B. I have experimented with 3rd and 4th order crossovers, from 1.6k to 2.2k. There is a small improvement in transparency when the tweeter handles 1.6k to 2k, versus the case where the mid driver handles that range.
j.
Interesting - there are a few things happening which could contribute to that effect.
The tweeter has broader radiation at that frequency range - more energy in the room when the speaker is linear on axis. 1,5-2kHz is a sensitive area.
The membrane of a tweeter is perfectly stiff at these frequencies.
THD of the tweeter COULD be higher at these frequencies and could produce overtones which fall in the area of 3-6kHz which adds "freshness" but should switch into "harshness" at higher levels.
The tweeter has broader radiation at that frequency range - more energy in the room when the speaker is linear on axis. 1,5-2kHz is a sensitive area.
The membrane of a tweeter is perfectly stiff at these frequencies.
THD of the tweeter COULD be higher at these frequencies and could produce overtones which fall in the area of 3-6kHz which adds "freshness" but should switch into "harshness" at higher levels.
Really wondered about this - like where should the extra quality come from?.
The MW13TX and the new Purifi Midrange - within 400 to around 2500Hz, where normal midranges normally work best.... they are actually very alike when it comes to distortion.... or am I missing something?
https://hificompass.com/en/speakers/measurements/purifi/purifi-ptt65m08-nfa-01a
https://hificompass.com/en/speakers/measurements/satori/satori-mw13tx-8
The MW13TX and the new Purifi Midrange - within 400 to around 2500Hz, where normal midranges normally work best.... they are actually very alike when it comes to distortion.... or am I missing something?
https://hificompass.com/en/speakers/measurements/purifi/purifi-ptt65m08-nfa-01a
https://hificompass.com/en/speakers/measurements/satori/satori-mw13tx-8