Seriatim from InDIYana and MWAF

[HiHoSilverado]

So, I have been listening to my Seriatims for about a year and have honestly not been very satisfied with the sound. Compared to my Zaph SR71s, they sound muffled and flat, almost like they are playing behind a heavy blanket. If I crank up the volume and sit directly in the sweet spot, the tweeter seems to come out more, but the high end is just not what I expect from a design of this cost. I took the stuffing directly behind the woofer out of the cabinet, which helped open up the lower midrange response a lot, but at the cost of some increased boominess. This is great for electronic music and rap, but not so much for jazz. That said, some of my favorite vocal recordings really shine on these. I have checked over the crossover to confirm that I followed the design correctly, so I am thinking the next step is to start tweaking parts. I plan to start by swapping out the 8ohm resistor on the tweeter circuit to a lower value to increase sparkle. Any other ideas would be appreciated.

[howard]

I have read that on some of the ribbons that HIvi has reversed the +/- signs. Maybe pull the tweeter and try reversing the leads to it?

[jhollander]

My voicing would not be considered muffled or laid back. With that baffle new measurements and a simple x-o would be a good start.

[HiHoSilverado]

Thanks, I was thinking the tweeter leads could be reversed, so I will start there. I will post updates as I begin testing. Sent from my iPhone using Tapatalk

[danmarx]

I recently built a similar 2-way using the same drivers though I didn't do the series crossover, I did a traditional parallel 4th order, but I originally shot for 6 dB of BSC and felt it sounded too muffled also, so I backed off the BSC by about 3 dB and have been much happier. I'm not sure what the original designer's crossover does as far as BSC, but toning it down from a full baffle-step circuit can really brighten up the sound, especially if the speakers are placed close to wall. Have you measured the speakers? A quick FR sweep can tell a lot if you've got the gear to do so. Tweaking crossovers by ear can be tricky business unless you already have a baseline measurement and know that everything "looks good" and are just making small adjustments to taste. I can vouch for this driver combo though, the RT1.3 with the RS180 can sound absolutely fantastic together.

[HiHoSilverado]

Thanks, Danmarx. I have been experimenting with resistors in the tweeter circuit and have found that reducing the tweeter padding resistor to 6.5 or 7ohm brings the high end where I want it. I have also tried reducing the BSC, but found that it increased the honk of the upper midrange, which I would prefer to reduce to get a dryer sound. I am new to crossover tweaking and unfortunately do not have a testing set up yet, so I am doing this by ear. That said, I am a trained musician and have built other high quality speakers, so I have a good idea for what I am looking for. I think the next step is probably to buy a few caps and coils and experimenting to see if I can get the woofer response to where I want it.

I hear the promise in the combo, which is why I built this design and on certain songs they sound incredible. They just need a little work to get them where I want them, which is a big part of what this hobby is all about.

[jhollander]

I can work on a new x-o if need but the quick tweak would be to remove the 3.5 ohm resistor and jumper across the 8.0 ohm resistor

[HiHoSilverado]

Thanks, I tried jumping the 8ohm tweeter padding resistor and it was way too bright. Swapping to a 7ohm seems like the sweet spot for me right now, where the tweeter is crisp but not standing out. This seemingly minor tweak has made a significant improvement in overall presentation. I can hear a definite volume difference between .5ohm resistor values, so I think anyone building these would be wise to buy resistor pairs from 6.5-8ohm values and trying different levels out before finalizing the crossover. I am also hearing a peak in the upper midrange, do you have a suggestion for a component to adjust if I want to slightly steepen the woofer crossover slope? I also need to play around with stuffing again now that I have the crossovers out of the box and a bare box floor. Thanks everyone for chiming in! I realize that I am flying blind without measurements. Sent from my iPhone using Tapatalk

[jhollander]

This was the intent of the design, 8th order 48 dB per octave

[dynamo]

I am doing a build right now with the HiVi Rt1.3 and the polarity was backwards.

[HiHoSilverado]

Checking back in with this build. After a lot of frustration not getting a sound I liked out of the crossover as designed (probably either a build error or noncompatability with the replacement tweeter) I changed gears entirely and switched to an active setup that I tweaked to get the best possible sound to my ears. This resulted in a -18db (3rd order) slope high pass for the tweeter at 3.15khz and a -12db (2nd order) slope low pass for the woofer at 1.2khz for a crossover point at about 1.6khz. I used VituixCAD to back into a crossover design that mimicked my active setup and came up with the design below. Parts cost about $80 for the new boards, but, holy smokes do they sound great!

With the new crossovers the sound is highly detailed and transparent. The Dayton woofers go surprisingly low (which is not new), but the integration with the tweeter is now excellent and these have become my favorite speakers. They get loud effortlessly and while their midrange and mid-high reproduction is not as "dry" sounding as my SR71s, they absolutely smoke them in bass response and overall liveliness of the presentation. This driver combo is fantastic for the price point, the big tradeoff being a narrow sweet spot, which I believe comes with the territory for this type of tweeter.

As for tweeter polarity, there was a significant difference in sound when I switched polarity back and forth. The schematic below assumes the tweeter lead marked red is the positive lead, but VituixCAD suggests this design will result in a significant SPL dip at the crossover point. So, either HiVi marked the negative lead red, or mismarked the positive lead. Either way, the builder will hear distinct compression in the upper midrange when the tweeter is incorrectly wired.

This project has been a big lesson in crossover design for me and has yielded fantastic sounding speakers. If at first you don't succeed, try, try again!

[HiHoSilverado]

Crossover pics, note that the tweeter lead designations are reversed from the design because of the tweeter polarity indication confusion. Sent from my iPhone using Tapatalk

[bungelow_ed]

Crossover pics, note that the tweeter lead designations are reversed from the design because of the tweeter polarity indication confusion. Sent from my iPhone using Tapatalk

Very much like your build, including the repurposed desk legs. Quick question, where did you get the buss connectors? Used to be able to get them everywhere. Last time I looked for them they seemed to have disappeared.

[HiHoSilverado]

I got the bus connectors on Amazon. Sent from my iPhone using Tapatalk

[Dukk]

^ I just picked up Qty.10 12-position strips on Amazon as well. $15 in Canada with Prime free shipping. I have no idea where I would even go to find these in a brick and mortar store these days...