SEAS ER18RNX / 27TBFCG MT 2-way: Listening impressions

[Jay_WJ]

If anyone's interested in this driver combination, here's information from a person who built these speakers using my crossover design.

-jAy

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Hi Jay,

I`ve just finished your Seas ER18RNX TM design with 27TBFC/G tweeter option. I`ve used my own sandwich (MDF + plywood) enclosure design with front mounted Precisoion Port and Sonic Barrier dampening. Crossover and driver spacing is exactly the same as on your drawings and I have to admit that I`m impressed with sound quality of this speakers. Thank you for creating and posting this great design on your website.

At the moment I`m testing these speakers and I use Plilips DVD as a source cause I`m waitng for a new DAC. Anyway I can write some first impressions.

I`m using a 16,5 litres enclosure with bass reflex tuned at 35 Hz. In my small listening room (15 m2) bass response is very smooth with very nice low end extension. Low tuning provieds a bit lean bass with soft roll off which combined with room gain allows even 30-35 Hz tones to be well defined.

Tonal balance is very even, in my opinion full BSC is an exellent choice for those speakers. Overall response is very smooth and sound stage is huge in every dimension. Speakers just "disappear" in my listening room and completely fill it with sound. 27TBFC/G is really a great tweeter and I didn`t noticed any kind of stress from it crossed over at 1550 Hz, even at very high SPL.

For now I just can`t write any negatives. For a 2 way monitor with single 18 cm woofer they are just amaizing in every aspect. I belive that such great results are achived through well designed crossover combined with good drivers and extreamly rigid sandwich enclosure with additional wood bracing and two separated chambers for tweeter/crossover network.

Most factory speakers sound thin and boomy compared to them because of manufacturer's limitations. They can`t cross too low cause they are afraid of tweeters being overloaded, they use thin and simple enclosures cause they are much cheaper, they use only few db BSC cause speakers must sound lound in shop and have high "on paper" sensitivity. All those limitations provides poor performance when compared to well designed DIY
speakers and it`s very easy to hear the difference. At the moment they are absolutely the best monitors I`ve ever heard.

I`m using them with an old Sony TAF670ES solid state amp (90/140W) and low sensitivity is not a problem for me. Anyway even though those speakers have around 83 db sensitivity I find them at least as sensitive as some speakers I had with 87-88 db sensitivity claimed by their manufacturer.

Btw, there is still some work to be done to make those speakers look really good, but meantime feel free to use those fotos.

- Chris

[Jay_WJ]

Here are some more photos showing crossover and cabinet building. Impeccable work all around. I'm very impressed.

-jAy

[Dave Bullet]

Congrats Jay. It must be satisfying when someone else gets joy from a design you've produced.

David.

[DavidLR]

Jay & Chris-

Very nice, both of you. Jay, I have browsed your speaker building website, am interested in your designs because you are a classical music afficianado, as am I. I think it's more difficult to find speakers that do well with classical, particularly the violin. Most speakers do OK at lower volumes but, get an orchestra going full tilt & violins harden up & get harsh pretty quick !

Also, Jay/Chris, most bass reflex speakers have the port in back, yours are in front. What are the pros & cons of each ?? Is it only cosmetic or are their acoustical reasons as well. Seems to me , with the port in front, the speaker wouldn't need to be as far out from the wall to avoid muddying the midrange.

The enclosures look larger than the ones Krutke (SR71) uses for the same drivers. If so, is this part of the deeper but leaner bass ?? The dowels , I assume, is to align the box pieces during assembly ? Good idea !

Like many people on this forum, a relative newbie here, just trying to get informed & educated. Thanks.

Dave

[Jay_WJ]

Originally posted by DavidLR
[B]Jay & Chris-

Very nice, both of you. Jay, I have browsed your speaker building website, am interested in your designs because you are a classical music afficianado, as am I. I think it's more difficult to find speakers that do well with classical, particularly the violin. Most speakers do OK at lower volumes but, get an orchestra going full tilt & violins harden up & get harsh pretty quick !

I find that one of the reasons why music doesn't sound right is recording quality. In theory, Redbook CD should be nearly "lossless" when recorded properly. But in many cases, music's mastered poorly on CDs. Have you tried SACD and DVD-A? Most of them are much better than CD.

Also, Jay/Chris, most bass reflex speakers have the port in back, yours are in front. What are the pros & cons of each ?? Is it only cosmetic or are their acoustical reasons as well. Seems to me , with the port in front, the speaker wouldn't need to be as far out from the wall to avoid muddying the midrange.

In fact, front-porting is not what makes the speakers usable close to walls. A major factor in close placement to walls is baffle step loss / boundary reinforcement issue, not the port location. In theory, only a few inch clearance between the port opening and the wall is enough for the proper functioning of the port. BTW, here's a good experiment about the effect of port location in BR system:

http://www.zaphaudio.com/tidbits/

Find "Front port mounting" in the middle of the page.

The enclosures look larger than the ones Krutke (SR71) uses for the same drivers. If so, is this part of the deeper but leaner bass ??

A little taller baffle can change the midrange tonal balance a bit, but it won't do so dramatically. A major difference between Zaph's design and mine is more in a little different baffle step compensation and crossover point as I pointed out in my web page.

[peter_m]

Jay, on your site you show your phase tracking between the tweeter and woofer:



Do you have such a graph for Zaph's design?

[peter_m]

Originally posted by DavidLR
The enclosures look larger than the ones Krutke (SR71) uses for the same drivers. If so, is this part of the deeper but leaner bass ??

I noticed he used a sealed compartment for the x-over which sacrifices some of the volume. By how much larger is it larger?Who knows. But Zaph did hint in another forum that if he was building the enclosures from scratch he would have gone to 16L instead of the Madisound's 14L.

Peter

[Jay_WJ]

Originally posted by peter_m
Jay, on your site you show your phase tracking between the tweeter and woofer:

Do you have such a graph for Zaph's design?

Yes, I have it in my SW file. But don't bother. It's only approximation given by simulation. Yes, I know it's reasonably accurate. But that's it. Phase tracking of Zaph's design also turns out to be excellent in my simulation.

[Jay_WJ]

Originally posted by peter_m


I noticed he used a sealed compartment for the x-over which sacrifices some of the volume. By how much larger is it larger?Who knows. But Zaph did hint in another forum that if he was building the enclosures from scratch he would have gone to 16L instead of the Madisound's 14L.

Peter

Oh, I only considered the baffle size, not the cab volume, when I replied to Dave. Notice that he also used a separate sealed chamber for the tweeter, too. He must be perfectionistic. So he used 16.5 liter net volume for BR tuning and tuned the port to 35 Hz, which I think will work a bit more optimally than the SR71 kit's volume and tuning.

[DavidLR]

Yes- cab volume is what I was referring to. I had a chance to audition the SR71's & was pleased by both the sound & small size of the box. The picture of Chris' box appeared to be larger but perhaps it wasn't. Hard to tell sometimes from pics.

Re the port, I understand some of what you say. I"ll take your educated word for it. I've always understood that a speaker close to the wall usually reinforces the bass at the expense of clarity, unless the speaker was specifically designed to take that into account.